Second early-build 996, same oil pressure drop in corners

For those who were wondering/asking for follow up on this: I have now have two early-build "amber" 996s. A coupe and a cab. Very similar build specs. Cab has 100k miles and Coupe has 76k miles. I have a long thread on the Cab where I was trying to resolve big sways in oil pressure going into turns. Dropping from 4 to 1.5 and the needle just floating around while going through canyon roads. [ https://rennlist.com/forums/996-foru...e-ticking.html ] Mechanic hooked up an analog pressure gauge and confirmed the pressure does drop. The coupe is new to me and finally got a chance to push it on the same canyon roads (as far as safe as need new suspension). Oddly enough, this one registers a hefty 4.5 after fully warm even at low RPMs (not including idle). And then into tight turns, the pressure drops almost the same delta at cab down to about 2-3. The coupe doesn't show any telltale signs of a bad sender: it reads zero at ignition on, pressure rises from idle (around 1) up and down smoothly, but the fact it reads high 4.5 at most RPMs, maybe it's bad. Only difference is it runs higher under normal driving than the coupe. The cab at very hot temps still has the issue where it dips to .5, check oil light and the engine tick at idle. Tick is almost 99% lifter noise due to low pressure. Coupe, I wasn't able to get the engine hot enough, but definitely no signs of low pressure at idle. So there it is, same engine, same oil pressure drops in turns. The only major difference is the Coupe's oil is filled to max where cab is at 1/2. But I don't think higher oil levels affect any of the above (pretty sure i tested the coupe last summer by filling it to max). Coupe will be getting UAOS installed soon, and can overfill to test. But maybe the pressure drop in turns is just the nature of the amber-build engines....???

I was under the impression that oil pressure drops in turns were just a fact of life with the M96 engines, hence all the products that aim to mitigate them (UAOS, deeper pans, baffles, etc.). In either engine, have you updated the oil pressure relief piston and spring to the 997 part? It's a pretty cheap part and easy to replace.

Quotes source post: 19832042

That is quite possible, and probably the final answer to the issue, but there are others who have no issues, and some who had issue and things like relief pistons, or miss-oriented scavenger pump plates, fixed it. Yes have done the 997 piston and new spring.

Oil pressure drops in the M96/m97 are a fact of life during higher G turns. I suspect it's the same for the 991 & 992 as well. But oil starvation/pressure drops can be mitigated with the right bolt on equipment. Ben, contrary to your point, the way that you mitigate oil pressure drops is to get more oil in the engine above 8.5 qts full. But the only way you can safely add more oil above full, is to have an AOS that can effectively process more oil and drain it back into the sump. The OEM AOS cannot, the Porsche Motorsports AOS cannot, but the UAOS Track can. Further, the UAOS Track will allow you to run 1-2 quarts more oil over full. In addition, by bolting on a 2 qt deep sump, you can get even more oil in the engine. Don't waste your money on a 0.5 qt sump. Not enough oil. You gotta go big with a 2 quart or go to an industrial strength solution which is the UIDs. As an example, using a 2 qt deep sump and the UAOS Track, I am able to run 4 qts of extra oil above full which is 12 qts of oil in my engine. In reality, its about 12.5 because after an oil change there is ~0.5 qts still sitting in the engine. Every time i change the oil, i put in 12 qts. Much better than 8.5 which is what most are running. Easy as he'll to do.

Oil pressure drops in ALL M96 cars are well documented on this forum. I have a 996.2 and observed pressure drops during �spirited� driving on the street with street tires. I�ve since installed the LN 2Qt deep sump, which has eliminated my observed pressure drops on the street. I�m still running the factory AOS which has tested within spec by manometer.

Somewhere there was a thread on this. In the thread someone posted pictures of the cylinder head castings of the 3.4, 3.6 and 3.8 M96/M97 engines. There is quite a bit of empty space inside the head where oil from the sump can go and hide during cornering. The 3.4 was the worst of the lot. I remember thinking that there was room for at least 4-5 quarts of oil up in the head. The oil can get up there by being pumped through the oil system, or by migrating through the timing chain area. The left head has the timing chain moving in a direction that would drag the oil into the head and Porsche provided a deflector to minimize this, though I have my doubts about how useful the deflector might be. This suggests that a larger volume of oil could possibly help. If 5 quarts of oil runs away and hides the the left cylinder head having extra oil in the sump could be beneficial. Getting the oil back to the sump is also important and supposedly the 997 oil return pipes are better than the 996 swirl pots to do this. The scavenge pumps are an important piece too. I remember you checked these on your Cab, check them on this car yet? At some point there is only so much that you can do.

