3,4 engine spun rodbearing!!

Hi, I posted this problem on the noise topic that I had. So if some one knows that is this one of the weakparts of this engine, please chime in. The cyl.5 rodbearing broke completely, and I cant figure why. All the other bearings were like new. No overrevs in ecu memory, nothing unusual. If the services would have been neglegted, there would have been wear on all bearings??? Like I mentioned, the rest of the engine is like new with just litle wear marks here and there. If enyone have good theory, or knows what I must do to prevent this in future, share your thought's

I wonder if a variocam pad became worn enough that pieces of it (or any of the other plastic parts in the engine) got into the oil passageway for that bearing. Was there always sufficient oil in the engine? Perhaps a previous owner let the oil level get too low? With any luck rebuild the bearing carrier, case, and you'll be back on the road. Does it look like there was any other damage? Did the engine seize/other damage or was it still running when you pulled it apart? This is one of the reasons why I think any owner of the M96-01 should regularly change their cam pads... here were mine after 75k. AND there were certainly bits of this pad in the oil sump, perhaps elsewhere? Only a tear down might tell me...

theory says an oil feed passage got plugged.... from what? a piece of silicone, a fleck of metal, a chunk of plastic, an o'ring or any other item thaat may have been floating around in the case from an earlier repair, factory blemish or wear and tear item... just a thought

Thanks, all the oil that goes to the crankcradle, goes thru the oilfilter first. Only thing that is in clean pressure side is the oil cooler, hmm.... Took the crankcradle apart today, and the mainbearing that is on the same oilcircuit with the 5 rod, was allso wery poor condition. So oilcirculation has been compromised at some point of the cars history. I have no service records from the car, so I have no idea what the previous owner has done. All I know is that I'm second owner. Yep, stupid me, never buy a p-car with out recorded history... I think that I chance the oil cooler allso. Found the conrod from england, and local machineshop will repair the crank, if it's repairable.

If I'm not mistaken, the oil filter system in this car is not a 100% inline filter, meaning it only filters a portion of the oil at a time, so over time it will filter all the oil, but not all of the oil must pass through the filter before being distributed to the engine. This design may have aided the possibility that perhaps a passageway became clogged by excess sealant that broke lose or plastic (from wear parts) that did not make it's way to the filter first.

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That just one bearing showed signs of wear pretty much eliminates neglected services or the wrong oil. Without being at the engine to confirm the oil feed to that bearing and other bearings I can only offer the theory that the oil passage to that bearing may have a leak and thus delivered less oil. The oil passages are cast in and when the engine assembled sealant is used to seal the passages. However, a manufacturing defect can have one of these passages leak and of course since it is an internal leak there's no oil on the outside of the engine but pressure and supply are bled away. Also, I'm not sure how to check this but you should try to confirm the oil relief valve that controls oil to the piston jets is working properly. This valve is there to if the oil pressure drops below a certain pressure the oil to the piston jets is cut off to reserve more oil and oil pressure for the main/rod bearings. Sincerely, Macster.

Thanks guys, Logray, I will check that oilsystem. I'm quite sure that all the oil goes to the oilfilter first, then cooler and so on. Macster, the oiljets might be the cause. Will check those before I put the engine backtogether.

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I can't remember where else I read this but here is one source: From http://www.lnengineering.com/oil.html "Most stock engines have a spin on or cartridge style oil filter. In the majority of those cases, it's a bypass filter, where only a small portion of the oil actually goes through the filter . It's the idea that the oil is constantly filtering, so eventually all the oil will get filtered. With full flow filtration, 100% of the oil goes through the filter. This does however require very high quality filters with HIGH burst strengths and durable construction, especially of the internal filtration media, because what's the point of full filtration if the media just bursts and lets the contaminants out and doesn't filter the oil?" Edit: ah yes here it is: http://www.lnengineering.com/spinonfilteradapter.html "The LN Engineering Spin-On Oil filter adapter also helps improve the longevity of your engine by providing full flow filtration, which means 100% of the oil gets filtered without having oil bypass the filter (as the factory filter housing allows for)."

Hey quick question.. is there a way to inspect the variocam pads? pull of the valve covers?

