I know Fiero owners port their exhasut manifolds and see a gain why shouldn't we. My question is now that my car sits in the garage excpet on those special days is it hard to pull the manifolds yourself without a air tool? Should I soak it big time with Liquid Wrench? Any advice by those that pulled them on what to expect...

 

I've pulled 2.8 manifolds off before, but never on my own car. I used a 20" long 1/2" drive breaker bar, with a 10mm socket. I'm not sure how people break sockets or break bolts when doing these guys! In fact both my spare sets of heads (one of which I took a manifold off of) had busted bolts. I was able to put vise grips on them, and turn the vise grips with my hand to remove them! I thought I'd at least have to use a hammer!

Yeah, soak the bolts with Liquid Wrench a few days before you work on them.

If you want to replace the bolts, and it's probably a good idea, the short ones are M8 1.25x40mm. The long ones are M8 1.25x70mm. The passenger side uses studs from the factory, but I think regular bolts could be used. I couldn't find the bolts at Home Depot, but I found them in the hardware section in a Pep Boys.

The hardest part would be unbolting your y-pipe from the manifolds.

As to porting the manifolds themselves, I had some messages up at the website that's in my signature. Basically, the walls of the stock manifolds are pretty thin, and don't allow for any "amazing" port job. However, the donut that goes between the y-pipe and manifold has a "large-to-small" step. In other words the exhaust gases have to go from a large opening to a small one before they get to the y-pipe: This sounds very restrictive to me. I have one spare donut, so I used an air grinder and a metal file on it to change the abrupt, sharp ridge into a minor, smooth hill.

I haven't tried the parts on the car yet.. I was going to, then I saw my cruddy track time. I think I mentioned it before, I don't want to do too many "new" mods before I fix whatever the hell is wrong now. Let us know how you do!


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

 

Oh - oops - Fiero guys see such an increase because their manifolds are in worse shape than ours. They have the single head-pipe with three pipes welded to it. In fact their manifolds look very much like an "E". It's at those welds where material sticks out into the head-pipe.

On our manifolds, we don't have any welds.. the manifolds are pretty smooth where the headpipe meets the pipes for the individual cylinders. There's still some porting that can be done, but I noticed that the minimum thickness of the walls are 0.25", and that doesn't seem like too much.

I'm not sure if Fiero owners have that donut-thing or a "real" gasket.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards