mumzer

So...recently changed out the cylinder head on my 951 with a Lindsey racing prepped head. After a few days of driving, and tuning, I pulled the plugs to confirm what the AFM had been showing me, and discovered an oily mess.

The first few threads, center electrode and side electrode show all the signs of oil fouling (ie wet and black). Plugs 1 and two are considerably worse than 3 and 4. The quantity of oil is pretty significant.

there are a number of possibilities;

1. head gasket seal--i have no mixing, no milkshakes and no overheating...this seems like a longshot;

2. Bad valveguides...well i guess this is possible, but the damn thing is brand new...i'd love this to be something else...

3. ring seal...motor is a highish mileage 2.8...bores are far from perfect...I have pulled the crankcase vent from the inlet side of the turbo, and after two days of driving, (normal city driving with a few hard pulls) the thing has only pukes a teaspoon or so of oil into my catch can...so this could have been contributory, but the plugs are still oily; and,

4. turbo seals...its a k-29-8...it has only been n the car a few months, but has seen some significant track use...the discharge tube from teh turbo to intercooler had accumulations of oil when i pulled it off...inside of the pipes were wet, and the rubber adapter hoses had small pools of a few ccs of oil in them. Inside of turbo volute seems to have a wisp of a puddle in it also...the inside of the intake manifold is wet...no pooling oil, but a patch of cloth will come away moist if its pushed into the intake.


What do you guys think...seems to me that the turbo really should have no oil in the cold side, once the crankcase vent is discconected....any easy way to test turbo seals without pulling it all apart?

any thoughts here will be welcome.

I should add that the car very recently started smoking on high rpm pulls and on gear changes...it does not smoke on start up...which seems a bit strange to me since the plugs are wet when i pull them after shutting down...

Jeremy Martin

do a compression test on all cylinders; then a leak down on all cylinders if compression isnt uniform or generally low. if that all checks as normal, it's the turbo seals. have you noticed black smoke from the exhaust? if the turbo isnt smoking chances are it's fine... and i mean smoking most of the time, not just under acceleration (although you should only notice a black cloud under acceleration from running rich, not a blue cloud)

special tool

Definitely oil, eh Mumzer? Carbon deposits from an overly rich mixture look a lot like oil...

mumzer

[quote]Originally posted by special tool:
<strong>Definitely oil, eh Mumzer? Carbon deposits from an overly rich mixture look a lot like oil...</strong><hr></blockquote>

definitely oil.

special tool

Got to be rings then, don't you think? The new head pushing on them a little bit harder.

mumzer

well...jsut checked compression...motor BARELY warm makes between 137 and 150 psi on all holes (bear in mind that its a long stroke 2.8 so the CR is higher)... so id say that ring seal or valve seats are not the problem....

next guess?

special tool

Looks like you have eliminated everything but the turbo. All I can suggest is to put the case vent in the can again, and let the thing boost hard and often to positively eliminate that also.

mumzer

thanks...i'll try the breather...im going to have a little tete a tete with the clown who sold me the turbo...its got less than 10 hours on it...

Perry 951

Was this race prepped heads complete with new brass or bronze valve guides? If so, they take a while to seat in.

New seals can leak for a little while too.

Now, if the turbo has **** the bed, then you found your problem.