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Yes, you need to pull the valvecovers to check the variocampad's

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The 993 (at least) came with 2 oil filters. The main engine oil filter and a smaller bypass filter intended to trap finer particles that Porsche feared could harm the zero-lash valve adjusters. Over time I guess the concerns Porsche had regarding the zero-lash valve adjusters proved to be unfounded and the 2nd filter was done away with on the new water cooled engines. AFAIK Porsche does not use a pressure bypass at the filter to route unfiltered out around the filter. Any overpressure is dealt with at the oil pump. Sincerely, Macster.

And for the oiljet's. There was couple of jet's where the ballvent was completely open, so I'll bet that there is the reason. Just added those in the parts list... Logray, thanks looking the oilpassages in the block made me thought that all the oil would be filtered. Now I'm sure that I need new cooler, the inside of the cooler is some wiremesh and if the debries got there there is no way to clean it. So, if your variocam pads look like the ones in logray's pics, well mine did. Would it be best to tear down the whole engine???

It also goes to say, because the cam pads and 4th and 5th chains of the M96-01 engine are so inexpensive, if you are going through the effort of pulling the covers off (which requires specialty tools), pulling the camshafts out to replace the pads and chains is not that much more work... of course you need to be comfortable with re-timing the engine (more special tools required). The hardest part of the job is reinstalling the cam covers. The bead of silicone and tightening sequence of the cam cover requires precision and patience. Using too much silicone can create problems with oil passageways becoming blocked. Using too little or not in the right places can mean leaks and you will have to pull the cover off again to reapply. Doing it with the engine installed is not recommended if it is your first time, but it can be done, as I believe speed rII did by dropping his engine a few inches. I do not recommend doing this work without a copy of the work shop manual. Also new micro-encapsulated cam cover bolts should be used if you don't clean and apply Loctite 5900 silicone on the base of the existing cover bolt heads.

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I know the recommendation is there for a blown water pump impeller for a complete tear down. Otherwise blocked cooling passage could lead to cracked aluminum. OF course, I don't know what is worse, a cracked engine or a spun rod bearing. I am not sure about the recommendation for excessively pitted pads or excessive silicone. If so, I need to get my engine back on the stand right away. Of course, it might get torn down anyways due to low compression and worn rings/soot. But I won't know more about that until I've had a time to re-test those things with better tools some time in a few weeks. Not the same noise that you had, but I have a slight ticking on cold startup that goes away after a few seconds, which I believe could be either normal tensioners filling with oil/chain slap, or abnormal oil passageway blockage, or excessive leak down past the rings (or perhaps even valve seals/guides despite valve job) causing slight oil burn off on start-up.

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At the expense you are already undertaking by tearing the engine down, add another oil cooler to your list, it is a very small fraction of your total spend at this point. It's not worth the risk, although I am not certain of the design whether it would allow for such particles to become lodged in and possibly freed at a later time. Still though, for the cost and potential for intermix failure down the road, I would personally replace it.

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While that pad wear looks bad it is not bad at all. The new pads wear in very quickly from the abrasion of the chain side rails until the chain rollers begin to make contact with the pad. Then the wear becomes nil. Essentially the chain rollers roll over the pad. Unless the pad material fails mechanically, suffers a material fatigue failure perhaps, the pads should last forever. My Boxster's passenger side VarioCam actuator was replaced (the actuator failed) but the chain rails which are in constant contact with the chain between the exhaust and intake cams showed very little wear, after nearly 240K miles. If the chain guide/rail sheds any material -- and it can at first -- this material will end up in the oil sump. The material may first go through one oil scavage pump. Once in the sump if they can remain on the floor of the oil sump until well forever. If they are small enough though they can get picked up by the oil flowing into the oil pump pickup and then routed to the high pressure ouil pump, the gears of this will pulverize the material. After leaving the high pressure oil pump these pieces then will be trapped by the oil filter. They may remain in the filter medium or when the engine is shut off the back flow of oil may flush some of the pieces out of the filter back into the filter housing oil. The pieces/material do not circulate through the engine though. Once in the housing they remain there until the housing is removed and the oil with the material in it is dumped out and the old oil filter replaced with a new one. Sincerely, Macster.

I certainly hear and understand your comments Macster. Just thinking outside the box for a little. Perhaps some of it is smoke, who knows for sure... but it is interesting that businesses with solid reputations would make such claims if this pad wear wasn't a problem with the early M96 engine design? And not to mention Porsche eliminating the design from the 3.6L all-together. If not with bits of the pad clogging passageways if they are to live in the sump forever or sucked into the oil pump, then perhaps the pads snapping in two or larger pieces breaking off causing the cam chain to skip or just wear through enough to cause enough cam deviation and timing problem? (of course perhaps these problems could have been caused by improper lubrication in the first place...) In the above pic, what of the bits below the roller that had disintegrated and fell off? Based on your comments, wouldn't the chain rollers prevent any of that type of wear? There are clearly chunks of the pad that have separated from the pad... Last time my oil pan was off, there were many little bits of this variocam pad material in the bottom of the sump, certainly I could have kept them there and probably even added more souvenirs for someone else to find at a future date without any detriment to the engine. What was a little disturbing though was that there were also many many pieces stuck in and probably went through the oil pickup tube screen. Even if they were pulverized or flattened into ever increasingly smaller bits of material, I wonder if enough of these flattened pieces could become stuck somehow in a small oil opening before they ever made their way back into the sump or perhaps oil pump? Some of the oil passageways such as the ones on lifters are very very small. As small as the tip of a ball point pin. I don't believe it would take much silicone material or flattened cam pad material to plug a hole. Then again, with the oil pressure and intense oil flow it is also probably very unlikely to happen, but don't you think the possibility is there? "The LN Engineering Spin-On Oil filter adapter also helps improve the longevity of your engine by providing full flow filtration, which means 100% of the oil gets filtered without having oil bypass the filter (as the factory filter housing allows for) ." - Charles Navarro Without 100% filtration, do you think some of the oil (and bits) bypass the filter and make it's way on to block an oil passageway? "- Replace vario-cam wear pads and the 4th and 5th timing chains at 40K miles if your car is an 01 or earlier 996 or an 02 or earlier Boxster. " http://www.flat6innovations.com/pre-failure-directives If it were made to last forever, why would someone recommend replacing it every 40,000 miles? "Variocam tensioner from a 2.7 with D-chunk failure. Approx. 70,000 miles. All other tensioner guides in this engine were just as delaminated and worn. To solve this issue we are visiting other materials to "shoe" the guides with that can allow for wear resistant coatings to be applied." http://www.flat6innovations.com/engi...es-illustrated If it's design was already "good enough", why would someone look into use other wear resistant coatings or materials to shoe the guides? Again, perhaps I am thinking too far outside the box here.

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I have recently wondered that. Becasue it seems no matter what miles someone said they took their engine apart they say these pads were worn. I wondered about your conclusion and actually came up with the same one on the chain pads.

The rectangular area in red is the area the chain rollers come into contact with. Can you see any pitting or wear in this area? Does that wear look anything like the wear that is presumably caused by the chain link edges on the same surface?

Those wear pads are trashed... But thats the norm for these components, we usually see those from 45K mile engines.

Well, I do not know what businesses claim needs to be done. I honestly don't pay that much attention. The engine will tell you what needs to be done, if anything. The chain guide rails (and this includes their composite plastic coverings) are pretty tough items and designed to avoid wear. I have to add though if a chain tensioner goes bad or starts to go bad this can lead to accelerated wear and tear on the chain guide rails because the chain instead of having constant pressure applied to it instead gets varying pressure and this can result in the chain slapping the chain rails/guides and the rails/guides do not like this. But barring some outright mechanical failure or weakness in a tensioner...The chain constantly runs across this material the whole time the engine is running. If the material were not up to the task, if the design were not up to the task, the things would not last 40K miles. They'd be lucky to last 400 miles. And I can't believe there is that much variation that one car would end up with chain guide/pad material that would last in some cases hundreds of thousands of miles while another otherwise identical car treated in the same fashion would end up with chain guide/pad material that required replacing after just 40K miles. The cost to replace these rails is not insignificant. In the case of my Boxster to get at the actuator guides/rails the labor is 9 hours and the actuator (with new rails) is almost $900. (The rails might be available separately though.) While one is there then if the rails require replacing the solenoid does too and that's another almost $800. My local Porsche dealer charges $150/hour labor so 9 times $150 is $1350. Add in say $1700 worth of actuator/solenoid and that brings the job cost up to $3000 and change. Then in the case of my Boxster new camshaft cover bolts are needed -- the bolts are not supposed to be reused -- and some other hardware, then tax and well, one is looking at $3200 or so. And that's just one bank. Sure an indy might be able to do the work for less money but still that's a large amount of money to spend with no signs of it being necessary. Then there are the chain guides/rails for each of the IMS to exhaust cam chain runs and to get at one I think the transmission has to come of the car. Then there is the crankshaft to IMS chain drive and its rails. Do not forget the tensioners all around. Do all of the above and one is looking at a huge expense. Every 40K miles? I have to point out too that with all of these new parts in the engine the risk of one of the new parts experiencing premature failure is high so there's that increased risk. My 02 Boxster has 245K miles on it. (You just knew I was going to drag this car into the discussion...). Divide that mileage by 40K and that's 6 times I would have had to have the car in for this chain guide/rail servicing. Six Times! Roughly I would have spent $36K on this preventative maintenance since 02. I note I only paid $42K and change for the car new in 02. No way. If any of my Porsches needed this level of preventative maintenance every 40K miles I'd scrap the cars and use the money buy a better designed car. So, I chose not to have it done. But I also am prepared to live with the consequences if I make the wrong decision. But you have to do what you feel is best for you and your car. If this means replacing the chain rails and so on every 40K miles, then that decision is between you and the person you are getting this advice from. Sincerely, Macster.