Yep. Comes down to whether any 996, 986, 997, 987 owner wants to help mitigate the risk of oil starvation and oil pressure instability with a couple of bolt on parts or they don't. All we can do is discuss the solutions that are available. The owner has to make their own decisions if they want to spend the money or not.

I was just documenting the correlation between the two cars. Some others had posted on related threads asking if I had seen the same with the new coupe. And since we have a 150 page discussion on the cabiot's problem, and a lot of "try this", "try that" to fix the inherent issue, I'm not looking for a solution per say here. Have a UAOS with track drain being installed. Looking at sump options. All is good!

Get yourself a UIDS!! Stress-free driving - I don�t look at my oil pressure during turns anymore. I also recommend you skip an extended sump. Ground clearance is important due to the imperfect roads in the canyons.

No question, the UIDS is the best solution coupled with the UAOS Track.

Engine version, or head version is one variable we didn�t get to explore in the oil pressure thread. I�m pretty sure that�s where the pictures of the heads are. @Ben8jam, if you are looking for an extra challenge, you can instrument your car and collect data as you take the engine through this process. I�m happy to add new variants to that data set. and thanks for sharing your observations about the second early engine. I would guess this is the behavior that started the 1/2qt low and longer dipstick changes.

Quotes source post: 19834482

100%. While there are other ways to solve this issue (such as an engine from FSI), none are as elegant and simple that also actually re-engineer the limitations of the original design for an existing healthy engine.

Quotes source post: 19834661

I do remember threads on this, with those pics. IIRC, the big differences are: volume of oil that these heads can store, channel/pathway where oil cannot flow down as easily due to gravity, pockets/pools of oil from g-force that gets held up in certain areas of the heads (and therefore can�t be scavenged). Porsche also added a 3rd scavenge pump on certain engines (X51 I think?) to help mitigate the issue. But the big difference between 1999 and 2025 has to do with tire technology pushing G-force way up. Couple that with engine wear (which equals more oil volume pumped from the oil pan), and we now have oil starvation that is now pretty common for these particular engines, even in the street.

For sure. Unless it's a race car properly set up from the factory, it's gotta be solved for. Last February, I was at the Chicago car show enjoying a conversation with a bunch of new model Corvette owners who were complaining about oil starvation and engine failures at the track. They didn't realize they had to take preventative measures for oil starvation. Go figure. Sounded like a PCA meeting.

Quotes source post: 19840574

My FSI 3.8 stage II still had op drops on hard right hand turns. UIDS was the only mitigating factor. YMMV BTW� the UIDS does hang lower than a stock pan. I�m not sure of how it compares to other �deep sumps� dimension wise, but it is pretty low (not a lot of clearance).

Quotes source post: 19834159

Spot on. Race oil is a must in these engines on track. I will just add that for sustained oil temps of 225F and higher or intermittent above 240F, it's better to run Driven XP6. This is what Jake has always recommended for his engines when they see track use (or any driving where you wear a helmet). We have several Boxster/Cayman oil cooler solutions that address the high temps that make this problem worse, but packaging makes putting one on a 996/997 is more difficult. We have a kit fully developed, but it requires running muffler deletes or a GT3 center exit muffler setup, however there haven't been any takers.

Quotes source post: 19841723

The UIDS has .400" more ground clearance than 2qt deep sumps, and is .600" deeper than stock sump ...

Quotes source post: 19832268

How close does that extra 2qts get to the crankshaft? With the BMW's we overfill them until the windage tray is basically still wet with the engine running. Anything less than that and long left-handers are basically asking for it. I'm curious how much oil you can push into the M96 if you had all the head scavenging in the world to put oil back in the sump. Something like the E60 M5's pair of electric scavengers for instance: Push the sucked up oil into the UOAS Track or some other air separator, dump back into the X51 cage or something so it can't escape the pickup immediately. Viable? Harebrained?

