Finally found the Trans Am's vacuum leak...

"Bandit" (2bandit) 04/13/2018 at 14:34 • Filed to: emma

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And it is slightly worse than I had hoped for. As you can see in the video, there are leaks on all cylinders where the head meets the intake. This was probably caused by some machine work I had done to the heads a couple years ago (where it had never run correctly since). The car has trouble starting, doesn’t like idling at low rpm when there’s no load on the engine, and is very down on power from what I would expect. Suppose the only thing to do now is drive it as is and save up for an LS swap.

Was given a case of this old castrol oil, figured the Trans Am could use it since the stuff is probably old enough to have zinc in it which will keep the camshaft happy. It’s a little less viscous than I would normally run, but the car will probably burn through the oil anyways before it becomes an issue.

crowmolly > Bandit 04/13/2018 at 14:50

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Man that’s a fast idle.

FWIW I see three listed Pontiac intake gaskets at Summit. Maybe the thickest ones with RTV can help? Heads were milled? If so, how much? 0.030?

Takuro Spirit > Bandit 04/13/2018 at 14:54

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More silicone bruh

punkgoose17 > Bandit 04/13/2018 at 14:55

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What kind of seal is this metal to metal with no gasket? Would Toyota 103 FIPG work, or would that be a bad idea?

Bandit > crowmolly 04/13/2018 at 15:04

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Under load it idles a lovely 700rpm. In park or neutral it ramps up to an insane 2000. Cant remember how much they were milled. I may try thick gaskets sometime. It cant be a huge leak as the car actually runs. Pulls about 5inHg on a vacuum gauge.

Bandit > punkgoose17 04/13/2018 at 15:05

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It’s got a gasket between them, but obviously it isn’t compensating for geometry mismatch.

crowmolly > Bandit 04/13/2018 at 15:06

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Don’t quote me on this, but .030 seems like it might be standard. Summit sells gaskets that are made to make up this thickness.

The Swedish Bandit > Bandit 04/13/2018 at 15:18

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Meh, looks like you need an aluminum intake anyways, so might as well change out to a better gasket while you’re at it. 

Akio Ohtori - RIP Oppo > Bandit 04/13/2018 at 15:28

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Thick gaskets + gasket dressing or RTV would be my first try. It isn’t the right way, but it would suck to have to redo the heads. Is it possible the intake is warped instead?

Future next gen S2000 owner > Bandit 04/13/2018 at 15:45

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LSA swap. You’re welcome.

Goggles Pizzano > Bandit 04/13/2018 at 15:51

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Your “saving up” could be shorter than you think. Don’t forget about this:

https://oppositelock.kinja.com/how-to-score-a-500hp-ls-engine-for-free-1131506504

Or this:

https://oppositelock.kinja.com/speed-on-a-budget-build-a-400hp-chevy-ls-motor-for-und-1125469009

Spridget > Bandit 04/13/2018 at 17:54

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Stock heads?

Bandit > Spridget 04/13/2018 at 18:51

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Stock Pontiac 6x heads

Bandit > Goggles Pizzano 04/13/2018 at 18:54

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The way I want to do it involves setting the whole thing up on a different, rebuilt, subframe (previous owner messed up a lot of the motor mount locations by welding in mounts). I want to put in a new transmission at the same time, preferably manual but T6s are really expensive and 4L60Es are dirt cheap and direct swap with my 700r4.

Spridget > Bandit 04/13/2018 at 20:24

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Seems like the perfect time to upgrade to aluminum heads/intake!