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Oh, sorry I missed the oil filter thing... I'm not in the business but I don't see that many of these cars sidelined for any reason, let alone something due to inadequate oil filtration. I believe the filtration is adequate. My experience with my cars tends to reinforce my belief. But obviously there are those that believe differently and have different experiences which reinforce their beliefs. I am prepared to live with the consequences of my beliefs. If the engine expires tomorrow due to inadequate filtering of the oil, or using an out of favor oil, or for any number of reasons, well, the next time I might do things differently. Actually, there'd not be a next time because I'd not own another Porsche. I've never had any car I've owned have its engine fail for any reason or even wear out (though I bought a pickup truck with a 'sick' engine that I had to rebuild when I found the ticking was the camshaft bearings missing and the oil pressure nearly non-existent) and I'm not about to put up with that behavior from a Porsche. Sincerely, Macster.

My cam chain wear pads ar 88,K miles

I think that most of us have seen that varicampad's was made on wrong materials. New pad that I changed, were made of completely difrent plastic. I drove with those about 10k miles, and those are still like new. No wear what so ever. My car has 60k miles, so at 50k I changed the pad's that looked just like the prodriver and lograys. For the oilfiltration.What was inside my motor, supports macster's theory. There was lots of metaldebries in the oilfilter, but none in the highpressure side after the filter. Allso allthe oilpassages in cyl.head's were comletely clean. Jake, have you seen before that the oiljets would fail, and leave one mainbearing and conrodbearing with insufficent lubrication?

Man all this talk about the pads and I feel like my car w/ 100k may need some replacements.. Anyone have a write-up on this? what does this pads cost anyway?

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I did my pads at 100k. Here is a pic of the top pad, the bottom had much less wear. The IMS bearing looked new when I replaced it. Car now has 115k+, just finished a 2k trip. Avg 28mpg, car runs great. Secret is to drive theses things alot. No garage queens. Here is a recap replacing the pads and other maintenance items. https://rennlist.com/forums/996-foru...ed-engine.html

Quotes source posts: 8867234, 8867234, 8867234, 8867234, 8867234

The rails are available for about $20 a pair. The solenoid costs about $200. The actuator is around $800. The new cam cover bolts you can buy have a small amount of micro-encapsulated sealant on the base of the bolt head. There is no sealant on the threads themselves. I have successfully re-used existing cam cover bolts by cleaning them, and then applying a small bead of Loctite 5900 to the base of the bolt head. Replacing those rails/pads requires engine diss-assembly. There is at least one documented case of IMS to exhaust cam chain ramp failure, prompting one company to make a billet aluminum replacement. Although this has been the only failure I have read about. http://www.lnengineering.com/chaintensioner.html http://www.lnengineering.com/failedt...ade/index.html DIY assuming one has the expertise just replacing the variocam pads themselves could be done for less than $50 in parts. You would need a small tube of Loctite 5900, 8 new micro-encapsulated scavenge pump bolts, and 2 sets of variocam ramps, you could throw in 46 new cam cover bolts for an addtl $60 or you could just clean the existing ones and apply sealant to the base of the bolt heads to save that expense. This is assuming you already own or have fabricated a camshaft locking tool, which is required before removing the cam covers. And/or a cam timing tool (available for about $200), which has been successfully used to both lock the cams for this procedure and re-time the engine once completed. I'm not disagreeing with you that there are engines out there with 100'ks of miles with the original pads that are probably just fine. In fact, I can't recall seeing many (if any) threads about variocam ramp failure. Are you saying that the older "plastic" that is pitted and worn will have less tendency to fail than new "plastic" which would not be scored or worn?

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Much like the photo 15psi posted above, I can second that. In fact I sourced an old stock actuator and solenoid assembly recently and they came with the older brown material. The new pads I put on about 500 miles ago were also the light colored "plastic". That's good to hear. I'm sorry we've hijacked your thread about a discussion about variocam pads breaking off and causing this mess. Perhaps I shouldn't have mentioned the possibility, since it sounds like everyone agrees it is not possible. I think perhaps my brain linked together too many things (side filtration comment by Charles Navarro and recommendation to change the pads every 40k miles by Flat 6) in order to come up with a wild theory to explain an oil passageway blockage, when I should have just stuck with "blocked oil passageway" as a possibility in the first place. And in the end it might have just been a failed oil jet.

ehhh.. you can only do it by dropping the motor.. maybe ill wait until next year!

The "oiljets" that press into the crankshaft carrier housing spray oil on the underside of the pistons for cooling only & only spray when oil pressure is high enough to get past the check *****. They are not designed to lubricate anything.

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You can actually do the variocam pads with engine in car. You remove the heat shields, mufflers, and lower the engine down a little. Then you can access the cover. I think OP of this thread speedrII did it this way in fact, and I've read about others doing it without removing the engine. It is much easier with the engine removed, of course.

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You are correct, well I think that the jets prowide the lubrication to the cylinders. Couple of my "jet's" was stuck open, so when the engine is hot and oilpressure low, the "leakage" from jet's might be too big, causing the oil starvation on the mainbearing and the rod. My car had the symptoms all the time, I just didn't regognise those. Well, next time (hopefully newer) that these symptoms come back I know that the engine must be diss-asembled. Logray, no problem. I asked opinions of what may have gone wrong, and the plastic from those pad's could cause plockages in the oilsystem. If those got somehow in the small oilpassages

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It may be a possibility then

LINK There are some pics that ihave taken, from various repairs to my car. Secondrow from the bottom, there is 5 pics from lifter change. Same method can be used to change the vario pads... Just wash the engine and enginebay before you start the project. Just calculated the parts cost for the bearing project, and I'm now at 2,7k usd, so bit more that I expected. But not bad at all...

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What are the chances that oil starvation was caused by low oil pressure during hard turns or debris from the engine rebuild. These would seem more likely than the pads crumbling.

15psi, if the oilpressure would have been low becouse hard turns, it would have affected all the bearings. On my engine, only conrod 5 bearing and the mainbearing that delivers the oil to 5 rod was broken. All the other bearings were in good condition, some wear but nothing serius.

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I don't remember if I heard this when I was talking to techs while searching for my car or on forums, but I thought that one main bearing was more likely to fail when you lost oil pressure. The 951 engine has a similar situation that one cylinder is more prone to bearing failure with low/no oil pressure occurrences. I know my oil pressure drops dramatically on very fast turns. And unless you are looking at the oil pressure gage during the turn, instead of the road, you have no idea. I have considered an accusump or a x51 oil return. Do you have a pic of the bearings? And #5 on the crank?

