Oil spurting from somewhere under the intake...

[mikepellegrini]

My kid's (Travis - Trivgar) 86 951 has had a problem with oil use for quite a while - he's been going through as much as a quart every 50 miles! When he boosted, it was like a James Bond smokescreen - but only when he boosted. This started maybe 6 months after he upgraded the turbo.

It runs just awesomely. Scary awesome! There isn't any oil in the hard pipes, and his plugs looked relatively good, so we were tentatively figuring a blown oil seal on the hot side of the turbo - where it was dumping oil directly into the exhaust.

Maybe 6 months ago, his No. 2 plug fouled, so he went to a higher heat range. Everything was just nifty after that, although it still used major amounts of oil.

In the last couple months, we began to notice a lot of oil on the top of the engine, under the intake manifold - covering the vacuum tubing and everything. Initially we wrote that off to his having over-filled the oil, by mistake.

But the oil on top of the engine has continued, and then last week, his No. 2 plug fouled again. It looked pretty icky:



We decided to do some testing.

With the intake manifold off, it registered 150 PSI (engine hot) all the way across (+- a couple PSI). With the intake manifold and throttle body on, No. 1 registered closer to 140 PSI - but they're all very close to equal (and that wouldn't be affected by the manifold being off).

A leak down test was inconclusive (the guage was broken) but we were able to listen and there was no leakage at all from the top end; you could hear some hissing on a couple of the cylinders listening at the oil filler tube.

Here's a picture of the top of the engine; the arrow shows the direction of the splatter pattern:



A closer look at the intake port for No. 2 shows a large accumulation of oil:



None of the other intake ports showed as much, although No. 3 had a little:



The other plugs all looked relatively good.

Anyone want to make a stab at a diagnosis? The only thing we can think is that the oil is coming from the crankcase ventillation or maybe the oil/air seperator has failed. It isn't the cam tower gasket - it's nice and dry - he replaced that last summer.

Anyone had a problem similar to this?

The mods on Trav's car include:

Lindsey Racing Stage 2 MAF with a piggyback controller
3 Bar FPR
951Max Chips
75# injectors
Lindsey Racing Super 65 Turbo
Open Tial 38mm dual port wastegate
Innovate LC-1 Wideband O2 sensor and digital AFM gauge
Lindsey Racing Manual Boost Controller
Lindsey Racing 3" cat-less, muffler-less exhaust with a resonator
Koni adjustable struts with adjustable ride height with 425# springs and solid strut mounts
Koni adjustable shocks with 550 # Rear Coil-overs (torsion bar delete)
KEP Stage 2 clutch and pressure plate


Additional pictures: Cars

[Techno Duck]

How did the intake manifold gaskets look? I had a similar oil thig under the intake that was caused by a blown out gasket. If the cam tower is not leaking that's all I can think of unless the crank vent hose is badly cracked. What does the compressor of the turbo look like, covered in oil?

[Techno Duck]

BTW, the fouled plug is either worn out valve guides, leaking stem seals or the rings are shot. You probably just need to have te head rebuilt. A hotter plug is a temporary fix for oil fouling, it just takes longer to get bad.

[Rasta Monsta]

That is a horrible looking plug. I say HG is suspect, leakdown and coolant pressure test recommended.

[mikepellegrini]

The car has never overheated and it runs just great - with great compression.

Like I said, the leak down guage was broken so I couldn't get a percentage of loss, but you couldn't hear much going on inside the engine except from the oil filler on a couple cylinders - and it wasn't real loud. And that's using 100 PSI of pressure.

If it was the valve guides, I'd think it'd be sucking oil when you let off the gas, not having it billow out smoke on boost. Another sign of bad valve guides is where you get a lot of smoke initially when you start up - and it doesn't do that.

If it was bad rings, you'd think the compression would be a whole lot less. 150 PSI straight across (no differential) is awfully good - too good for bad rings, I'd think.

And while the compression did not vary by more than 5 PSI in all cylinders, it was only No. 2 plug that fouled.

The gaskets for No. 2 and to an extent No. 3 were soaked in oil - but completely intact. We did Trav's cam tower gasket last summer so the gaskets were close to new.