The M96 has an "Integrated Dry Sump" that is unique and doesn't require the windage trays like wet sumps do to keep the oil from splashing from the crankshaft....The crankshaft is housed seperatly from the Sump with just two "widows" that use gravity force to get the oil down from the crankshaft to the Sump, but the oil in the IMS area and chain area, and heads on a "flat 6 engine" needs pumps to pump this oil back to the Sump...The Mezgers use dual scavenge pumps on each head that pull oil from front and back,, the M96 uses two single stage pumps that one pulls from the front of one head and the other pulls from the rear on the other head.... There is a early X51 3.4 ( not available in the US) that had a dual pump on bank 2.. There could be extra electric pumps added to the M96 but it would not be very elegant.... Overfilling the " Integrated Dry Sump" does not effect windage/horsepower or aeration on the M96 like it does wet Sumps... but in high G corners when the oil pools in one head the timing chain will sling the oil right at the AOS port and overwhelm it, the UAOS has a feature that prevents this and is 4x more efficient at keeping the oil out and allowing the extra oil to be ran with no issues...

Quotes source post: 19846125

If it really were a dry-sump tank effectively bolted to the bottom of the engine, we could fill it up to the hilt and oil starvation would be a solved problem so long as we had enough scavenging (and UAOS not choking) to keep the tank full enough. But that's not the case, right? We unfortunately don't have a one-way valve from the crankshaft area to the tank. The gravity drain holes allow sufficient lateral G's to push oil up out of the "IDS" and end up in the heads, which effectively reduces the height of the oil column available above the pickup. So my question is what stops us from filling this cavity all the way up - if even the UAOS would get overwhelmed, then I think the logical answer to is add inelegant auxiliary scavenging to the heads to force as much oil back down as possible. If UAOS can handle it, why not run 12+ qts of oil on the stock sump plate? Etc. Run the oil level literally higher than the confines of the "IDS" up until the crankshaft licks it (I believe that's a hard limit, no block design or windage tray is saving you from aeration at that point, correct me if I'm wrong).

The crankshaft area is sealed form the heads ..so oil from the crankshaft does not end up in the heads but the oil in the crankshaft area in high G turns cannot use the gravity to drain down and hides in cavities within the crankshaft area....(there is enough area that is just unused space to hold a couple of quarts oil) The problem with the "Integrated Dry Sump" that is unlike regular dry sumps, is that the M96/7 Sump is flat and 14 inches wide and only 7 inches long..,.This 14 inches wide and flat Sump allows a large volume of oil to shift to one side in a 45 degree angle under 1 G of cornering......That's where the Twin Tunnel Port /UIDS shines....It has ports on each end of the 14 inches that switch sides as needed to allways be in the deepest best, less aerated oil when cornering at any g force.. Traditional dry sumps use a" remote mounted" external tank that is tall and circular and tapered at the bottom and is not much effected by cornering high G forces ....but the tank on the M96 is wide short and flat on the bottom of the engine integrated into the design..

Thanks for the explanation Skip. Because the UAOS Track can more effectively process the oil versus the oem AOS and motorsports AOS, i am able to run ~12.5 quarts of oil in my 3.6 rather than 8.5 quarts. 2 of those extra quarts comes from a deep sump and 2 more quarts comes from the UAOS Track. So when I change my oil, I fill it up with 12 quarts plus whatever is still in the engine that didnt drain. No smoke and no issues on the track nor street. Just more oil in the M96 which keeps it happy.

Does everybody believe the mountain of data and results of the oil instability thread...?

Quotes source post: 19846366

Did someone say data? That's a cool thread. A lot of twists and turns, but the data shows pretty clearly what 'we' need to do to protect these engines. We should argue about the dividing line. When does someone need all the mitigation? 0.7G, 0.85G, 1.05G? And what oil temp? And we can always use more data for that thread. Fill in the blanks!

Quotes source post: 19846410

The M96/7 has 58 oil leaks paths/ flow paths ....6 rod bearings, 7 main bearings, 16 cam bearings, 24 lifters , 3 chain tensioners, 2 vario-cam actuators ... The lower end has a total of 13 leak paths/ flow paths where ~ 60 % of the flow goes The top end has 45 leak paths / flow paths where 40% of the flow goes Any minute wear will increase the flow out of the sump to these 58 leak/flow paths....Just a 1 thousands wear can increase the flow dramatically, and an increase in oil temperature will increase the flow out of the Sump dramatically also.... Normal flow on a healthy engine is ~.5 quarts per second at 4k RPM and 90C oil temp. That's why I always recommend using 50 weight oil year round ( unless your in sub-zero temps) and use all the mitigation you can afford ...Like the UAOS/UIDS... because 99% of the owners can't know what the internal clearances are unless the engine was blue-printed with mostly new parts and all specs given to them...Most owners are not the original owners since new ....