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If you have the engine open and the rail exposed and the rail has an open composite facing and that bothers you then replace the rail with one that has a closed composite facing. Furthermore, I'm sure there are owners out that can do this work with a Swiss Army knife and a roll of duct tape and 15 cents in parts/supplies. I don't care. I do not have any indy shop I'd trust to do this work and I'm not about to use my car as a guinea pig to find one. Also, I do not have the time, the place to do any heavy engine work. Even if I had the time and the place I have no desire to ever open up the engines on my Porsches. Unless it is clear from the engine's behavior that it needs doing I'm not about to have this level of internal engine work done. If the engine does need opening up I'll consider preventative upgrading but only if it needs doing. For instance, when I had the Boxster in for its VarioCam problem I talked to the tech about replacing the actuator chain rails (when the problem was limited to the solenoid) of the exposed actuator and then the rails of the actuator on the other side as well. The tech told me that when we could see the actuator and its rails if the rails were worn and deemed (based on his experience) worn enough to to replace then he'd recommend doing the other side's actuator rails at the same time. The camshaft cover came off and the actuator was exposed and I was informed and stopped in to view the engine innnards. Clearly the rails showed no signs of excessive wear which is what I expected. I would have been more surprised if they needed doing. Now, it happened though the actuator proved to be defective and along with the new actuator it came with new rails. But the wear on the original rails didn't cause the tech to recommend replacing the other side's rails. Anyhow, as soon as I stopped buying fixer upper cars, I haven't had to open up any of the engines in lesser cars I've owned before or while owning Porsches and I'm not about to start with my Porsches. If you or others want to do this sort of work, believe this level of preventative maintenance necessary, then do it and more power to you. In the meantime I'm just going to continue to drive my cars. Took the Turbo to Las Vegas and back over the weekend. Drove the car over 1K miles over 3 days of driving. Left Friday. Took two days to get there. Tired and stopped at Tehachapi for the night. Sunday left LV and drove the whole 530 miles back in one day. There and back all I had to do was stop once in a while for gasoline. That's all the car required. That's the kind of interaction I want with my Porsches. Sincerely, Macster.

How many miles are on the odometer and how often did you change the oil?

If pad wear wasn't an issue the MFR would not have revised the materials that comprise the pads at least 3 times? Its pretty simple.. Every time we pull cam covers on any engine we update the wear pads.. Thats the rule I have made; just like changing water pumps every 3 years no matter the mileage. Over time direct experience and dealing with the same challenges over and over again has taught us exactly what needs to be done and when. Anyone that interfaces with these engines and actually pays attentions and documents every job would see the same things. When the wear pads become worn the 4th and 5th timing chains suffer and so do the vario cam actuators. We have seen engines alter valve timing due to this and the direct result being a loss of fuel economy. I have seen these wear so bad that they were removed in two pieces.. I'll be instructing another "M96 101" Engine Rebuild school tomorrow through Saturday and those wear pads will be put into the hands of my attendees along with a lot of other nice "trophies". If someone hasn't seen these same things we see its pretty clear that they haven't worked with enough M96 powered cars to have a valid opinion~

15psi, rodbearing was on it's bare metal, all of the softer alloys havebeen wear of. Mainbearing was worn to the copper. These ones looked just like mine did. Just some pic that I found on the net. W. DC Porsche, 60k miles on the odo and I have drove about 15 of that. Oilchanges every 5k miles. I have no servicehistory from previos owner, I only know that I'm the second owner of this car. Jake, could you comment the oiljet's? Have you seen those fail? Or am I totally in wrong track on finding the cause?

Sounds like you have a situation where the oil was overheated or where hot oil + G forces created main bearing wear.. The reason the rod bearing failed is because the main bearing failed and contaminated the charge oil to the rod bearing, filling it with foreign object debris and reducing clearance.. The rod bearings are volume and pressure fed (via centrifugal force) with oil by the main bearings, when the main starts to fail the debris kills the rod bearing. We typically see this from the main closest to the flywheel and its corresponding rod bearings. Its common. If you need a crank, we probably have one (magnafluxed, never use an M96 crank without having it magnafluxed!).. I am also developing under and over sized main and rod bearings as well as new crankshafts to solve these issues. I know what causes the issue you have experienced, but stating it on a forum is just dramatic and leads to keyboard warriors and armchair experts shedding light from info they have "parroted" from elsewhere.

Generally instead of something blocking an oil passage causing a spun bearing it's a case of revving when starting the engine. For instance it's cold and you want to make sure the engine doesn't cut out due to extreme cold. Revving the engine at start up even when the engine is already up to temperature is a chance to spin a bearing. Then there's the mistake of having the foot on the pedal when starting the engine and the first thing that happens is the engine revs. Bearings are not the same material as the engine block. They can be spun at initial start up due to being dry and not expanded by being heated up which helps seal things better. But the expanding should be going on after the oil has lubed them up. Another way to spin a bearing is not putting the same bearing back in the same alignment and position in a rebuilt engine when not changing the bearings. And like always there's another oh boy I didn't know that either, when engine oil gets dirty it can leave residue on the bearings that can bake on. High contaminant levels can speed up problems like that. Even parking the car for winter or longer can lead to oil caking dirty stuff on the bearing from oil slowly draining away leaving the dirt on the bearing. Longer healthier runs of the engine help cook out the acidic and other contaminants that run amuck in oil. But if parking a car for winter I'd advise changine the oil before parking and running the engine for a while. There is even ESPEACIALLY after changing the oil do not do anything but idle the engine for 5 minutes allowing the passageways to refill and surfaces to be recoated. Simple life and simple engines. Just the pains are extreme.

