996 C4S ?Rebuilt Engine from JR Failed Again After 40,000 km? Looking for Advice

Hi everyone, I’ve been the owner of a 2003 Porsche 911 996 C4S Cabrio since 2008. Back in 2009, the original engine failed due to the typical issues — IMS bearing failure and scored cylinders. I wasn’t able to find a trusted local mechanic, so after doing a lot of research, I reached out to Jake Raby. The engine was rebuilt by his team and sent back to me in 2010. The total cost — including parts, labor, and shipping — was around $30,000. From 2010 to spring 2025, the car was driven about 40,000 km (~25,000 miles). Oil consumption was very low — basically negligible between changes every 3,000–5,000 km. 2010 And now, the engine has failed again. This happened on the first drive of the season (the car is stored during winter). There was a faint ticking noise during acceleration, which sounded like a noisy lifter. After about 15 km of driving — a loud bang, sudden loss of power, and what clearly sounded like pistons hitting valves. I stopped immediately. Here's what we found with my mechanic: Piston in cylinder #1 was loose Timing chain on the right bank had jumped Piston marks on the right-hand side Piston debris in the crankcase One chunk of piston ended up under the timing chain sprocket — likely the cause of the chain jump After full teardown, things looked even worse: All JE 96MC4 pistons (installed in the rebuild) have cracks on the skirts. My mechanic says he’s never seen that kind of damage on JE pistons before. Oddly enough, the liners still have visible crosshatching and no scoring. We reached out to Jake Raby again asking for guidance on piston selection and next steps. Shipping the engine back to the U.S. is no longer feasible for us. He replied and said: "Stephen from LN Engineering is now assigned to this ticket and he can assist you." Unfortunately, we haven’t heard anything back — even after several follow-up messages. So I’m turning to the community here for advice. I have a few questions for anyone with experience in this area: What material were the liners supplied by LN Engineering back in 2010? Were they always aluminum, or could they have been iron? What piston-to-wall clearance is recommended for these liners? My mechanic believes an excessive clearance can cause piston slap at TDC and possibly lead to skirt cracking. Has anyone else seen similar failures on JE pistons (particularly the 96MC4 model)? Any input, especially from those with engine building experience or who've dealt with similar issues, would be greatly appreciated. Thanks in advance!

I seriously doubt they are not returning your messages if you are legitimate. Quite frankly, it sounds like you need a mechanic that knows something about the M96.

Sir, When logging into the FSI ticketing system I see a message from you 5 days ago, followed up with the message that you quoted from Mr. Raby as a follow up the same day. I then see the assignment of this ticket to Stephen, as Mr. Raby had directed which occurred at 8:30 on June 20. Stephen then replied to the assignment at 4:56 the same afternoon. This is the last ticket response in this thread. You can see this here in the screen capture, noting it is the final reply to the thread, which is still open for customer reply. I am unaware of any other messages that you made mention of, and based on what I have to work with we are awaiting your response in regard to the parts that you need. I am not finding anywhere that any follow up messages have been sent, or received. We remain more than happy to assist you, and perhaps messages that you have sent are not being transmitted? How were these follow up messages that you mention sent? I was not with the company in 2009-2010 and Charles can add to these responses later in more detail. In the mean time we are available to assist in the ticketing system.

As one of our team members posted, the OP was indeed speaking with Jake and was passed on to my Operations Manager, Stephen, who did reply immediately as shown above. At no time has the OP made any request of Jake nor of LN. For those of you that maybe don't have the virtue of having been doing this for decades, JE did have a problem with several forgings cracking like this, but those were all on aircooled Porsche engines. This would be the first time we've seen this on a watercooled Porsche engine with this particular forging from JE. Please don't think I'm singling JE out on this, because I'm not. I've seen CP and Wossner pistons suffer similar failures, but it's far and few between. Based on the OP, the engine did not exhibit any symptoms or issues prior to this failure. Being that the car was just pulled out of storage, I see two likely reasons for this having occurred - bad gas or failure of the knock sensor, or a combination of the two. We are seeing more and more cars with wiring harness issues and rodent damage is just one of the problems, let alone simply the age and degradation of the harness over time. Even recently we had shop we work with have to repair the wiring to the knock sensor since a rodent had damaged it. Also, in years past, we've seen knock sensors go bad, with similar results. Either or both bad gas and a non-operational or malfunctioning knock sensor can and does lead to pre-ignition and detonation and lead to failures. As no one at LN has had any dialogue with the OP, all I do is speculate at this time as to the cause based on decades of experience and literally thousands of engines that have been rebuilt with Nickies and these same JE Pistons. To answer the questions asked about the OP, we have never used iron liners - they have always been aluminum. With regards to clearance, had that been an issue, the engine would have sounded like a diesel and would have been smoking and burning copious amount of oil, as with the FSR piston having a smaller skirt, this would have magnified the issue. Measuring the pistons after the fact is likely not going to tell you anything as they are damaged and the skirts are likely collapsed. I would like to see photos of the pistons showing the whole side from the top ring land to the bottom of the skirt (on both sides, for all of the pistons), as photos of that were not shared. Also, since there is mention of selecting new pistons, what specifically is being done to the block?

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From a proactive maintenance perspective, should we consider replacing the knock sensor? What is involved? Is it a DYI? Thanks for your insight.

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If you know where it is, you would not ask that. Yes, it's DIY but only for really serious DIYers.

A knock sensor is a solid hunk of a piezoelectric crystal. I have never heard of one failing. Besides a NA car shouldn't be hanging on the knock sensor anyway.

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I have.

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I bet it works to spec even with the cracked housing. The ones I have had with cracked housings always have worked correctly. I should have written "without setting a code".

So what was the root cause of this failure determined to be ?? Failed JE pistons or was the pistons damage the collateral damage.. ?? Either way the finger should be pointed at JE or what caused JE pistons to fail..... I don't know of anything an engine builder could have done wrong that would show up 15 years and 25K miles later as failed Pistons... Have you bench tested the AOS ??? Send it to me .....IF it was experiencing partial hydro-lock that could explain it all !!!!

OP is a one post wonder. He posted the initial post and disappeared. Looks to still be active on the forum though, last accessed yesterday. -Tom

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Well when the first answer to your post questions your legitimacy and the capabilities of your mechanic �

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I've seen the wiring also be the failure point, not just the sensor. Mice and age. Gotta love that modern soy based sheathing (the mice sure do!)

