OK, I need folks familiar with the 3.8 that appears in the 1989 Turbo Trans Am (TTA), this is based off the drive train found in the Grand National/T-Type cars. And it's a race against time so a TTA makes it to the GM Nationals (leaving Thursday).

I know MCF is not persay the forum for this car, but I don't have a known account on better forums for it (nor does my friend) and to be honest, MCF has a lot of kick butt people with experience in all sorts of odd areas of mechanics! So I'm hoping to leverage someone here!

Here's the deal, 10 years ago this car was torn down for an oil leak (thought to be the rear main seal). Due to a long list of unfortunate circumstances it took 10 years to source parts to rebuild it and mod it. Sad part is, the original oil leak is still there.
We are talking the block and heads were completely torn down, a machine shop inspected everything before re-assembly.

From the best we can tell, the leak is on the back of the oil pan ( was under the car myself, the best all of use see is the back of the pan). Now, my friend thought it was the flange on the pan was damaged. We removed the pan. The factory pan has dimples on both sides of each bolt hole. He was using the Fel-Pro rubber gasket (has holes for the bolts and dimples). I read after some googling it was best to use a cork gasket.
Yesterday we finished installing a BRAND NEW pan (sadly, it's a deep sump pan and that baby hangs LOW). My buddy used a cork gasket. The stinkin thing is STILL leaking.

Worst of all, this leak is on the cross over pipe Huge fire hazard!

We have snugged the bolts as much as can be done within reason. Anyone, have any ideas!?!?!

Current ideas between my friend and I:
- RTV gasket sealant on both sides of the cork gasket, let cure over night, try and pray.
- Perhaps the oil system is building too much pressure. My thought, just for testing, pop the oil cap off (this should create a huge relieve of pressure).

Gang, we need ideas! We're running on empty! We will take off the wall, send them in!!

Update 6/17/2013: Oil Cap off, car still leaks oil. So I think that rules out a possible venting issue. Tonight, he's planning to goop it up with some RTV sealant. I have my reservations, so looking for more ideas gang.

Update #2 for 6/17/2013: I mis-understood, he did not try the oil cap off. But we may have a fix, please see post #9 for details. We will probably have another update tomorrow (and hopefully it's good news).

Update 6/18/2013: Bad news, he drove it to the place a bunch of us go for "Tuesday wing night" and it's still leaking! He's calling it, the TTA is not making it to the GM Nats.

 

Jason:
Sounds like theres waaaay to much crankcase pressure! You may end up useing a breather system and eliminate the PCV all together ..(If you havent already)....

How much oil pressure is pushing?.....It just may be pushing to much oil thru the system!

Maybe try some block sealer that you pour into the oil?....(Cant remember the name of it) Might be made by bardahl! Be sure to follow the directions exactly on the can. I have a buddy that swears by it!

I would eliminate the cork gasket (Never did have faith in them) and use neopreme ... RTV would also be a I think an excellent choice with it.. Just be sure to let it cure sufficiently!

 

Not sure about what the oil pressure is at. As for block sealer, we're staying away from that stuff (it's a brand new engine build, we should not have to do that). The cork gasket was a desperate move (as a few TTA and Grand National forums recommended that over the Fel-Pro rubber one).

The breather in place of the oil cap is what I'm leaning on (hopefully my friend tried my idea tonight an popped the oil cap off and let the car idle).

Keep the ideas coming!

 

Update: Oil Cap off, car still leaks oil. So I think that rules out a possible venting issue. Tonight, he's planning to goop it up with some RTV sealant. I have my reservations, so looking for more ideas gang.

 

My uncle has a 20th Anniversary 89 turbo TA with a factory inter-cooler if I recall... Sounds like the same setup, anyway, do you know what kind of oil pump was used, high output, or a high pressure pump? When the Engine was rebuilt, was it built to stock specifications, or were mods done to it? Same compression ratio as stock?

If you have a major pressure issue, no gasket is going to hold long term until the pressure issues is resolved;

you might want to take a peak here too:
129 PSI oil pressure???? - 3800Pro.com Forum

 

Ace, you are correct, my friends TTA is the same model 20th Anniversary your uncle has (very limited, something like only 1,550 made).

Anycase, bfore he got the car he was unaware that the engine was ever rebuilt, but since this tear down/re-assembly, it's clear the engine was rebuilt at one point (car has around 40,000 miles on it and he only drove it one year before ripping it apart).

In the re-assembly, I know he has modded:
- Rockers
- Longer push rods
- Cam
- Bigger Turbo

As far as I know, the oil pump is stock (I believe he replaced it while this mess was apart, but with a stock spec one). I don't know what changes were made to the compression ratio (I assume some were made with the modded cam and rockers).

We've been learning these Turbo Buick engines are known for oil leaks.... At least if they are rebuilt. I'd be happier if it did not leak oil on the cross over pipe.

BTW - I will take a look at the link when I get home. Thanks!

 

If you replaced the pan and gasket it has to be the rear main seal. Can you see it drip from behind the flywheel? If that's the case then your only option would be to goop up RTV somewhere to direct the leak elsewhere.

 

The rear main is also brand new (not saying it still couldn't leak, but it's been replaced). Read my next post....

 

First I was mistaken, my friend did not try the idle without the oil cap idea.

I just got back from my friend's place with the TTA. We have a theory and so far it's working!! Keep in mind, none of us are really skilled in turbo powered engines.....

He got thinking more about my oil cap idea and engine pressure. On the original setup, it had a breather (I assume for the PCV system) that goes from a valve cover to a connection on a tube that bolts to the turbo. With the new turbo, that tube will not bolt up and was too small (goes from like 3" on the filter side to 2.5" or less, his new turbo, 3" all the way).
Well, going with the pressure idea, he was wondering if the PCV tube needs connected in line with air going into the turbo, that perhaps this causes a "suction" or "vacuum" that is required for this engine. He went to the part's store and found a tube that could be put inline and prove this theory.
We ran this thing every bit as long as we did on the weekend, idled, revved it (and held it for a while) and the only drops we saw on the cardboard under it, residual from what shook off the engine with vibration. After one or two drops, NOTHING!!!

He's going to "pretty it up" with appropriate hose clamps tomorrow and hopefully drive it to "Wing Night" (a regular Tuesday gathering a bunch of us do).

 

Yes PCV is ran by suction. It equalizes the pressure caused from piston movement. Sounds like you got it right.