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Just curious Jake, doing some research for a possible future rebuild part 2 on my M96-01. Do you offer magnafluxing and balancing service to go with LNE Nickasil 3.4L->3.6L bore and JE pistons (and existing hopefully "good" crankshaft and rods shipped to you)? Do you have a ballpark $ for this? Assuming using a stock flywheel. Thanks

Quotes source post: 8870877

Yes. Magnaflux and our inspection is 175.00 for the crank, whether the crank is good or bad. Dynamic Balancing with our M96 specific fixturing and profiles is 350.00 for intermediate balance tolerance and 375.00 for a race tolerance balance (Intermediate = .5 oz. in., Race = .2 oz. in.)

ok, had some time today and I cleaned up all the engine parts. It's a PITA job, but rebuilding a dirty engine is like shooting ones own leg. I allso looked at the scrachs in the cyl 5, and noticed that they were not scraches at all. The bearing material had gone between piston and bore and sized there... So I did the major no no and used a 400grid wetsanding paper and carefully removed the bearingmaterial from the bores... Before, you can feel the marks with your finger. After, just slight discolouring in the bore. Can't feel marks with finger. I think that this worked out real well, or time will tell if I'm wrong. I will measure the cylinder's next time I work with the engine. I will use this engine anyhow so I will do this just for curious. I will allso take the pistons to be coated, just in case.

Oh, and the bore did not polished at all. I took the last picture after I had cleaned the bore with motoroilled rag..

The sound of this process scares the **** out of me. I will wait eagerly to see how it works for you. I've never had the ***** to try that!

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Holy crap. Wow.

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You can imagine how long it took to make the decision... It took long time to finish this and like I said, time will tell if this was mistake I will have the pistons coated to make the friction on skirts to bore minimum.. But at this point, I had the scraches in the cyl, so I would lose very litle if this method won't work. And If this would be someone elses engine, I would have fixed it some other way.

so, what next? Just discovered that my 1-3 block is new at least not original. Pistons n# 1 to 3 had goetze rings... So the engine has been opened before.

Didn't know you can get aftermarket rings .Wonder if they cost less than 150.00 a hole and hold up ? What rings will you use to reassemble ?

I will use the same rings, just took the rings of becouse I have the pistons coated. Apparently goetze makes rings for 996, the 1-3 cyl rings had "goe" stamped on top side of the top rings. Well, this previous rebuild could be the reason why the bearing fail now.

Thanks .Too bad the rings don't have a part # stamped on them .Last question -I assume you are coating the piston skirts-how did you figure out the piston to cylinder wall clearance ?

Piston to bore clearance should remain allmost the same. The method that my friend uses removes litle material from the skirts before coating so the pistons should keep the same measure. Also the ceramictop reduces the piston expansion. This method is used. Techline

Interesting and thanks for the link .Anxious to hear how this works out .

Part's are here Rebuild will continue tomorrow. Hope to get the car back on the road at Sunday. And for the pistoncoating, talked to my friend that does the coating. He said that the method has been used several times on BMW alusil engines, so I think I'm on the safe water's for that one.

Small progress, engine cases are back to gether. Next the 4-6 pistons.. Putting the pistonpins on these is PITA... Coated piston I allso measured the bores, bottom of the bores had out of round 0,02mm-0,04mm (0,0008in-0,0016in) Top ends had 0.05mm to 0.1mm... (0,0019in-0,0039in)

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Did you buy a wrist pin installation tool or did you make your own? Here's what LNE has to say about out of round and tolerances: "Upon inspection of many high mileage or over-heated engines, the stock engine bores tend to be out of specification, with .002-.006" of ovality, leading to excessive piston clearances, increased ring land and ring wear, and high oil consumption" -from http://www.lnengineering.com/boxster.html Interesting how your top part of cylinder measurement pretty much falls right into the category that they say is common for ovality and specification.

