Oil Starvation

[The Radium King]

that's a cool tip. i checked on the auto atlanta parts diagrams and the part number has been superceded, which indicates to me that they have improved it for some reason. makes a person want to find out what all the superceded part numbers are, figure out why they changed, and incorporate if (a) cheap enough, and (b) easy enough. for example, the aos has changed several times. we hear all the time about aos failure but, given that this is the internet, you never hear what verson has failed. i'd love to find out the failure rate of the most recent version of aos vs previous versions; most likely the latest version is a significant improvement (ie, a motorsport aos not necessary).

[insite]

in this case, they replaced the 996 part with the 997 part. it has indeed been changed. the new piston has a chamfered edge, which usually is done if one suspects binding.

i'll post a pic of the different parts tonight.

[thstone]

I just ordered the EBS baffle. Looks like an easy to install solution. I'll put it in over Thanksgiving weekend so I won't have to worry about oil issues when I move from street to R-comp tires for my track days starting next month.

I also ordered a replacement oil pump spring/piston set just because its so cheap and easy to replace. With 98,000 miles I figure that IF the spring does lose performance then mine is probably gone by now!

[joni Hari]

Definitely watch for this. One of our employees left a mower running on a hill while he went to talk to someone and blew the engine on our brand-new mower!

[thstone]

I installed the EBS Racing oil baffle and replaced the oil pressure regulator spring/piston today. Took me about 3 hrs (took my time). Overall, very easy and a good afternoon project!

Here is the stock oil pan and baffle. The oil pan was very clean and didn't have any particles or sludge (a few small pieces of oil pan gasket material that came off when I removed the pan). Oil filter was completely clean too.



The one thing that I noticed about the stock baffle is that the rubber window shutter was kind of warped so it didn't lie flat along the baffle any longer. Not sure if this would have caused any issues but I expected the flaps to lie flat against the baffle windows to close them off completely.



The botton of the engine was very clean (much cleaner than I expected after 100,000 miles). The oil pickup screen was completely clear and clean.


Here is the EBS Racing baffle installed on the oil pan and ready for installation:

[tommy986]

It looks like your baffle already had the flaps to stop the oil flow. Are they all this way?

[insite]

tommy - they're all baffled, but the OEM baffles are rubber & deform / disintegrate over time.

[Jake Raby]

All these items treat symptoms, they do nothing for the underlying conditions that are the root of the true problem.

[Fyeganeh]

Originally Posted by Jake Raby

All these items treat symptoms, they do nothing for the underlying conditions that are the root of the true problem.

I assume you mean the root problem is many oils losing viscosity at high temps whereas Driven DT40 and the xp9 racing oil not doing so. I believe you don't think it has as much to do with lateral g-forces. (I have switched to DT40).

But my question is in a 15 year old car does the piston actually wear out/break and need replacing so as to prevent damage? Is it designed to last 15-20-30+ years?

Thanks,
Fred

[Qmulus]

Originally Posted by Fyeganeh

I assume you mean the root problem is many oils losing viscosity at high temps whereas Driven DT40 and the xp9 racing oil not doing so. I believe you don't think it has as much to do with lateral g-forces. (I have switched to DT40).

But my question is in a 15 year old car does the piston actually wear out/break and need replacing so as to prevent damage? Is it designed to last 15-20-30+ years?

Thanks,
Fred

The piston doesn't wear out, but the original is more prone to jamming in the bore, leading loss of pressure than the updated replacement. The question is whether the piston jams in the bore, resulting in bearing damage, etc., or if debris going through the oil pump and through the oil pressure regulator (relief piston), causes it to stick.

[Jake Raby]

The failure of the pressure relief system is very rare. The only time I have seen this lead to issues is when the pressure relief valve spring snaps in half (Mode of Failure #17).

The biggest issue is heat being absorbed by the clutch, passing through the flywheel, then heating up the rear main bearing. This leads to shear and wear, then wear debris of the rear main contaminating the rod journals of cylinders 3/6, leading to bearing failure.

[Qmulus]

Interesting. I have seen three blown 2.5l engines recently that had bearing failure, and ALL also had pressure relief pistons (early style) stuck in their bores in a position where the bypass port was open. The springs were OK. In that position the engine would not have had oil pressure. Did the pistons stick, resulting in low oil pressure, causing the bearings to be starved and the resulting damage, or did the bearing start to disintegrate for a different reason, as Jake describes, leading to the debris from the failing bearings going through the pressure relief bore (the oil is not yet being filtered) jamming the piston? Either way, I see no reason not to put in the updated oil pressure relief piston and spring. One thing that I have learned is that the Germans rarely say why they update a part (perhaps doing so would be the admission of a problem?), so it is a good idea to use the latest parts when possible.

