Replacing gaskets in left exhaust manifold. Help!
 

I brought the car to a hobbyshop to use their lift, tools, etc and once they found out I was trying to remove the left manifold they immediately told me to stop and spray the bolts down with basically a supercharged WD-40 , breaks down rust, loosens bolts...etc...etc for a few days then come back and remove the manifold. The ticking sound is really getting to me. I've been driving the car daily since early August and been plagued with the exhaust manifolds leaking. The right side was fixed last month at a shop and now the left side needs the gaskets replaced as well. Due to the EXTREMELY expensive fix price from quite a few shops around the area, I decided to try to do it myself. I'm not the most mechanically inclined person but there is nothing on this car that I cannot learn over time. From asking around I have heard many people say it's not that hard to do except for the bolts breaking. It seems to me that is the worst case scenario yet it happens alot during the process. I've been getting the you'll be screwed if the bolts break, but you can tap it...do this...do that...and pray it works. I really don't like the odds of the bolts snapping while I attempt to remove them. The manual I have doesn't give a good description as to how to remove the manifold enough to slide the gaskets in and so I have come to my corvette family at corvetteforum.com for words of wisdom, tips, and hopefully how to's.

I have been spraying the bolts down everyday and will continue to do so for 5 more days when I get a chance to have at it. Anyone know of a website with good description on how to perform this surgery on my car? I would be more than happy to just read some how to's from a forum member. The leak is the only major problem I have with the car and once it's fixed I can finally feel what its like to drive the car with most to all of it's performance intact. It's real sluggish now compared to when the manifolds were not leaking. Help me ol' wise masters of the sacred Corvette, for I am young and inexperienced. As always thanks in advance for helping me with my 1979 Corvette. :smash:

Re: Replacing gaskets in left exhaust manifold. Help! (Phoenix79)
 

Just wondering, are you talking about the exhaust manifold to head bolts or the exhaust header pipe to exhaust manifold bolts? Chevy did not use gaskets between the manifold and the head.

When I pulled mine off I guess I got lucky. On the header pipe fiting, a couple of the nuts would not come off but the studs unscrewed from the exhaust flange. Just had to replace the studs with new ones.

tom...

Re: Replacing gaskets in left exhaust manifold. Help! (Tom73)
 

It's the exhaust manifold to heads...a lot of people have said the same thing to me but for some odd reason my car has gaskets. Maybe the previous owner had some problems, who knows...I just know the ticking is terrible and that nasty exhaust in the cockpit smell after stopping from a short drive is making me worry about my health. I do have the doughnuts for the pipe to manifold as well and plan on replacing them too.

Re: Replacing gaskets in left exhaust manifold. Help! (Phoenix79)
 

I pulled my mainfolds last winter as part of an upper end rebuild. Used common shop tools and didn't need a hobby shop. Had the heads and manifolds mating surfaces machined, so reinstalled without using gaskets -- no leaks. GM didn't use gaskets for the reasons you're suffering now. They work for a while, then start annoying burn-through leaks.

But that's the long term fix. If you have a leak, then you may have a surface imperfection on the manifold mating surface. I'd allow a couple days for the job and as a minimum have the manifold surfaced at a machine shop (while you're at it, you can have it baked and refinished to look really nice for not much money). The best solution is to pull the heads and have everything resurfaced, then install back to factory specs with no exhaust gaskets. But to temporarily stop a leak, gaskets should work. By the way, the gaskets usually have a metallic side and an asbestos fabric side--install with the metal side out--towards the exhaust manifold.

I surprisingly had no problem with the manifold bolts--26 year-old original bolts, came out without any problem. While the ends look rusty, the threaded area was tight and rust free.

Follow Hayne's for proper torque spec and torque sequence, to avoid cracking the manifolds.

Not too much interference on the driver's side, but if you have A/C, the passenger side manifold is really a bear to reinstall.

Lastly, find a shop that sells stainless steel french locks to install just under the bolt heads, then you bend the tabs over the bolt head for the original factory appearance--as well as ensuring the bolts don't come lose.

Cheers, :cheers:
Dave