T&T Racing

IMO.
2nd engine failure: not thoroughly cleaning the block oil passages and oil pump and the camshaft tower as a secondary cause.

1st engine failure: probable cause is not torquing the oil pump pickup tube nut o Porsche specs.

All of these are correctable. HFerris posted the procedure on using a crowfoot wrench to access the nut.

I am sure your next build is going to last with your learning experiences in hand.😃

harveyf

The failure of the 1st engine is a mystery, as it seems you did a first rate build. VIR is my home track. I've done hundreds of DE laps there in everything from 40 degF to 105 degF. I've never had a problem there. The track is good in that there are no really long sustained g turns. But being DE, I usually pedal it on the straights whereas you have to go hard. And those are long straights. I also run Valvoline VR1 20-50 full synthetic with a Mann filter. And like you, I tend to replace after every other event. I shift around 6000 most times but will take it to the rev limiter when I loose track of where I'm at! Since you have run various oil pumps there goes that theory. So I can't spot any obvious problems. It may just be a matter of you will need to replace the rod bearings every season.

You might want to get a data logger and track your oil pressure. I use a Race Capture Pro from Autosport Labs.

I don't know if the 924 has it but my 944 block has a third oil gallery plug, at the bottom of a vertical gallery, that I overlooked until I finally realized it was there. Crap can hide in there.

CrookedRacer

Thanks folks.

I took the cam tower off because it seemed a lot of the noise was coming from the top end, but it was beautiful. No evidence of oil starvation. Clean oil. Smooth spinning. All lifters rising and falling easily with the cam. No metal flake, no residue from the milkshake, not that I saw any before.

So I guess now I’ll just take off the head and see what the bores look like.

CrookedRacer

My next build will have just such a data logger. And an oil temp gauge. With the sensor right at the filter.

Can anyone recommend a sensor/gauge setup? I saw a sandwich adapter by Perrin that looked like it would fill the bill. Any other ideas?

T&T Racing

FWIW: my AIM data acquisition system has the oil temperature sensor in the oil pan. The 944 2.5L NA oil temperature runs about 190 - 200 F in a race and oil pressure is 90 psig. The oil pan and pickup tube has the mods listed in your engine #1. I do not change oil after every 2nd event. Change oil once a year, but if did more events, then twice a season. The Blackstone Lab oil analysis is my bible for how the bottom end of the engine is not going into failure mode.

Noahs944

Crooked Racer, I commend you on your persistence brother. I know how frustrating this must be. What type of oil filter do you use?

wildcat077

PM me your email and i'll send you a few pics of how i have my oil temp probe directly plumbed in to the oil pan ...not the drain plug , but the one on the opposite side , that way you get the exact temp of the oil
as it goes in the engine , not before it goes through the cooler and filter.
My oil temp runs constantly @ 190 degrees , pretty much the same as my water temp and the pressure is a steady 70-80 psi during a race, and my engine cutoff is @ 6700 rpms.
I'm using Amsoil Dominator 15w50 and altogether my engine holds 8 liters with the cooler and lines.

Yes , it's a full race engine with the big Lindsey Racing oil cooler, ishihara crank scraper,oil pan baffle ... etc

Let me know if i can help !

thomasmryan

When you pull to the limiter, hard, in the lower gears, is the rev limiter a soft limit? I could see an abrupt rate of change in the jerk, or the next derivative of acceleration, working the oil pump drive loose just a little. What does the intermediate washer on the oil pump drive look like? Is it polished some?


You you said you had swapped these drive parts over from the old motor so just being curios.

T&T Racing

Engine #1 Failure. Is it possible that the connecting rod was not installed with the proper orientation with respect to the front of the engine? The connecting rod bearings have tanqs in both the lower and upper half bearings. The connecting rod can be installed in the piston with the tangs oriented to crank rotation to prevent spinning or rotated 180 degrees with tangs oriented where the rod bearings can spin over time .

Mikelly

MY car came plumbed like this and my AIM dash displays my oil temp from this port. I pick up oil pressure through the stock port on a VDO 10BAr pressure sender and log both, including coolant temps at the vent port on the upper radiator hose to engine mount.

I race with John (Crooked Racer) and have been following his build and process for a while. I was sad when the first motor let go. I was really sad when the second let go. I agree with another poster concerning replacing the oil pump (Instead of rebuilding) and thoroughly cleanring all the suspect donor parts from both motors on the second build. John was trying to make Hyperfest, which is a big deal in the NASA racing community, so I get why he cut a few corners., However, those corners are why I think ONE MORE engine build done with care, patience and extra time, is warranted.

Mike

Oddjob

From the above comment, I am not clear how full you are running the oil level - what do you consider the "right level" on the dipstick? How often do you check the level during a wknd event/race?

Sorry if I missed this in previous posts - What track(s) were you running the car at? Types of corners, high speed/high G, low speed, right/left turns, banking?

wildcat077

I can say for a fact that my 86 N/A with the large Lindsey front cooler and both -12 braided lines holds exactly 8 liters at the full mark on the dipstick !
Seems like you have pretty much the same setup, so 8 liters should be pretty accurate for you as well ...

This is a fresh engine build with no residual oil in the cooler or lines as i had them flushed and steam cleaned prior to reinstallation !

ealoken

On my 951 i had both Oilpressure valve failure and o-ring failure on the pickup.

I ended up porting the oil gallery to rod 2, it has a gnarly bump where the oil needs to turn 90 degree.

What oilfilter are you using? Does it have a bypass?

curtisr

Would a dry sump system or an oil accumulator be of value here?

CrookedRacer

Ok, so I have some more information about the second engine failure, but the cause of it is still a complete mystery.

First, I took the Oil Pressure Relief Valve (OPRV) out, and inserted the new oil cooler alignment tool that I bought into its opening. It threaded all the way in with zero resistance. So the 951 oil cooler console is (and was) properly aligned.
The OPRV looked fine as well. Its piston at the tip pushes in smoothly against the internal spring's pressure. There was no debris or flakes or gunk in or around it. It pretty much looked like it did when I put it in.

Second, I drained the oil into a clean pan to see the oil's condition. It wasn't crystal clear, but it didn't contain large shimmery flakes, either. I guess I'd describe it as a good amount of black "soot" - very fine black sediment. There's a blob of that sediment on the magnetic drain plug but it's no worse than I've seen on any other engine. It's pretty much what I'd expect from the first oil change after a rebuild. The oil smelled normal.

The oil filter I was using was a Mahle OEM. In the past I've used K&N, Brad Penn, and Mahle.

So none of this really gives me a clue as to what caused all the noise. It makes me think the bearings are intact. What else makes horrible noise? Could be the rings. Next I'll have to remove the head.

I'm taking my time on this for my sanity's sake, but I'll keep you posted. Thanks for all your input!