Quotes source posts: 19846248, 19846248

Sounds like this is the real problem area of the engine that needs scavenging. But yes, a million times this. Most dry sump tanks are almost conical at the bottom so there's always oil on the pickup until you have the car on its literal side. Without trapdoors on the gravity drains, or UIDS, or straight up blocking off the gravity drains and using scavengers to move oil from crankcase to IDS (wouldn't that make it a true IDS?), the IDS "tank" really just behaves like an LS wet sump.

Assuming you have a robust IMSB and your engine is in fine shape, there are 4 main catastrophic failure points on the M96/M97 that are easy to solve for today as it relates to tracking your car. 1. AOS failure & hydrolock 2. Oil pressure instability & starvation 3. Water pump failure 4. Water & oil cooling Here are your readily available solutions 1. AOS - run the UAOS Track with 1-2 quarts more oil above full. 2. Oil - run the UIDS for an industrial strength solution, or a 2 qt deep sump for a commercial strength solution. You can even add an accusump to either configuration as a "just in case" set of belt and suspenders if you like. 3. Water Pump - Keep your water pump fresh so you dont run the risk of the fins breaking off and lodging in the heads causing heat cracks. 4a. Water cooling - run low temp thermostat and add 3rd radiator. 4b. Oil cooling - add LN Cayman oil cooler kit for industrial strength, or the 997S oil cooler which is bigger than the 996 cooler but not as robust as the LN Cayman cooler. For sure, there are plenty of variations of the above solutions that you can use depending on what you want. But we have viable solutions today versus just a few years ago. IMPORTANTLY, the UAOS Track, UIDS and LN Cayman Oil Cooler Kit did NOT exist 4 years ago. They are all new solutions. Good to see! Don't forget to run great high viscosity oil that can handle the heat of the track and keep it fresh.

Quotes source post: 19846504

Here is a picture of the crankcase half on the M96. The red arrows and red rectangles indicate area's where oil can hid in the crankcase during high G corners and the yellow rectangle ( or window) is where the crankcase oil gravity drains to the Sump.....This area cannot be scavenged and cannot be modified unless during a rebuid... That would be an engine builders job not a bot-on.... The things I designed ( UAOS/UIDS) were to be used on existing engines of various health and on new engines as well... The area in blue are where oil can hide in the IMS area and also shift from one head to the other on high G cornering , it is sealed off from the red/crankshaft areas... The Integrated Dry Sump differs from a LS wet Sump in that in a Wet Sump the crankshaft Whip up the oil in the sump and loose horsepower and also aerate the oil extremely. This is why overfilling a Wet Sump is ill advised... But in the Interagted Dry Sump the crankshaft is well away from the oil level and well sealed off from it so the limitations of overfilling are mainly restricted by the efficiency of the AOS ventilation system.. The UAOS solves this problem....And the Integrated Dry Sump does not allow the crankshaft to whip the oil to loose horsepower or to aerate the oil... I have spent the last 4-5 years of my life studying theses issues ..to developed the UAOS/UIDS and have thought on numerous different ideas that just were not practice of would package well plus the subject matter is highly dynamic and involves a good bit of physics/quantum physics to understand fully...

Do you think the UIDS would react quick enough to not even have a hiccup in head pressure oil column In this Schrick dyno test rig..? I've read the 997.1 failed this test badly with a thrown rod.... Would UIDS prevent this on an extended test..? IIRR, 997.2 passed test with 4 scavenge pumps in sump and total of 7 oil pumps if I counted right,,, and its IDS. Ya Porsche knew the m96 had a defective lubrication system, in need of a re-engineered set up. You Tube

Quotes source posts: 19847807, 19847807, 19847854

True, and I'm not saying your work doesn't help a ton. But structural limitations of the M96 can/should be solved at rebuild time if we can identify real root-cause ways of doing it. I don't think we're on the same page for how idiotically high I'm proposing to fill the M96's crankcase to. Let's say, 20 quarts - the oil is at least getting close to the crank at this point. But assuming UAOS can handle that level of overfill, the pickup will be submerged for sure, we're almost using the crankcase walls as the IDS tank. What's stopping us? That's a badass rig and exactly the kind of test this stuff needs. UIDS is already orders of magnitude better than stock (low pickups + two of them, one will almost always be submerged) even if people still see split-second dips as the ***** switch ports, considering many of us see oil pressure drops even below 1G on stock oiling. But this also highlights my assertion that scavenging is really important - there are wet sump engines out there that will handle the Nordschleife without starving without even a pan baffle. The more we can scavenge and submerge the pickups (the closer we get to a real dry sump, lol) the more we help the system as a whole.