Its obvious that extremely high cylinder pressures were encountered...Enough to break/crack the piston skirts ..( no other internal damage reported that is not collateral) Knock Sensor failure or Detonation or pre-ignition will shows signs on the top of the Pistons and spark plugs.... With it having Carrillo Rods and Nickies Cylinders with extreme cylinder pressures the "weak link" would be the piston skits ... I have said it and seen it before many times, this " unexplained failure" the AOS is never suspected because there is so much visible damage and oil is everywhere as in these cases ... But is simple enough to eliminate the AOS for the scenerio,,,,..If the AOS is GOOD, then it didn't cause this failure,, but if it is BAD it is the "smoking gun" ...

How would you bench test the AOS?

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I use 3 tests, it has to pass all three tests on my bench 1. flow test : flow air through the AOS when diaphragm open to see if it can flow 300 LPM 2. Diaphragm test : plug off all ports and apply 15psi pressure to diaphragm and check to see that no leaks/air is coming out of Atmospheric vent port 3. Control test : plug all ports and Apply 29 inhg to close diaphragm then release lower port to see that diaphragm controls flow Test #2 is the one that usually fails

Well,,, my 2cents... Don't see any signs of pre-ignition or detonation in original piston pics above.. I'm a deto preign expert... unfortunately...lol If pre-ignition or detonation were there, the top edge of the piston would lose its sharp edge. Would have signs of erosion on that edge and possibly on the piston crown, maybe with some melting on crown. Don't see any of that in the above pics at all. That piston edge looks sharp still,, too lose that 'sharp' edge is usually the first sign of deto/pre. Might be something to PT3 suggestion of oil ingested hydrolock from failed AOS. That certainly would explain the damage on the piston cracking/splitting big chunks off its crown and side. Wonder if rods were measured for bends..? Could be 2 things happening here simultaneously... hydrolock and defective pistons, because,, not sure how some of those cracks could happen from hydrolock, but maybe..? The cracks in the piston skirts could also be from the piston rocking in the bore from oil on one side of combustion chamber/piston crown...? Over-revving or putting the engine under excessive load can lead to cracks in the piston skirt. Or maybe these pistons were part of the bad batch of JE pistons that did crack their skirts and pin bore boss. A period in the mid-2000s &(2009/2010) where JE Pistons experienced some failures, particularly with 98mm pistons in the wrist pin area and some larger displacement applications. But iirr those happened quickly in built engines, they didn't make it 25,000 miles, not even close iirr... I'm leaning towards oil ingested hydrolock at high load/rpm/with a money shift sometime in engines life.... BOOM. jmo

^^^^ Yep , it would be simple enough to eliminate the AOS as the most likely cause by "comprehensive bench test " ... But I have a feeling this thread will end up like the hundreds of others that had inadequate Forensic Analysis and be left " open ended " ......

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Look at post #1. A large chunk of the piston crown is missing. This is a classic sign of preignition.

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Are you talking about this picture with the big notch on the top ?? That is not a broken piece, that is just valve clearance notch ...

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yes, thanks! Wow I did not realize the valve notches that far down into the side of the piston. I agree with everything you said, the AOS would be one of the first things I looked at but we will likely never get to know. Highly unlikely that anything the engine builder did could be the cause at this point.

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Yes but like I said, the AOS is hardly ever suspected due to such visible carnage and OIL is EVERYWHERE !!! ..... Only careful Forensic Analysis can put the puzzle pieces together .... I think the OP really didn't want to know the root cause and was hoping for some financial help in an "Unknown Failure" situation ..

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That�s a very thorough test. It could be useful to test a new unit before installation. Thanks, I bookmarked this!

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No Need with the UAOS System...( different tests) .. This is just for Forensic Analysis of the frail OEM AOS ... .....

Yeah, if only Porsche designed a better AOS and IMSB; and gave better advice on changing the water pump and oil more frequently. If they did, we would have nothing to talk about here on the forum as the cause for M96 engine failure. But yet, the Porsche aftermarket community developed cost effective preventative solutions and procedures to the address the factory weak links and we still argue about it. OP, sorry about your engine failure. You would do yourself a big favor by taking advantage of the red carpet that has been rolled out for you by Charles, Skip and the rest of the experts.

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Actually its much much simpler than that. All Porsche had to do was use the same engine in all 996 cars. Leave the Boxster with the m96 it was designed for. Use a slightly de-tuned no turbo Mezger(325hp), same base engine block/head the 996TT, or 996GT cars use. The slew of bean counter catastrophic problems of the m96 disappear with the Mezger. It really would have changed everything. More than likely the Porsche 996 engineering development team did request the exact above thing, but its obvious the bean counters won out and left us holding the bag of $hit. Although for some of us, that bag of $hit turned into a giant pot of gold at the end of the m96 rainbow

Big market and big opportunity for enterprising entrepreneurs to develop more solutions. Over 350,000 M96 powered Porsches tooling around the globe.

I think it's because the Mezger cost to produce is far higher. Having owned both M96 and Mezger, the Mezger is unquestionably a better engine but there's no free lunch so the downside is it also costs a lot more when things break.

I never had a problem in concept nor in operation with the M96 engine over my 23 years of ownership. Its been a great engine that is durable as he'll on the street and track. But as I mentioned, you gotta upgrade the AOS and IMSB, as well as replace the waterpump every 5 years and run great oil and change it a couple of times a year. Or you will be an unhappy camper. Not rocket science. But what I really like about the M96 is that it can be rebuilt with bigger bores, top of the line internals and enhanced headwork, creating a powerplant that can push substantially more power than the GT3 engine with incredible durability. No complaints what-so-ever.

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lol..it's a popular theme to re-write history, but to fully understand the m96 you have to forget the word Mezger .....( for the time being )... Hans Mezger had nothing to do with 996 Carrera, Gt3 or Turbo.........He was retired in 1994 and for his last 35 years was only involved in F1 Racing engines....( ie. the 753 Flat Eight 1.5 liter 177HP engine ... and it's predecessors in the 917 and 935) ) Hans did get credit for developing the first Flat Six for the production 911's in 1963, but honestly it was a continuation/development of Porsche's 1939 Type 1 Flat Four VW engine...( they all have the same 4 bolt bellhousing mounting)........ The Porsche Flat Boxer engine was available from 1.0 to 4.0 liters from 1939 to 2011...way before and even after M96....( and even the 2011 Porsche "Mezger Style" engines had issues I could go on about) The M96 should get credit for making "Mezger" a household name ....lol The 996 was designed and developed before the Boxster, but the Boxster was release to the public first... Yes they both were built to a "price point" and with the Boxster being released first, then the 996 coming along with the exact same look to the front end caused the 911 purists to condemn it...... But they both sold tons of cars due to the looks handling and performance, but new Porsche owners both experience oil leaks from the Rear Main Seal that Porsche replaced the engines after a couple new Seals didn't stop the leaks....After 6 revisions of the Rear Main Seals Porsche stopped the oil leaks but the consumers had already condemned the 996 and Boxster..for having to have new engines ( this was even before any IMSB issue) ...and Values fell to rock bottom and took 996 Turbo with it ( not many Gt3's were sold so they didn't count) ...I remember I could have bought a one-owner 2001 Turbo with less than 50K miles for $29K from the Porsche Dealer !!!! ........ Then the word "Mezger" started to be used more and more as a way to keep the 996 values down and to get higher prices for the Turbo and GT3 variants....until here we are ..... Before then not very many even knew who Hans Mezger was ....