Thanks logray, I had no specs for the measurements just tought that they were on the good side. I made my own tool for the pistonpins.

Based on my research: "anything over .002" ovality is too much. Most of the blocks we get here for re-working have at least that much and upwards of .005-.006". " -Charles Navarro ... from https://rennlist.com/forums/7354638-post21.html We are waiting anxiously to see how this is going to turn out! I hope it works out for you and you get good compression and ring seal. Are you going to measure leakdown and compression after you get it working again?

Well, I had no issues with oilconsumption or fouling a plug becouse of oil. Allso I did dynotest the engine and got 255rwhp, so I don't think that the compression is too low. I dont have the tools for leakdown, but I can measure the compression. Hope to get the engine runninn on Sunday... I will build the 3.7 engine next year, so just trying to get there with this one. Some pics from todays progress. well some of the pics are from yesterday.. Mainbearings Shortblock Sligthly ported intake, allso made some minor porting on exhaust Cyl. head 1-3 in place

Love those engine guts pics.

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+1 Good luck with her Speed.

Thank's guys Here is some more pics. Ported exhaust 4-6 head, yes the chainrails were in wrong positions... This is what you get when assembling engine when you are tired.... well easy fix, and noticed it before I put the head on... Cyl. head Again.. Progress Allmost done Engine with exhaust and gearbox 310kg, the forkliftpallet was 20kg Drove the car home tonight, spend 14h on the garage... Works like a champ, allmost, I have mystically lost my idle. Or it idles allright, but only 600rpm. And if I "plip" the throtle engine will stall becouse rpm's drop below idle...

Very cool..... I may be bothering you in the future for some help as I rebuild my Vortech supercharged 3.4L later this year. It looks like your quite the 996 engine PRO now Whats your oil pressure like? I hope you get the idle problem taken care of.

Wow, amazing you got it together so fast. Check the crank position sensor, perhaps that is the cause of the low idle. Or if it is idling rough it could be an intake leak. Great job though getting it back together so fast!!!

Herman, I have allso been thinking a supercharger, do you like your's? How many miles did you drive it before it need's the rebuild? Logray, Ill take a look today. The idle is smooth and solid 600rpm, no "idle up" on the cold start. I will check the IAV today, I think that it's the cause.

Thanks for the update and sharing the project progress along the way .Just out of curiousity how many kilos/miles on the car ? A few of the methods might seem unorthodox but appear to work . Dave

Ok, problem solved. The idle air valve was stuck, cleaned it and it work's again. Took the car to 120km side road spin... priceless dcdrechsel, 97k km on the car. Allso noticed that it wont take too much g-force to drop the oilpresure. I was driving those nice twisting roads about 100km/h and noticed that on tight corners oilpressure will drop from 4bar to 3bar fast. Right turns were the worst, I got the oilpressure drop to 2,5bar. I will make new bafles to oil pan (as soon I have the time), hope that it helps.

Thanks Speed for the write up on your engine. Glad the idle fix was so easy. That road in your last pic looks wonderful, glad to hear all is well with your rebuild.

This thread has a happy ending! The startup noise is gone, and the car seems to have good power?

Well, just tryed the car. The startup noise is still there.... But the car feels good on power, and the noise must come from someother part than engine. I suspect the starter motor, I rotated the bendixwheel when the starter was in my hand. It was very stiff to rotate... Anyways, now that the engine can be ruled out, I not too worried about the noise.

I like your process of elimination. Engine, check. Must be the starter motor.

The 'ported exhaust' looks a little rough. Did you go in there with a grinder and just take out some metal? Flowbench?

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I think I'm on the "no polishing" side at the portings. Did not use flowbench, becouse only litle material was removed. Exhaust ports are very narrow where the two channels combine. I took some material out from the divider, so the ports open up smooth. Might lost some low end flow, but will gain more flow on the topend. Don't think that the porting will affect now with stock exhaust, but after the 200cell cat's and new exmanifold there should be some gain.

Hi there Neigbor, Just out of curiosity, did you perform compression and/or leak down test before and after? Regards, Johan

No, I did not perform any compression tests before or after. I have now drove the car about 200miles, and no problems regarding to the oil consumption or power. I'll measure the compression after next oilchange, I'll post the results here.