Quotes source post: 19847854

I think it will do fine. The only time I see a dip in oil pressure (from +5 bar to 3-4 bar on the 997 oil pressure gauge) on my car while on track is when braking above +1g. It would then recover within a second or so after that. The inventor can explain the reason for that. I am still on stock AOS and running around 9-10 qt of oil.

Quotes source posts: 19847854, 19847903

That rig cost upward of $1mil and was designed specifically due to the inadequacies of the M96/7 in high G corners..... It even says so in the Owners Manual.... At the time of the M96/7 Porsche still had the top of the line GT3 that could have handled this test rig...so the M96/7 was built to a price point to deliver a lesser car that had "most" of the same DNA ... Yes, with all the testing I have done I'm sure the UAOS/UIDS + 12 qts of 50 weight race oil would do marvelously on this test rig... I have built simulation rigs to test the UIDS, and have tested on the Track at extreme low oil levels and extreme high oil temps ( above 300F) just to see the efficiency and tune the baffles. I even considered to strap the car to a steel platform and have a Crane pick up one side of the platform to verticle angle , then do the same to a GT3 to show the performance of the UIDS, just never had the time... Additional Scavenging can only really be done on the heads, Yes it has already been tested with dual scavenge pumps on each head by Jake Raby and he says the results were not impressive ....LN may still have a couple of those pumps , the obviously can help slightly , but if no one buys them they will be discontinued.. Yes I think that test rig is awesome, I would love to get some time on that with the UIDS to show everyone the performance.. .. If you have or come up with any concepts you want to explore, feel free to run it by me first before you spend a lot of time on it because I can assure you I have thought about it and thought it through to an end....

UAOS & Sumps UAOS Track https://ultimateaos.com/ UIDS https://ultimateids.com/ols/products/uids-911 LN 2Qt Deep Sump https://lnengineering.com/2qt-deep-sump-oil-pan-kit-inc-pickup-tube-extension-windage-tray-x51-baffle.html

LN Oil Scavenge Pumps, Oil Cooling & Water Pump Bank One https://lnengineering.com/products/b...mp-bank-1.html Bank Two https://lnengineering.com/products/b...mp-bank-2.html Oil Cooler Kit https://lnengineering.com/products/o...&mode=list&p=1 3.8 Oil Cooler Said to be a direct fit for 996 https://lnengineering.com/05-08-porsche-911-3-8-engine-oil-cooler-99710702502.html LN Water Pump Kit https://lnengineering.com/porsche-oem-986-996-water-pump-kit-inc-gaskets-serpentine-drive-belt-bolts-160f-low-temp-thermostat-driven-csp.html

The above referenced items should help for those that are trying to figure out the path they want to take. I am sure that I have missed a few solutions from vendors that should be posted. Hopefully they do. The more the better.

As an aside, I find it interesting that the same basic physics problems that affect last century engine design and performance (thermodynamics, fluid dynamics) are equally relevant as to what NVidia solves with modern AI systems here in 2025. I�ve been reading up on the 2025 NVidia announcements, and while there�s a ton of software, networking and hardware tech, to make it all work correctly, they spend a lot of time designing airflow, fans, power, etc. It�s actually critical to achieving the next steps in performance and reliability. Goes to show the rubber always meets the road somewhere, and that bit is still super important.

Quotes source post: 19846451

IMHO, you missed a leak area. The crank carrier 'oil gallery' thats hardly a real oil gallery. More like a channel cut into crank carrier halves that must mate/seal together perfectly under high oil pressure with no sealer or gasket.... Ya, agree that dyno test rig is an amazing piece of machinery. Didn't realize its a million dollar baby... Wonder how all the currently available 996 engine swaps would do on Schrick dyno test rig..? Agree 100% that your sump is the best piece to help correct for a defective engine architecture/design... IMO its really to good of a piece for a m96.

Quotes source post: 19848092

Which makes sense due to what you say, the crankcase not really being in the same drain path as the heads as it would be on a "normal" inline or V engine. That sucks, fundamentally I think we agree the crankcase is the problem, but there's no obvious path for a bolt-on solution. In dry sumps we don't fill the tank all the way up because the AOS system is literally the top 1/3 of the tank; the breather is typically at the top as well so filling up all the way leads to oil being pissed out of the tank (if the breather goes to the intake like some OEMs have it, that's catastrophic). If you offload the AOS action, and breather action, to a separate component you don't actually need an air gap in the tank, any mostly vertical tank is fine as it is really just for storage at that point. But that's what the UAOS does if I understand correctly - handling the AOS, any air pressure relief, and trickling unaerated oil back to the sump - acting as the top 1/3 of the dry-sump tank. Unless there's something in the crankcase that also shares this responsibility, it sounds like reducing the free air space in the crankcase shouldn't be an issue up until the oil level is high enough to get whipped by the crank. Sigh the cost of testing this on an M96 is 20x worse than a pedestrian K24. Thanks for answering my questions Skip, I don't have any more to contribute until/unless someone gets a real look inside the crankcase with the engine warm and undergoing lateral/longitudinal G transitions. Wish I still had access to my old aerospace work, there's lenses and light probes like this that could be used to get a good look inside the engine: https://rvasynergies.co.uk/industria...doscope-lenses

Quotes source posts: 19848829, 19849405

One simple thing that could be done during a rebuild that would be quick easy and would help a lot would to drill the oil return holes in the IMS case area ( circled in Purple below) .. there are 4 of them which or 6mm, it would be easy to drill then to 10mm and increase the drain back 4x...This should really be done to ANY m96 during a rebuild and can be done in 10 min at no cost .......I don't know if any of the M96 rebuilders are dojng this,. may be some here who have had engines rebuild can check next time they have the Sump off....because it really should be done and is a no-brainer...

Quotes source post: 19851454

Skip, great info on the oil return holes. During a rebuild, are there any other internal approvements you would make?

Quotes source post: 19851789

That's a big question that I feel almost needs a Novel to be correctly answered, but I'll try to condense it to a few paragraphs so it won't be too boring...It will probably leave out more than is included but maybe will answer the question.. Back in the 80's when I developed my World Record holding 2.0 liter T-88 Series SOHC engine ( same bottom end/ block as the Cosworth YB but was SOHC instead of DOHC ) ..That went from 96HP to 525HP in 7 years ...Started as a production SOHC engine at 96HP, then to 125hp then to `175hp then to 325hp then to 425hp then to 525hp from 6K rpm to 12k rpm in 7 years still using the stock block, head, crankshaft, and timing gears... all else was designed by me to specs.. I scrutinized every nut , bolt, passage ,clearance, and modified every system, like oiling, cooling and air flow./exhaust flow...to get dependability at 2x the RPM at 5x the HP.... Like all engines the M96 is (~400lbs) of Aluminum and Steel and nuts and bolts, all molded into shapes and bolted together using manufacturing techniques and Engineering into a final product....all of which could be modified/redesigned if found necessary to achieve ones goals .. Beside the internal upgrades that are already available and common knowledge like improved cylinder bores, IMSB , these are the few simple things I would do in a "normal" rebuild... Blue-Print all the engine clearances making sure all 45 of the top end clearances/leak points are at the minimum ( tightest allowed) to keep from flooding the top end with oil when the oil temps get really high ......... Blue-Print the bottom end clearances so that they are NOT too tight and allow good oil flow for cooling Balance the rotating assembly to within .5 grams.. Drill the 6mm IMS drain holes to 10mm+ Use high quality 50 weight oil year round ( unless sub-zero temps) Install wire screens on the Scavenge pumps inlets ( there has been many many chain re-action catastrophic failures from just a small piece of debris getting in the scavenge pump that locks up the pump, which will break the timing chain, which will cause the valves to hit the pistons, which can bust the pistons and/or cylinder walls, and put holes in the block) If you plan on a lot of continuous high RPM usage like many many Track Days, I would definitely spring for upgraded 4340 Rods during a rebuild.... That's about the extent of internal mods I can think of on short notice, I wasn't really prepared for an in depth answer so may have left out something.. All other upgrades are "bolt-on" solutions that I would recommend to all M96 that are very very highly effective at making it robust and bullet proof...( like UAOS/UIDS .....sorry I had to pat myself on the back at least once )

Quotes source post: 19852748

Thanks Skip. Time for you to write a book!

Quotes source post: 19852766

LMAooo .. I doubt it would reach the NYT Best Seller List ...