Agree. Mezger pretty much became known as "doesn't have M96 problems". He didn't develop it but it got his name because it bears his architecture. IMHO it is one of the best water-cooled engines ever made of any make, nearly bulletproof. Mezger does have other problems like any car always will (spun camshafts, coolant lines) but nothing that will brick an engine. I have seen Mezgers with over 300K miles. I bought a 2002 Turbo with 60K miles for $38K and got a $2K credit. That was back in 2013 and everyone was obsessing over the headlights on the 996, saying it wasn't purist and they just couldn't. I find people like this dramatic and silly. Like I care about the headlights.

They should be worrying over the taillights.

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Honestly it's been so long since I've seen an AOS pump oil into an intake and cause a failure, that it really didn't come to mind.

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Is it really his architect ? All Porsche Flat engines up untill the M96 use the same 4 bolt pattern ....To me this same bolt pattern constitutes same engine family.. From the first Type 1 in 1939 by Old Man Porsche, then the "Fuhrmann Engine" in the 1950's as the first Over Head Cam Flat 4 , then Hans just added 2 more cylinders in 1963 and other Porsche Engineers did all the rest....BTW in 2010 the GT3 got some lightweight Aluminum bolts in the Vario-Cam Vane adjusters that didn't hold up well at all and caused some catastrophic failures.... I agrees on the headlights, to me they were so much better Aerodynamically than the "Bug Eye" headlights of the Air-Cooled ones... And because they were "Non-Mezgers" I could buy two of them ....

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@Charles Navarro Yes it didn't come to me right away either.......I just keep thinking "What could cause these Piston Skirts to break ??"'..........and when I kept running into dead ends it dawned on me...the frigging Stock AOS is 15 years and 25k miles old !!!!! I think AOS issues have caused so many bent Rods and Cracked Cylinders its unreal....But with this one having beefed up Rods and Cylinders the next "weak link" is the Piston Skirts ....

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I'd also bet that most people are used to upright engines, which typically just don't have as much of the oil control responsibility placed on the AOS. BMW V8's for example are notorious for AOS failures but all you see is a plenum full of garbage and lots of blue smoke.

I have lost count on the number of times I have been at the track over the past two decades watching guys with a M96 engine blow smoke plumes. I tell them what's happening with their AOS, why its happening, why they needed to get the Motorsports AOS way before the UAOS was designed, and now why they need to get the UAOS Track. Funny thing is that a good number of them just replace it with the factory AOS again because their indy doesn't understand the issue, or they don't understand the issue, or they just dont want to spend the money on a better AOS. But yet, its such an easy fix...

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The Mezger has a much more modular design than M9x. If you look at the differences in the cylinder head, M9x has fewer castings, requiring fewer gaskets and bolts -- it is a more integrated design. Looking at the block, M9x is also more integrated -- cast in place cylinders, etc. Mezger is basically a true racing engine that could be torn down and made new after each season if you were so inclined. But now that you mention it, you are right; calling it "Mezger" is really a misnomer. Agree. My M96 would blow smoke at the track. Usually after it was driven hard and then the engine was started again. Fortunately nothing bad ever happened, and that was back when there was no UAOS. The first time it happened I thought maybe I had overfilled the engine with too much oil.

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Exactly !!!! ......The upright In-line and V's have Gravity on thier side helping in the oil control.....whereas Flat engines use the lower " Center -of - Gravity" of the engine to aid in handling, but this also places more burden on controlling the oil movement.inside the engine ... Very true , and with Porsche then lowering the oil level to help stop the smoking just increased the Spun Bearing /thermal runaway events.. Its been debated a lot as to what or how much damage occurs from the smoking vs Hydro-lock, but @allcool brought up something he learned in Engineering Experiments that it didn't take a full hydro-lock to cause damage....a partial hydro-lock ( smoking) can cause cylinder pressures to get high enough to cause damage before full hydro-lock occurs.. This is what we see on this engine ....

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I had two factory AOSs go on the track, same spot on a carousel, one right after the other back in the mid 2000s. I was lucky that I was a novice and wasn't that fast. Also lucky that I could get off the gas and off the track quickly as the carousel was ending. Yep sheer luck or I would have hydrolocked. Then I got smarter. Just because it was a porsche didnt mean that it was bullet proof. About that time the Porsche factory new that had a problem with the AOS so started to recommend running the oil level a half a quart low, which didn't help with oil starvation. Not a big deal with a novice driver, but a very big deal with an advanced driver. It was then that I went to the Motorsports AOS and 2 qt deep sump. Certainly better to run 10 quarts if oil versus 8 quarts in the M96. Also started running Millers Nano. But the key is to run an AOS that can safely process more oil than the Motorsports AOS with a bigger diaphram, which is what the UAOS Track can do. I now run 12, really 12.5 quarts of oil between the UAOS and 2 quart deep sump. No smoking, oil pressure drawdown are mitigated, engine is happy, and no risk of hydrolock nor intermix from AOS failure. The M96 is so damn easy to keep running by upgrading the AOS, IMSB, Sump and keeping the water pump and oil fresh. Same applies to every rebuild. You may have bigger bores amd better internals, but you still have to upgrade and refresh the same key bolt on parts. But many dont want to take the time or spend the minimal amount of money to mitigate the problems. Dont know why.

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For sure, i would argue that the AOS and water pump account for more engine failures than the IMSB which looks to be right under 9% according to the RL Poll. The reason is that many have upgraded their IMSB over the years, but the majority of 996 owners still dont understand the AOS amd water pump issues and how easy it is to fix.

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Yea the development of the M96 has came a long way ...especially in the last 5 years since I retired and have had time to fix/design things ...lol ...( pat self on back)

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Keep fixing and innovating please!

