Help Diagnose Oil Leak?

[Tangles]

After help with diagnosis.

Had a track day on 11th April, track car was not ready so couldnt pop the cherry with my rb26dett sedan track car. Wasnt happy.

Took the stagea out for the day to mallala for the 4th time, always said I wouldnt run my road car there again but had no option in this instance (paid fees, couldnt waste the $)

Started the day with around 5.5L oil in engine.

Right at the end of the 2nd session (20mins each session) at the end of the straight on deceleration (as soon as foot came off accelerator) there was a MASSive cloud of grey-white smoke out the exhaust. Big smoke ball.

Get onto 1psi boost and smoke everywhere again.

Emptied catch can, cleaned oil up from engine bay, tried again next session but as soon as positive boost pressure was made smoke billowed out the exhaust again. Called it quits for the day. On the drive home anytime it reached 1psi smoke was clouding out the exhaust. Oil could be seen spraying out the T3 housing where the exhaust manifold meets the turbo. I thought "turbo oil seals" so took the turbo off. I had the turbo checked out by the manufacturer (Adelaide turbo services - ported nissan comp cover, avo .73ar rear housing, gt3076IWBB chra) but they said it checked out perfectly fine. There was oil through the air filter, and throughout the intercooler piping, cooler had a few hunded ml's of oil in it. Even the throttle body had oil pooling inside.

So, its not the turbo. There is no milkyness to the radiator fluid, nor to the engine oil. So that probably excludes the Cometic 87mm 1.1mm MLS headgasket being the problem.

Since I changed the oil & water (after turbo removal/reinstallation) there is no more smoke billowing out the exhaust on positive boost pressure.

However, the engine is leaking oil onto itself and burning as soon as it gets a little warm, it stinks of burnt oil. Smoke comes out the engine bay. The engine block has oil residue all over it, everywhere. Upon shutdown oil drips for a little while creating a small pool underneath the engine on the ground.

Just had a proper compression tester kit delivered today, so tomorrow will comp.test the engine, however there is no noticeable knock, ticking etc. Seems to idle just slightly more "lumpier" than before. In the meantime, prior to having it left at my mechanics, what do you think Ive broken?

Im thinking out on the track far too much oil got stuck in the head, couldnt return to the sump, and found the weakest point to escape.

Would this be the rocker cover gaskets? What / where should I start checking?

So, in a nutshell, oil coming out of engine when warm, burning on engine, stops leaking once engine is cool. What gaskets should I be checking?

Waiting on track car to be tuned and finished, then will swap stag for track car and have mechanic check it out. If I could fix it I would but not sure where to start. Plus Im a registered mobility disabled person, so taking off the turbo is a huge job for me. Takes me a week to recover from a simple 2hr job. Hesitant in taking off the head as it'll ruin me, and definately cant work on the intake manifold as there just isnt enough room for me to work around in (ie big hands in little spaces)

If oil was stuck in the head, filling the head completley and simply needed a way out - where do you think it would escape from?

cheers for any thoughts, post up your diagnosis.

ta.

** engine is Rb25det with stock bottom end, everything else aftermarket (ported head, tomei poncams, etc etc)

[DVS JEZ]

Do a comp test 1st

[Tangles]

yup. will post results tomorrow. had to wait a cple of weeks before I could buy one.

[Tangles]

so I tried a cold-start dry compression test, turning over the engine for 10 cycles.

bore #1-4 + #6 showed around 80psi dry/cold

bore #5 showed 0

turned over engine for 18 cycles for #5 and showed around 35psi dry/cold

could tell from the spark plug prior to comp.test that piston 5 was not right.

strip down time.

[LeD ippen]

same thing happen to my friend in honda. though pvc and catchcan setup overfill and messed up got into intake. so detonated, blew rings and pistons

[Beer Baron]

wow, it is pretty severely fked. low comp in 5 cylinders and nothing in number 5. just one thing is the comp tester screw in or one of those god awful push in ones? even with a MLS head gasket and cams that figure is very low so I think your prognosis of strip and rebuild is probably correct. bummer.

[Tangles]

that was a cold cold engine, dry bores

will do a warm compression test once battery is recharged.

there was a common consistency across cyclinder 1-4+6, same with the plugs, #5 however isnt healthy

...even if the difference between warm & cold comp test is 40psi, the cold-start comp test tells me the bottom end is tired.

the comp.tester is brand new, proper screw-in type, works brilliantly

[gotRICE?]

Hmm. It is an interesting situation!

If the car still runs relatively well, and only appears to bellow smoke on boost then i would guess that #5 has just blown the rings. Just seals on normal driving, but anything more than atmo pressure and its fubar.

Looks like you and the mad scientist gotta rip apart the block, and replace the piston rings you just fried.

While its out, replace the rocker cover gaskets and the half moon seals. 25s tend to leak from the rear, and you cant see it. I know mine does. I get a bit of oil moisture forming on the bellhousing lol.

[SargeRX8]

What would have caused this? Heat? Oil quality? Lack of fuel? Detonation?

Edited May 12, 2011 by SargeRX8

[Tangles]

cause: previous track time engine overheated - boiled the fluids.

this track time engine probably over oiled, oil on afm, detonation perhaps from fuel-mix, FCD overides AEM F-ic8 piggyback which overides remap ecu...

being a stagea auto it was to be expected I guess, having being leaned on a bit to produce 350rwhp

currently doesnt bellow smoke, but then again I havent given it much whatsoever since the incident. 100kms driven since, sedately. oil is leaking & burning away, engine bay has a black 'grime' around the place

perhaps Rb30 bottom end time. we'll see.

[DVS JEZ]

No good man. Sorry to hear.

When doin a comp test on RB's its best to start at the back. So u dont get ur hopes up when starting from the front.

Ive been there done that.

When u put your next engine together thats going to see the circuit get an ecu that has inj trim per cylinder. Or atleast flow check ur injectors and put the highest flowing inj into the rear cylinders to help keep em cool

[Tangles]

i'll be dropping off the stagea to my mechanic, and picking up my track car

rb26dett brand spanking fresh rebuild, 87mm pistons, pfc with 550cc inj. track car

turnkey was this week, picking up in a days time or so for the run-in period.

so yeh, as said in original post, wasnt keen to track the stagea that one last time, did anyhow, and have to move on with it.

[DVS JEZ]

I read that. Definately sucks balls