Quotes source posts: 19846410, 19840574, 19847903, 19848829, 19849405

Wow. Great thread. I'll start with how we solve the oil instability issue before I begin responding to individual posts. We are the only M9X engine rebuilder that I know with a 2 year warranty that covers track use. The caveat is that our customers have to use the oil and oil change intervals we recommend, submit to us their on track temp and oil pressure data, as well as a used oil analysis at every oil change. Based on this constant stream of data, we've been able to verify that our engines are staying healthy for both track and aggressive street use and course correct the ones that were "at risk". Slakker track engine requirements: Oil - Motul 300V 10W60 or Amsoil Dominator SAE60 Oil Fill Level - Between Max Fill Line and 1.5 qts overfilled Center Radiator Hartech Racing Sump (We also support UIDS or the FVD .5qt for AutoX and an occasional track day) 997 oil return tubes (99710701600) In addition, we recommend the following: Motorsport AOS or UAOS with drain back Oil temp, pressure, and RPM data logging These were developed based on the work done in the Oil Instability thread and then refined to cover the broad array of experience levels of our drivers The Oil Instability sh*t show (I'm just as guilty as anyone) should be left dormant or closed in my opinion. Now a new thread on the other hand that picked up where it left off could be of real value. And I have alot of data across multiple M9X cars and driving styles that I could send you.... 1g, which puts the oil at 45 degree angle, is easily achievable on performance street tires and we've seen drops both on street and track use. Do you have any details you can use to expand on this statement as it is inconsistent with both my personal experience years ago and what I've heard from others anecdotally. Not required. I was out in California a few month ago supporting a 4.1L M97.21 endurance racing engine we built with a Motec M150 ecu. We installed a dipstick during the rebuild and started with the oil level 1/2 way between min and max after sitting overnight. Similar to Jason's original testing, they went and did a 15 min session, came back in, we reviewed the oil pressure data, added 1/2 qt, and repeated. After adding 2 quarts (1.5 quarts past max fill line), the pressure stabilized. This was with a pro driver on Hankook RS4's. So how much oil is getting trapped in the heads on track? At least 1.5 quarts. There were still some minor drops but the team couldn't get 300v in a 60W as Motul was transitioning from 20W60 to 10W60, so they had 15W50. Baz can be a little abrupt and defensive initially but that doesn't mean he's not listening and won't ruminate over it later. Your comment may very well of led to their use of sealant between the oil galleys and the crank carrier as that was their process by the time we partnered with them which was after Baz's ban on RL. That looks frickin awesome. Any idea how much it costs?

Quotes source post: 19854349

I'd remind you that it was the embrace of likely tension that eventually ensued in the community that allowed that thread to be of any value. Before that, the only advice given to this problem was complete bull**** and likely ate a lot of engines. If I just got along to get along, mine likely would have been one of them. Additionally, the information that came out of that thread has allowed people an opportunity to monetize solutions to a problem that was long thought by the masses to have already been solved. Including solutions around rebuilding to mitigate inherent M96 oil supply shortfalls. You're welcome. I like you for the most part, but I don't give a **** about your opinion on my thread. ETA... Glad you have collected "lots of data" - you should send to Paul to format and post, he has a knack for making it digestible to the masses. Now THAT would be valuable to the community.

Quotes source post: 19852748

I'm only going to comment on the internal suggestions as I think the external ones have been well hashed. 1. Blue-Print all the engine clearances making sure all 45 of the top end clearances/leak points are at the minimum (tightest allowed) to keep from flooding the top end with oil when the oil temps get really high ......... - This is the only one I strongly disagree with. Running on the tight side significantly increases the chances of wearing or spinning a bearing with negligible impact on "system" oil pressure over running on the looser side of the spec, where we prefer to be. Adding a direct oil feed to the IMS has a greater impact than bearing clearance and it's a psi or two max. 2. Blue-Print the bottom end clearances so that they are NOT too tight and allow good oil flow for cooling - I don't have an issue with this one. But since our Hartech cylinders and pistons come as matching set contract manufactured by Capricorn(manufacturer of F1 pistons!) and honed within +/- .1 thou of Hartech's spec every time, something near impossible to achievable with "off the shelf" piston sets, it isn't a clearance we would alter. 3. Drill the 6mm IMS drain holes to 10mm+ - This is pretty brilliant. Are there any downsides or risk, besides structural integrity, to opening them up further or adding additional holes? 5. Install wire screens on the Scavenge pumps inlets ( there has been many many chain re-action catastrophic failures from just a small piece of debris getting in the scavenge pump that locks up the pump, which will break the timing chain, which will cause the valves to hit the pistons, which can bust the pistons and/or cylinder walls, and put holes in the block) - IIRC the dual scavenge pump on the 9X7 has this but I haven't seen it on the normal scavenge pumps. 6. If you plan on a lot of continuous high RPM usage like many many Track Days, I would definitely spring for upgraded 4340 Rods during a rebuild.... - Agreed. While the stock rods are pretty decent, about half the sets we test have at least one with 10 thou or more of bend or twist. So we recommend Pauter rods on all of our builds but they are an option, not a requirement, since we do our own machining and can replace/hone the small end bearings and match weights within a gram. Interestingly, Porsche spec is that they are within 9 grams of each other. While we would never build to that spec, I think it lends itself to the fact that there is not as much to gain by balancing opposing 6 cylinders since the weight differences don't compound exponentially with RPM like they do in a V design. One other modification I've been thinking about is what if we filled in everything below the blue line with epoxy, following a similar slant to the one the picture is taken at?