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Yes, strong work. That's kind of what's special about this car. Some in the community have contributed to improvements and advancements of these engines in a meaningful way beyond what I have ever seen with any other cars my father and I have owned.

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I'd like to but my health sucks right now ......

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Best wishes to you in every way possible. You are one of the most knowledgeable and best posters I have come across. Every Porsche tech on the planet should aspire to one day have the same level of knowledge and understanding that you have attained.

We can thank the aftermarket developers for inventing and discovering more superior bolt on solutions and procedures that keep the M96 running. Skip, Charles, Jake and Hartech can take credit. 3 Key Product Developments 1. IMSB: LN Retro then LN Solution 2. AOS: Motorsports AOS surpassed later by an upgrade to the UAOS Track 3. SUMP: 2 Qt deep sump or upgrade to the industrial strength UIDS. There are four key maintenence procedures discovered through the years that keep the M96 running. 1. Water Pump: change it every 5 years 2. Oil: run high quality oil with high viscosity and change it at least 2x a year. If your tracking the car make sure its very high viscosity and temp resistant. Make sure its fresh before you go on the track. 3. AFR/Other: keep your fuel injectors, oxy sensors, coils, plugs and MAF fresh and functional. 4. Proper start up amd go procedures. All pretty easy. All apply to the factory M96, factory short block swap and a rebuild.

Given the cost of these maintenance items and upgrades, I can understand why people balk. Nowadays the 996 and 986 are considered entry-level Porsches and could be had for roughly $20k. To address those items, with labor costs included, is another $10k. People can�t fathom putting in an additional 50% of their purchase price, so they�d rather risk the consequences. It�s like the Miata kids opting for the cheapest coilovers because the good products cost more than their car. Then they wonder why they bounced off into a tree.

They are missing out on one of the greatest drivers cars that can be had for pennies in the dollar to original cost. Not to mention purchase price plus all the refresh items, even including the cost of a rebuild is damn cheap in relation to other sports car opportunities.

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Yes very true .....but what do you call someone wanting 996 GT3 performance from a 996 Carrera ?? ( Without spending much $$$)

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Absolutely agree. This car punches well above its weight even when the extra costs are considered. I probably shouldn�t say�

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You can say it .....Everyone has their big boy pants on in here...lol..... I call them Dreamers....Nothing wrong with Dreaming as long as you take steps to make the Dream come true..... but Dreaming from the couch with no action is foolish thinking ....

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What are you saying exactly? I don't believe I've spent a fortune, probably much less than a lot have who's car will never see the track. I regularly hang well with GT4's GTS's even some GT3's. Lets face it regular GT3's are not that special. You need to spend a lot more on them than I have to make them really track worthy. Cup cars clubsports, they are real track cars.

You must be wringing every ounce of speed from your car if you�re matching GT4s and GT3s with our power deficit - which I assumed was what�s meant by �performance�.

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Mostly making the comparison with stock gt4 and gt3s. Yes on the straights they definitely have the advantage. Not saying I�m always faster just not getting my doors blown off. Was on track with my friend in his 991 gt3 today. Track without a big straight and I had 4 seconds on him. We are of similar experience. If you don�t waste your money on the things that make no difference you can have a formidable track car for a reasonable cost. On the street what�s really the difference in a C2 and a GT3?

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You are doing the right thing .. I am just saying those who buy a 25 year old low mileage bone stock Carrera and want to keep it all Original Porsche and fill with 8.25 qts oil ( half full on the stick).of 0w-40 oil as the "Internet Wisdom" suggests, but then go to HPDE or Canyon Carving with expectations of not having any unpleasant circumstances of oil pressure/control issues...

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Thanks, thought I was doing it right, happy to get the Skip seal of Approval!

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A bit off topic, sorry. The UAOS was not "...such an easy fix" for my all-thumbs DIY work but persistence and help from Skip sorted me out. @Porschetech3 is one of the folks I follow most on RL! Can't thank him enough for his contributions to the community.

Dont know if anyone has seen this in the UAOS thread. Skip also has a non-emmisions compliant version of the UAOS as well. It can process even more oil. My indy was putting them on a couple of race Caymans. As soon as i walked in the shop this spring, the tech was pretty excited and said hey, take a look at this! Pretty cool.

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That looks like it belongs on a Mac truck!! Two gallon capacity?? That ain�t gonna fit!

I'll bet a non-emission compliant race car will have a lot more room than the street car.

I replaced the AOS two years ago.

I replaced the AOS two years ago.

:фейспалм:

Two year old AOS can still fail. Makes sense to test it if you want to rule it out.

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There is nothing funnier to me about NA/NB owners bitching about the cost of coilovers when the equivalent of Xidas on a 996 would cost $5k There are so many moron Miata owners who don't know exactly how good they have it.

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No.. I'm pretty sure the plentiful nature of catastrophic failure modes for the M96.0 + headlight supremacists (I still think the 996.1 is one of the best looking 911s full stop).caused your valuation problems. It's great that there are partial fixes and greater understanding of _why_ M96.0 has these issues but the idea that somehow the valuation gap all comes down to some false perception is laughable. M96.0 is not a reliable motor. Saying it is reliable after taking x-y-z precautions and replacing parts with aftermarket units does not fix the state in which the engine was delivered to the consumer.

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No I was there ... I saw it first hand ...I was good friends with the GM and we were both astonished at how the Values dropped so fast on the 996...but yet we were still selling brand new 997.1's ( with same engines) at full Retail value ...lol perception..yes... I'm telling you the Values dropped like a hammer even before the worst of the engine failures had happened...lol

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If you've got an early 996 (98) then its the lightest 996, cable throttle etc. They were basically as fast as a first gen GT3 due to the power to weight (A GT3 was quite a bit heavier). Now add tires, coil overs, a decent suspension setup and remove even more weight from a base Carrera (maybe rear seat removal and race pipes) and you have a GT3 beater for not much $$$

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Exactly !! Documented right here has been several Genuine AOS's fail right out of the box !!!

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No, but it sure does fix the problems.

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So many motors are not reliable! Look at GM's latest crisis, or BMW with oil surge issues or Fords with wet belts.....a lot of these have fixes, some don't! Either way the M96 is not as bad as it could be, and there are plenty of high milage ones, if a few small fixes can dramatically increase its longevity then I'm all for that. Even better if people don't want to pay for it, I'll happily pick them up and fix them myself!

Nothing wrong with the M96. Whats wrong are a few bolt on parts that should have been upgraded from the factory. And all are easy to fix with better aftermarket parts and replacement procedures. 1. IMSB 2. AOS 3. WATER PUMP But the factory did mislead us on oil change frequency to protect the bores. But here again, we have procedures that work and substantially better oil today than Mobil One. For sure, the factory dropped the ball on oil starvation and oil pressure stability on the track and canyon carving. But once again, we have aftermarket solutions that work I have slept well at night for 23 years of 996 ownership.

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^^^Bingo. In addition to the GM, BMW, Fill In The Blank Manufacturer, look at all of the problems the 997s, GT4s and 991s are running into. Its only a matter of time before the 992s get hit with some fun and excitement. There isn't a car produced by any manufacturer that doesn't have issues that need to be solved for. Just the way it is. Good news is the M96 has been around for 25 years, its issues have been identified and all can be solved for very easily.

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@Vladimir754 I'd be glad to test that AOS for you N/C ......just to be thorough on the Forensic Analysis....

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I like to take this to the conclusion that all cars are bad. Off to ride my mountain bike

What a ridiculous thread. I call troll. Zero interaction by the OP. Only inferences to start and bumping when the conversation dies down.

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I am impressed with the role of the AOS in the M96. I just want it to separate oil from crankcase vapors and add a bit of vacuum to the crankcase, not kill my engine. Does the UAOS provide any safeguards from mortally wounding the innocent engine?

Quotes source post: 20131889

Yes ...the UAOS System is 4x more efficient at keeping oil from entering the engine.... This 4x increase in efficiency also allows for 1 extra quart of oil to safely be ran in the engine to help with oil starvation on high-G turns also .. AND the UAOS System has a Warning System ( an Optical Infra-Red Microprocessor Controlled Liquid Sensor) that will "Slow-Flash" the Warning Light above the Temp Gauge if there is any significant accumulation in the Accumulator...

Quotes source post: 20131791

Me too...

Quotes source post: 20131943

I prefer stock/OEM unless there is a clear case for a modification. This just put a UAOS on my Fall maintenance list before she goes into hibernation.

Quotes source post: 20132664

Right ....If everyone knew what I know about the Flat Six M96 , No-one would EVER put a Factory AOS on it....

Quotes source post: 20133794

So would you say the LN UAOS is the only reasonable way forward? What other options are there? How about hypothetically speaking if you aren�t worried about emissions?

Quotes source post: 20133897

I see you are new to the 996 Forum ? You have lots to learn Grasshopper ... Yes the UAOS System is the only reasonable option that makes sense... For a Street Driven /Tracked Car nothing else needs to be considered... BTW , I am the Patent Holder/Inventor of the UAOS System...and UIDS .. ( pat self on back )

Quotes source post: 20133995

Yep, new to forum and to water cooled Porsche ownership. My car is a Cab and I don�t see any situation where I would be tracking it. Mostly bought the 996 to be a daily driver and take on some road trips so reliability is important. Will be meeting with a Indy mechanic next week to go over new IMS, AOS, etc as the car hasn�t been driven much up until now. I had heard reference to some variety of non emissions compliant AOS as well and am curious about that.

Quotes source post: 20131859

Funnily enough, a lot of good discussion has developed from this thread.

Quotes source post: 20134604

Even a street car can benefit from the UAOS because if the AOS fails, it costs a lot of pain and suffering labor to get to it. And street cars can injest enough oil - doesn�t take much - to hydro-lock the engine and damage it. The Porsche mechanics by me (Chicagoland) install UAOS. It�s rare for any mechanic to deviate from standard OEM-designed parts unless there is good reason, and this is one.

Quotes source post: 20134662

Quite true. Any time we get into a ramble, there are good bits of information. I just have a problem with how the discussion started with a non-involved op throwing some unsubstantiated inferences around. Even to the point when LN shows the data on communications, there is no response. This is a bad actor. And another weird thing about the op, the join date is 2017, but they had zero posts until this thread 8 years later. How does that happen? How many people have joined a forum and not posted the first 3 to 5 posts immediately? My conspiracy theory brain says someone from Rennlist must be involved to make the 2017 date happen. Maybe to start a discussion, maybe to try to knock LN. It reminds me of that BS post on Facebook. My comments on the UAOS is that every street car, whether tracked or not, should have one. It makes the diaphragm simple to change out if it ever breaks, the length of pipe and IR sensor give warning to the diaphragm going bad. And then the track drain was added allowing a higher oil level so the oil pump will pull less aerated oil and the oil temps will take longer to saturate(on track). It's pretty amazing. The next better step is a AOS open to the air...

Haha, nahhh. There�s no reason for Rennlist to want to **** off one of their major sponsors. This place has been very welcoming to open discussion. As for the incorrelation between join date and posts: I�ve seen a lot of accounts like that here. I suppose they�re all shy, or may have registered an account only to download some attachments or do some other activity that is limited to registered users.

Quotes source post: 20135773

It happens. I was a paying member for 7 years before I made my first post. I was/am here for my own research and info to gleam. Not much interest in the other nonsense. This is the only platform I associate with that could be considered �social media�. That stuff is the rot, which is unfortunate. I agree with your sentiment on the OP though.

Quotes source post: 20135826

Agreed again. It doesn't make sense for Rennlist to be involved. That's why the comment exists as a conspiracy theory. Conspiracy theories require that you suspend belief to make them work. Also agreed that some folks are shy and don't have alot of experience writing out issues that may be new to them but understood well by the group. Our responses to these folks will be the same as with anyone, alot! But, that's easily defused with a simple, "Hey guys, I'm not a frequent communicator, so help me out" comment. Also understood that this kind of comment is very hard to write for a shy person. We've seen many cases of folks with different primary languages say the same thing, and the discussions go very well. Reading back through the first post, it seems the OP is outside of the US, and trying to create a contact with LN. I expect that has happened and the value of discussing on Rennlist, for them, has gone to zero. Too bad for us. It would be nice to know how an older reconstructed low mileage engine has failed. It's something we need to learn about.