The hard pipes and the cold side of the turbo are completely clean.

So like I said, the only thing we can think is that the oil is coming into the intake from either the crankcase vent pipe, or something like that. I gotta study the plumbing. If it turns out the vent pipe dumps out close to the runner for No. 2 cylinder, then maybe we have a winner. Although if it was that, I'll admit I'm not sure how to fix it.

Do these cars have a PCV valve or is that what the oil/air seperator does?

[Techno Duck]

No PCV on these cars. The smoke on boost out the exhaust is the hotside seal, which is sorta like a piston ring. What mileage do you have on the top end? I still suspect your head needs to be rebuilt.

[trivgar]

The top end was supposedly rebuilt before I bought the car. Maybe 25-30k miles ago.

[mikepellegrini]

Okay, more pieces to the puzzle:

• the vacuum intake port (on the manifold) closest to the throttle body has oil dripping from it (appears to be the one from ISV)
• Runners 2 and 3 have oil dripping from the inside (of the intake manifold)
• the inside of intake runners 1 and 4 are clean inside
• The out port on the ISV is coated with oil ; the intake port on the ISV appears to be clean (oil magically appears on the out-port?)
• There's a lot of oil around on top of and beneath the Oil air seperator

Herer's a good picture of the splatter pattern on top of the engine:



A link to the hi-res original pic: http://www.69Workshop.com/album/oil5.jpg

Looking at the wet and dry areas of the hoses, it looks like the oil is coming from both the ISV (!?!) and the O/A seperator, kinda. How, I dunno - cause it doesn't really make any sense.

The greatest amount of oil is right around the radius of the O/A sep.

Somehow it's getting sucked into the intake and is fouling No. 2 plug?

[Techno Duck]

Do you have the hoses for the ISV and crank case vent correct, it's not uncommon to swap the two, putting the crankcase vent hose on the intercooler pipe.

[mikepellegrini]

Pretty sure. An d the oil use didn't increase till maybe 6 months after he installed the new turbo.

[Techno Duck]

Reversing those two lines can cause the two problems your having. Pressurizing the crankcase will cause excessive blowby past the rings and foul the plugs. Also it can kill the hotside seal on the turbo by restricting flow back into the pan. The turbo is a gravity drain, no pressure on the oil coming out of the turbo. That would explain your excessive smoke on boost.

Just a thought, it's not hard to swap those two lines mistakenly.

[mikepellegrini]

The ISV hose went to the #1 vacuum port on the intake manifold (in front, closest to the throttle body); the OAS hose went to the port on the MAF (would have gone to the J-boot on stock setup?).

[trivgar]

Which is correct. But what's connected to my cold intercooler pipe. The recirc anndd where does the other hose go?

[trivgar]

To the isv? I guess if that's the case they're all routed correctly.

[nize]

the upper balance shaft is near there. could it possibly be leaking oil between the balance shaft cover and the block? oil is pressurized there, so it could be shooting out, making it seem like the leak is elsewhere.

[mikepellegrini]

We looked at the upper balance shaft cover this morning and it appears to be tight.

We also verified the o-ring on the oil filler cap was there.

We did another compression test this morning with the engine cold (the intake manifold is off so there was no other option). First we did the compression in each cylinder dry, then added a couple capfuls of oil and did the test again. Here's what we found:

........ #1 .. #2 . #3 #4
Hot ... 150 150 150 150
Dry ... 142 145 148 150
Wet .. 160 180 180 170

That's quite an increase in compression with the oil in the cylinders. #2 was the plug that was fouling. But does that suggest the rings are bad?

I was surprised by the small difference in the hot and cold compression numbers. And I would have thought that the compression was awfully good for bad rings.

I'm getting a new leak down tester today and will report back on what kind of leakage we get - we oughta be able to test it at latest tomorrow.

[mikepellegrini]

Okay, we performed a leak down test on Trav's 951 this morning. The engine
was cold because the intake manifold is off. Here's what we came up with:



At 100 PSI on cylinder No. 3, when Trav put his hand over the filling tube
(trying to block it) it whistled - there was that much pressure escaping.

The results of the leak down test seem to be at odds with everything else.
I woulda thought the compression was way too good for bad rings.