Quotes source post: 19854372

Oh Jason, you are always so dramatic. I didn't say archive it. And are you forgetting that I sent a significant amount of data to Paul for posting in that thread? Or did you miss that I give it credit in the post you are responding to for helping come up with the basis of our guidelines? There are about 500 posts of real value, and about 1300 posts of attacks and self proclaimed victimization that not a single new person I've talked to is willing to suffer through to gain the value it contains. If we had a new thread that was kept a whole lot cleaner, and picked up where we left off, then it would be something I could recommend to people and they might actually read. Hence why I proposed a new thread to Paul in order to resume sending him data.

Quotes source post: 19854506

I look forward to reading your thread.

Quotes source post: 19854441

That is where the Scavenge pumps intake oil from so you can't fill that in....But those big cavities I show and mention above could be "stuffed" to keep from hiding valuable oil capacity that could be used in the Sump...

Crank carrier to oil galley sealant....

Quotes source post: 19854650

It's good to see the flair-up between Me and Baz resulted in this M96 improvement . Could you CNC a groove around there for an O-ring ? Would be much more elegant ,,

Quotes source posts: 19854640, 19854686

I was thinking we could either leave part of it open or raise the pickup point. But when you add latitudinal g's, it's a dumb idea. lol. I know the oiling path to cams, crank, and pistons pretty well but I've never taken the time to examine the return paths. My concern with opening the 6mm holes would be that it may allow oil to actually escape the sump in the turns. I think the two hidey holes I've circled in blue could be filled and save a .25-.33 of a quart. It's not much since they are only on one case half but it's not nothing. Red line is outflow to scavenge from the bottom end, green line is scavenge pump bath back to sump. We could but it would increase complexity without gain IMO. The loctite 574 takes two minutes, good for over 700psi, anaerobic, and will fill a 10 thou gap. It's really good stuff.

Quotes source post: 19854819

The 4 6mm holes in the IMS area ( I call it the "Z crossover" because it actually connects the bank 1 and 2 heads and oil will flow from one to the other through here) are in the center of the Sump from front to back so no oil will back flow into there during high-g cornering .. It could be "Swiss Cheezed" like shown in Purple ( I'll have to name something else ) to dump a lot of oil into the center of the Sump and not have to Pump so much back down which will have too good effects, 1 . will get more oil to the Sump quicker 2 will not be as aerated as going though the scavenge pump... The cavities in blue are pretty significant just looking at them and I haven't measured them but looks to me to be about .5 qts which is a LOT in my book ...

Wow, I slept on this thread and missed a bunch…Just to post my situation…I directly credit all involved Jason, Brandon, PT3, and all for the knowledge and intelligence to (knock on wood) get this subject to a level where I can confidently go out and track the spit out of my ‘99 996… 🙏🙏🙏 Slakker 3.7 Hartech Racing Sump 997 Oil Return Tubes (these provided a dramatic difference) SAE 60 Racing Oil OEM AOS My most severe condition is at the Carousel at Mid Ohio. Since I am there about 3 weekends per year, I can try different combinations of things. All data sent to Brandon for analysis.

Gents, great conversation. We need more of this on the forum. Glad we have been able to move forward. Brandon, appreciate your transparency with open discussions and your willingness to test and and post data. Quick question for you on cooling. A couple of years ago, Baz had discussed methods Hartech had used to improve water cooling during the rebuild. I believe it was to improve water flow around cylinders 5/6, but I may be wrong. Is that methodology still used and have any additional methods been put in place to further improve water cooling? Probably makes sense to ask the same question for oil cooling to see if any developments have occurred. Thanks