Quotes source posts: 20134604, 20135773

I do make a "non-Emission Legal " Track Only version of the UAOS System that is "made to order" on request only .... It has all the features of the UAOS Track ( ie. 4x efficiency , dual oil drains. IR warning system, billet Aluminum Accumulator) but it adds another Accumulator and Atmospheric Dump ... The Atmospheric Dump makes it Illegal Emission wise and NON-Street-able due to oil changes need to be a 500 miles.. due to blow-by into the oil and lack of vaccum to aid in clearing exhaust/blow-by gasses from the Crankcase... Re-posting this from another thread post :: An improperly designed/functioning Crankcase Ventilation System ( PCV/AOS ) can cause Sludge as well as too long OCI... Blow-by Gases contain Oxygen and Water as well as numerous harmful and harmless gasses that if left to condense with the oil will cause Sludge to form.. On some engines the PCV/AOS System doesn't do a good enough job of removing these gases to keep Sludge from forming even when using the recommended OCi..( Audi 1.8 and 2.0 I'm looking at you ) And of course if the engine has "excessive Blow-by" this will need even shorter OCI's to keep Sludge from forming.... The stuff that is in Blow-by besides Oxygen (O) and Water (H2O)........... Carbon dioxide (CO2) – Carbon monoxide (CO) – Nitrogen oxides (NOx) – Sulfur dioxide (SO2) – Hydrocarbons (HC) – Benzene (C6H6) – So, the AOS/UAOS is important not just to keep oil out of the Intake, ( and to keep from having oil starvation with UAOS ) but also to keep theses gases from condensing in the oil and forming Sludge... This is from 987 Track Only ....NOT for street use... BTW, the additional Accumulator is not a 2 gallon,lol.. it is .5 liter..( must be a Camera Trick from a Fisherman )

Quotes source post: 20114059

As a person who works at the other car company 2 hours east of Stuttgart, I can tell you that all car companies are managing BOM costs. Otherwise, we'd all be driving Paganis . Well, even Pagani's engines are build to a cost. heh. It's frankly amazing to me that we are able to drive such machines at the pricing we get given the effort, time, people and people that go into creating and manufacturing them. Avg cost of development is about $2-$4B per model over 4 years, give or take. Too bad I couldn't import my C4s here as it would not please T�V. Ironic.

Quotes source post: 20109322

Ever since the rebuild, the engine’s had a cold start rattle — sounds like piston slap — and there's blue smoke on startup. It clears up once the engine warms up.

That's not even the same engine as post #1 .....what the f**k ??? Do we have a Super Troll here ???

Quotes source post: 20154793

Hey, Russia didn't interfere with the election...lol

Nevertheless its a good thread... Even if it was a BS initial post.

This is one and the same engine. I'm not trolling—I'm the actual owner. Let’s keep it respectful here. Also, why is Jake silent? He built the motor. And for the record, Charles Navarro ask for photos of the piston skirts. I can post a video if needed.

Quotes source post: 20155991

Jake no longer reads or posts on Rennlist, so that's why.

Quotes source post: 20155991

Because Jake hasn't been on Rennlist for something like 3 years. If you wanted a response from Jake the appropriate channel would have been to continue to work through the support ticket that you opened up with LN Engineering

Quotes source post: 20154520

The reason I asked for photos of the skirts is because that tells the story. The wear looks even in the abradable skirt coating. I'll address your other points: Piston noise. Forged 2618 pistons are noisier than a 4032 piston. The FSR forging, while providing reduced friction with it's box skirt design, isn't as quiet as a full-round slipper skirt, which is what we have been favoring for many years. Smoking at startup. Factory pistons have pinned second rings, which prevents the gaps from ending up at the bottom of the bores. No aftermarket piston manufacturer offers this. The reason why this matters is the 2nd ring's main job is oil control. It is not a compression ring. If you look at an aircooled Porsche, they almost always give a puff at startup. There are other contributing factors, such as how the cylinders are honed, AOS function, injector function, oil quality and condition, etc. This is not a complete list.

The information provided above is independently confirmed and corroborated directly from JE Pistons: https://www.jepistons.com/je-auto-bl...al-differences One of the key differences between these two pistons is the 4032 has a much higher silicon content (12.2% vs just .18% on the 2618). This means the 2618 will expand ~15% more than a 4032 and this is the reason they will be slightly noisier when cold as you have noticed. Front side relief (FSR) foraging designs have a reduced skirt width which helps minimize the piston contact with the cylinder wall. If this were my engine I would take Porschetech3 up on his free offer to test the AOS. It is common knowledge among those in the know that a new OEM AOS can be faulty right out of the box and many high end engine builders have even created their own AOS testers as a result of this problem. I can't think of anyone better to test your AOS than Porschetech3 given his in depth and extensive experience (creator of the UAOS, etc). If you really want to understand why your engine failed you are going to need to perform forensics and this is a good starting point.

Quotes source post: 20155991

@Vladimir754 I offered my very plausible hypothesis of the root cause of the Piston cracking failure and a Free Test of the AOS to confirm..... and was ignored... IF you really want answers you need to accept the help in getting them ... A failed AOS that causes hydro-lock or partial hydro-lock usually results in bent Rods or cracked cylinders,,, but since this engine had upgraded Rods and Cylinders, the Piston Skirts are the next weakest link ...( there is always a next weakest link ) This is not the first and won't be the last engine to fail from a new or fairly new Genuine AOS ..... Oil is the Life-Blood of the engine but an engine can also "Drown" on its on Blood......This has happened hundreds and hundreds of times but is not normally understood due to the "blood" is everywhere ...

Thanks for offering to help test the AOS. I already checked it myself using a Testo differential manometer, and the AOS is working fine.

I�ve been doing business with well-known American companies like APC since 1992, and I�ve always been impressed with their trust, quick decision-making, and commitment to their reputation � unlike many European companies. I�ve often used this as a positive example in business. Now I�m disappointed. Unfortunately, when I asked for help (not for free), I got a stream of excuses and blame instead. At the start of this thread, I asked three questions and only got an answer to one of them. Right now, I can�t and don�t want to send the block to LN. All I was asking for was advice on selecting pistons and diagnosing the failure of the JE piston. I�m very disappointed. If I�m wrong, I�m willing to share my corporate contacts if LN or Jake are willing to help. This will be my last post. Hopefully, this post will be useful to anyone who thinks twice before choosing a shop for a rebuild.

Quotes source post: 20177053

Here is the kicker... Even if the factory AOS's diaphram hasn't failed and is "working fine", its not working fine. The reason is that it lacks the ability to properly process the oil. This has been admitted by the Porsche factory resulting in... 1. Porsche telling everyone to run less oil in their engines to mitigate oil getting into the intakes, and 2. Porsche then developed the Porsche Motorsports AOS as a more robust solution to the suboptimal factory AOS in keeping oil out of the intakes. Then along came the UAOS which was substantially better than the Porsche Motorsports AOS because it could handle running and processing even more oil quantity in the M96 than can the Motorsports AOS, which further solves for oil pressure and oil starvation. Not to mention it solves for many other issues that have been discussed on this thread and others. Even though an AOS may not have failed, it actually has failed on day one due to its inability to process oil which causes a boatload of problems on the street and track. Its a tough concept for many to get their arms around. Good luck with your next steps. But regardless of what you decide to choose for pistons, get yourself a better AOS so you dont have the same problems again.

Quotes source post: 20177074

Sorry you are disappointed and genuinely sorry you had an engine failure. But you will share corporate contacts...? if you're wrong about what? I don't really understand what you are getting at here. It's been difficult to follow many of your posts like the one above with two pictures including a hand sketch but no other information. People have offered to help like fully testing your AOS but you have ignored that. Per the information you provided your engine was rebuilt 15 years ago . What exactly are you wanting from LN or Jake? Charles told you the model number of the piston they currently favor. For diagnosing the failure we have already stated several times it would require forensics; otherwise just sitting here posting these messages every few weeks complaining, you aren't getting anywhere if you are actually trying to understand the root cause of your problem, which is what you need to be doing. I am sorry this happened to you but if you were just looking for advice from LN, you should have just followed up on your ticket that you submitted with them. To be honest I have always known Charles and LN to be extremely generous with information. I am sorry this happened to you but I am not sure what else there is to say here.

Quotes source post: 20126480

[Image-only post; no author-written text. Original image references:] https://rennlist.com/forums/images/smilies/facepalm.gif

LN provides support for FSI engines now. But I wouldn’t expect it to be free on my 2 year old build, much less a 15 year old one. LN has always responded quickly to my tickets, even on weekends. 1) Check your spam filter. 2) Make certain you entered your email address correctly. 3) Send another ticket.

Quotes source posts: 20126452, 20177053

So, this engine has had (2) Factory AOS's on it in 25k miles since the rebuild ??? The Test Equipemnt you used ( Testo Differential Manometer ) is NOT the right equipment to use to bench test a AOS post mortem.....I already explained the test proceedure I use for "bench testing" an AOS for Forensic Analysis.... What proceedure did you use ?? With this being the "Second" Brand NEw Factory AOS in this engine its very very plausible that the Engine suffered damage during the failure of the "FIRST" Brand NEw Factory AOS....( first being installed 15 years ago then failing 2 years ago ---when second was installed 2 years ago)...and very likely "cracked" the piston skirts during a smoking/high cylinder pressure event ....(why else would you have replaced the AOS at that time ??) And then these "cracked piston shirts" kept growning ( un-noticed) until one "finally" broke completly off the piston and caused the very noticable symptoms.... I understand your dissapointment in haveing an engine failure , but not the "facepalm" and finger pointing at Jake and LN........the finger-pointing should be at Porsche/Mann+Hummell and the frail OEM Genuine Porsche AOS System.....jmho There is no way you can convince me that 6 JE Pistons were defective in a way to crack the skirts...or that they could be installed in a way to cause the skirts to crack.....the cracking was caused by extreme cylinder pressures during an AOS failure event after 13 years ......

Quotes source post: 20178104

Sounds like a very plausible scenario. If he really wanted to know what happened, he would have already taken the opportunity you offered, to have the World's m96 AOS expert check his aos properly. If not to just to rule it out.

Quotes source post: 20178205

Yep, the OP doesn't want to blame his engine failure on the Porsche/Mann+Hummell's frail AOS System......even though that is by far the most likey cause.. Back 15 years ago when this engine was built, it was well known of all the failures of the OEM AOS,and is why FSI would put NEw OEM AOS's on all rebuilds., but not well known of all the colateral damage that could occure.. As to me being the worlds Expert on m96 AOS, hell this is what I have done since 1974...( 51 years ago )...lol....I went to work in a Dealership at 18 as a "Tune-up Man"... Way Back when you got a tin can like a Coffee Can that had Points, Plugs, and Condensor in a "tune-up Kit"..... I used a Sun Scope to set the Dwell on the Points and ignition Tiimng,,, then a Carbon Dioxide tail-pipe sniffer to adjust the carburator mixture.........Then after decades the "Tune-up Man" evolved into the "Drivability Specialist" ........

When I bought the car, it already had the upgraded AOS on it. The engine later died thanks to an IMS bearing failure and cylinder scoring. During the rebuild, the AOS was inspected and put back in when the engine went in. About 20k miles later, it gave up (oil cap suction you could feel, plus lean codes). I swapped it for a Porsche AOS — only thing I could get here in Siberia. Oil consumption? Pretty much zero. Never had to add oil between changes every 3–5k miles. The current AOS was tested on a running engine… before its second failure. Out of the three questions I started with, I’m down to one: which pistons should I go with? Big thanks to everyone here for the advice and support — I really appreciate it.

So, now you are admitting to having an "AOS failure" after 13 years ( 2 years ago) that likely cracked several Pistons... The UAOS was not Invented then, so the only "upgraded " one would be the Porsche Motorsport one that has the exact same frail .020" thick Diaphram as the OEM one becsause it was designed and made by Mann+Hummell for Porsche , same as the OEM one.... Do you still have this one ?? The "Internet storys" about it being bullet-proof are not true .....lol..(as you have found out ) And you want suggestions on Piston recomendations ... I suppose you want a Piston that can withstand " abnormally extemely high cylinder pressures" like when an AOS fails ?? I don't think there is such a thing .... ,

Has anyone documented piston skirt cracking on an M96.3 where the root cause was an AOS failure → oil ingestion → hydrolock ? Specifically cases where the piston failed but the rods survived. I’ve seen well-documented examples of AOS-induced hydrolock on M96/M97 leading to bent rods, damaged cylinders, or complete engine failure. LN Engineering and other sources confirm the mechanism: a failed AOS can pull liquid oil straight into the intake, filling one or more cylinders, and under the wrong conditions this can result in catastrophic damage very quickly. There are also forum reports mentioning piston skirt cracks on M96 engines, though most attribute them to thermal fatigue or scoring. I’m curious about the overlap — where an AOS failure was the initiating factor. After the upcoming engine rebuild, I will of course be installing a UAOS as part of the upgrade package. I also contacted JE about the pistons currently in my engine — they responded incredibly quickly with the full specification sheet. The only extra detail they requested was the laser-engraved order number, which is clearly visible in the photo I sent. I’m genuinely grateful for their professionalism and fast turnaround. Background reading: LN Engineering’s notes on oil hydrolock risk with M96/M97, Pelican threads describing AOS failure escalation from heavy smoke to engine death, Rennlist discussions on real-world hydrolock events and piston skirt cracking.