But you put two capfuls of oil in each cylinder and the compression in three
of the cylinders rises between 20-35 PSI which suggests ring problems in
those cylinders. But the leak down test shows an appreciable loss (28%)
only in cylinder No. 3.

What gives?

Other than the one intake valve hissing, the only other noise audible during
the leak down tests came from the oil filler tube; no noise from the coolant
reservoir or tail pipe.

The original problem you'll remember was plug No. 2 fouling and also oil use
generally - a quart every 50 miles, with quite a bit of smoke (think James
Bond Smokescreen) out the tailpipe on boost, and a lot of splatter on top of
the engine under the intake manifold centering mostly around the OAS.

Try this scenario: bad rings in Cylinder No. 3 pressurize the crankcase
which causes the OAS to fail which sends oil through the vacuum system
intake and fouls plug No. 2 - at the same time - as he has a failed oil seal
in the hot side of the turbo which causes oil to dump into the exhaust.

There's no other way I can imagine using a quart every 50 miles - not with
just one cylinder with bad rings. There has to be something else and a bad
oil seal on the hot side of the turbo would explain it.

Trav's got the Lindsey Racing Super 65 Turbo which is oil cooled. It drains
by gravity, right? If the crank case was pressurized, it wouldn't drain?
Which could cause the oil seal to fail? Does that make sense?

The only other test I can think of would be to put the car back together and
then measure the crankcase pressure at the dipstick tube. If everything is
working properly, there oughta be a slight vacuum at the dipstick - correct?
But if there was positive pressure, that'd confirm at least the bad rings?
(or you could just take the filler tube cap off and block it and see if you
could feel the pressure).

What do you guys make of this?

[Rasta Monsta]

Originally Posted by Rasta Monsta

That is a horrible looking plug. I say HG is suspect, leakdown and coolant pressure test recommended.

I dunno, I think this guy's comments make some sense.

As for the "excessive crankcase pressure = turbo drainage issue, seal failure, and smoke" theory, that is an affirmative. DON'T ask me how I know.

(By the way, HG failure can also lead to excessive crankcase pressure. . .coolant isn't the only thing to pass through the HG)

[jerryw]

I don't know if you checked - but on my N/A spec car I was having a very similar issue with oil spray under the intake manifold and tried all the standard solutions Oil/Air separator seals, re siliconed the upper balance shaft housing etc etc. It eventually - on my car - turned out to be the cam tower housing gasket.

But that doesn't explain the fouled plug - maybe the 2 symptoms are not connected ?

[mikepellegrini]

We just did the cam tower gasket on Trav's car last summer, so we're pretty sure it's not leaking there. I took all the crap off (ISV and other vacuum turbing) and you can see the line between the head and the cam tower pretty well - it looks good and dry.

We got a friend of a friend who is a master mechanic to review the symptoms and what he came up with was:

"Burnt valve #1. Vac test should verify. #3 probably has fracture in ring
lan and/or broken ring. Can test for pumping compression test with bad
rings. Would normally suggest using a blowby meter, but if leak test was
28%, no real point. Cylinder is bad. Oil consumption is most likely due to
the pressure in the crank case backing up the turbo drain line and not
allowing oil to drain. I agree with Michael. The oil in the CHRA is being
pushed into the turbine housing. I would suggest a rebuild. At minimum, new
valve(s) and a re-ring kit. But inspection of piston 3 for damage.
Especially around the ring lan. The oil scrapper rings are likely all shot."

From this and what you guys have given us, we figure that's enough confirmation of the diagnosis, so we're gonna pull the engine - in a couple of weeks.

Before we can do that, Trav has another project he's gotta do - an 82 Chev S-10 pickup he got for free. About 5 years ago, the PO started to install a brand new engine (as in new from the factory) , with a new clutch and transmission - but then stopped before he got it done. The truck set out in his pasture for about five years. The guy had to get rid of it a couple months ago (He had to clean up his pasture) and Trav got it for the price of a tow.

The body is straight but the paint is really oxidized. The new engine is maybe 90% installed (the clutch and trans are in). We're hoping to get it running this weekend - then Trav can sell it to finance the rebuild of his 951 engine...

It never ends...