FWIW, these all had LN deep sump kits and one had an Accusump. They also had lightweight flywheels.

I also saw an engine with a failing dual row IMS bearing (and no other apparent issues), which I thought was supposed to be unheard of, so maybe I am just seeing unicorns...

[The Radium King]

funny you mention LW FWs - jakes comment made me think that the issue with the lw fw is not vibration or unbalance, but rather lack of a heat sink such that cluch/transmission heat goes straight to the bottom end.

[Qmulus]

Personally I think it is a bit of a stretch to think it is heat. These cars had transmission cooling and temp data, and were not much hotter than engine oil. One had a recent clutch and the disk looked new with the part number stamp still present. Until I see data (MoTec has IR sensors that would be good for this), I am not convinced that transmission or clutch heat is an issue. ALL the bearings on these cars were damaged, not just rears, although those may have been the worst.

I am more inclined to believe that the flywheel/clutch assemblies were out of balance, putting more stress on the rear main bearing. IF that was the problem. Or the oil relief valve stuck (but why..) leading to lack of oil pressure, then the failure of main and rod bearings.

It does surprise me that people that are building these engines aren't using coated bearings or friction and heat coatings on pistons, combustion chambers, valves, etc. Heat and friction are the enemy of any engine, and these modern coatings make a significant difference. That stuff may not be legal for spec cars, but if _I_ were building an M96 I would definitely be sending some parts to Calico for it.

[Jake Raby]

There's no single factor that leads to these failures. Its an equation.

[Qmulus]

Originally Posted by Jake Raby

There's no single factor that leads to these failures. Its an equation.

Yes, a very simple one:

Lack of lubrication = $

[steved0x]

Quick question so I will bump this thread up - if somebody had an oil temp gauge installed, at what temp should they back off and/or come off the track? is there a safe(r) temp <= XYZ temp?

I just installed an oil temp and oil pressure gauge (pressure sensor replacing stock pressure switch and temp gauge in the matching port on the other side) - now that they are there, what do I do with them?

I have some ideas: like check the oil pressure after turn X on the straight, RPM is usually XYZ so see if the pressure is the same each lap at that point. Or check the temp at a certain spot and make sure it is at or below a certain value.

What is a dangerous temp?

Thanks

Steve

[BYprodriver]

Originally Posted by steved0x

Quick question so I will bump this thread up - if somebody had an oil temp gauge installed, at what temp should they back off and/or come off the track? is there a safe(r) temp <= XYZ temp?

I just installed an oil temp and oil pressure gauge (pressure sensor replacing stock pressure switch and temp gauge in the matching port on the other side) - now that they are there, what do I do with them?

I have some ideas: like check the oil pressure after turn X on the straight, RPM is usually XYZ so see if the pressure is the same each lap at that point. Or check the temp at a certain spot and make sure it is at or below a certain value.

What is a dangerous temp?

Thanks

Steve

As to max oil temp, a major factor is condition of the oil.

[cmacduff]

Steve-I think most would tell you that anything above 250 degrees is getting hot. I have oil and trans coolers on my car and it never gets above 215 even on the hottest of days.

As for the oil pressure that's a tough one. My car never gets below 35 PSI even in the most aggressive of corners( have baffle mods and oil return mods) but not only do you need to analyze oil pressure but you need to make note of when you are on and off throttle. Your pressure will drop in a corner if you are just entering and have been on the brakes. I have a Motec data system in my car so I can analyze my pressures and see the corresponding throttle percentage and usually when it's low I'm off the throttle.

I think that oil pressure info is good with the gauge you installed but may not completely tell you what is going on. What it will be good for is if you are in a long banked turn and can see it you can see where your pressure is at. Topless and Tstone are probably better resources than I but that is what I know......

[steved0x]

I am running DT40 (based on a conversation with Lake Speed Jr about the level and amount of my driving) and change it every 6 months which works out to about 2,500-3,000 miles. Uoa has been good with plenty of additive still left.

I don't have a data system but my phone app captures some, I am.going to mount it to get a view of the gauges and see how they behave when I'm driving.

I have an accusump but decided not to install it right away since I'm not doing Daytona this year like I thought.

Thanks for the guidance, so far the oil stays around 200, water temp at 180, I did an autocross Sunday and they went up some during my runs but came right back down.

Steve