You want to see some colateral damage on M96 engines from AOS failure ? Here ya go ... Bent rods from AOS failure.. Multiple cracked cylinders from AOS failure The Porsche OEM AOS and Porsche Motorsport AOS are both made by Mann+Hummell and have the same thin .020 frail Diaphragm... 2x thick .040" Diaphragm used in UAOS...compared to OEM Porsche Diaphragm The OEM Mahle Forged Pistons are pretty strong also...That's why when you have an AOS failure either the Rod bends or the Cylinder cracks...But if you strengthen the Rods and Cylinders , then the Pistons are likely to crack....If you put in really heavy/strong Pistons, then the Crankshaft will likely Twist.......Something has to give when "abnormally high cylinder pressures happen" unless you design in a "fail-safe" like install a " intentionally weak head gasket" so that if an AOS fails it will "just blow a head gasket" ....lol......But the M96 has some really strong MLS headgaskets... And that is not how engines are designed. They are designed to withstand the Forces and Pressures that are "normally expected " during operation perameters....Porsche really had no idea the AOS was going to fail as often as it has, the way that is has, because they didn't even design it...Mann+ Hummell designed it and were paid by Porsche to do so and I'm sure were given some criteria... Just think of the Pressures/Forces involved....You have the weight of a Rod and Piston moving up a Cylinder with a force of 300+ HP/250ft/lbs at a Speed of 50 Feet per second......... then impacting a near solid/solid wall of oil/air/fuel.....What would you expect to happen ??? (stroke*RPM*2)/12/60=~50 feet per sec

Terrible photos. But in my engine, all the rods are intact. All the bearings could be reused without replacement. The cylinder liners are intact and still have their crosshatch. That’s exactly why I asked the question above.

Let me reframe the question. If any of us was to bore out and rebuild our engines with LN Nickies or Hartechs equivalent, and take the proper step of upgrading our aos to a UAOS w/ Track drain to prevent oil pouring into the intake, what would the recomendation be for the strongest, most durable rods, pistons and rings available today in the market? Something that can handle the street and track. i would like to know the answer as well.

Quotes source post: 20184550

Here is a partial list of normally used high quality rebuild 996 parts. Sure there are custom made parts available also... RODS: In order of my preference Pauter Billet 4340 Carrillo 4330m K1 PISTONS: Keep in mind most all after market 996 pistons do not have locating pins for the rings. Make sure your freshly plated nik'd cylinder is measured for size/oor/taper before you assemble it. Don't let a re-engineered Cylinder you've just spent $$$$ on not be perfect. Check ALL their work yourself. Good reason I say this. If cylinder is not perfectly machined with close to 0 out of round/taper, then the ring gaps will eventually all migrate to the apex of the OOR cylinder area. All ring gaps lined up to lower cyl pressure and suk oil.There is a reason Porsche uses a locating pin on the flat 6 996 piston. The more oor cyl is, the faster the rings all migrate to line up gaps. Ring seating will also be difficult with oor/taper. Hartech, custom made, iirr watching a build in progress I saw these pistons do have a ring locating pin and a strange to me oil ring design. JE CP Mahle jmho

Quotes source post: 20184538

If it were my engine I would at least have them checked.

Quotes source post: 20184538

A little hard to convince aren't you ?? ........I did my best........ c'est la vie.... ....

Quotes source post: 20184700

When a shop uses a honing plate to emulate the cilinderhead bolt stresses in the engine case and then drill/hone to get the best possible roundness of the bore with the cilinder head fitted, wouldn't you then expect to measure out-of-roundness on a bare, i.e. without cilinder head/hone plate, engine case?

Quotes source post: 20185202

yes

Quotes source post: 20185202

I wouldn't expect the OOR/Taper to change much on a correctly sleeved m96. Maybe the biggest change without torque plate would be center bore axis to crank angle center line. Lets put it this way, imo if your new nik'd sleeved cylinders measure out @ .0025" OOR/Taper, with no torque plate, thats not going down to 0 with a torque plate. Most torque plates compensate for the blocks cylinder material head bolt holes thread swelling and puckering/bulging out when clamping force is applied to threads. Thats not how sleeved m96 head bolt holes are set up. On the funky long m96 double threaded head bolts going into the crank carrier, probably not much OOR measurements will change drastically. But anyone that has hands on m96 nik'd alum billet sleeve experience with this please correct me if needed, I could be wrong as my experience is with other sleeved engines/torque plates, other than the re-engineered m96 blocks. So above comments are based on that experience/assumptions. jmo

I appreciate your response. It would indeed be great if M96 rebuild specialists would chime in.

From: Stephen Jacques [[email][email removed]] Sent: Wednesday, August 13, 2025 11:59 PM To: Тикунов Владимир Владимирович < [email removed] > Subject: RE: FW: Tech Info Request - JE 96MC4 Pistons / 96 mm Nickies / M96.03 Sir, Can you please provide a copy of the invoice so I can look up your build? I suspect that you had these parts through Flat 6 Innovations. If that�s the case � you would need to email their ticketing system in order to obtain this information. Stephen Jacques LN Engineering LLC https://www.LNengineering.com 125 Gladiolus St. | Momence, IL 60954 | Phone [phone removed]

In Russian culture, there’s a term — “lokhotron” (basically meaning a scam or rip-off). The engine wasn’t bored out to 3.8. It was simply repaired as a 3.6.

I still haven’t gotten any reply to the invoice I sent — not even to the corporate email. The very same one I said I’d make public.

We have a similar term for that as well. But when you call someone a scam artist on a public forum and don't offer any proof you are the one that looks like the scammer. First you accused Flat6 of doing something 15 years ago that caused your recent engine failure and now 9 pages into this thread you are calling them scammers. People that have no affiliation with LN or Flat6 have offered to help you diagnose the cause of your failure but you have ignored it. You are the one that doesn't really seem to be operating in good faith here, it looks like you've come to the forum with your mind already made up. Stephen's email says to email the Flat 6 ticketing system. But if they aren't responding to you it would be hard to blame them. They did work for you over 15 years ago, you are not interested in diagnosing the failure, and you are going around bad-mouthing them calling them scam artists without offering any credible reason. Half the information you post I don't understand what you are even trying to get at.. do you know that Jake has been doing this for over 2 decades? He has rebuilt hundreds if not more of these engines...

This OP lol. Agree we got word here as well

Okay, that's it. There is no point to this thread. Messing with one of our premiere vendors who has helped and advised countless individuals on this forum is not right. Closing thread.