Topic: 82 Vette/81 heads and exhaust
in Forum: C3 Fuel, Emission Control, and Exhaust Systems
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Phoenix, AZ - USA
Joined: 6/12/2011
Posts: 139
Vette(s): 1982 corvette crossfire production numer C5101985. Color is silver and claret. All original numbers match. slight mods to crossfire for better efficiancy and power balanced and added fuel pressure assembly between throttle bodies,
Due to my car being mid year built i have the square holes in my exhaust which i believe are 81 small block type.
I have an exhaust leak and wanted some advice on how to correct it. I put gaskets on the driver side- were already their yes i know suppose to be metal on metal flush, anyways
they still chatter and are driving me nuts.
I dont have a shop near me currently to have them ground down flat and i cant go without my car. any suggstion on a good fix until i have an opportunity to take the manifolds off and get them fixed
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81' and '82 block and heads are basically the same, so I'm not sure what you mean by the exhaust has square holes. I'm assuming your speaking of the exhaust port shape.
Something you may want to look for…
If your '82 has the original exhaust manifolds they should be the tubular type. Like a shorty header not a cast iron ram horn manifold. '80 California only LG4 305 cu.in. vettes, '81 and '82's all shared the tubular header type design. The only big difference was the shape of the A.I.R. tubes going into the header. But there is one thing they do have in common….cracking. These tubular manifolds are prone to cracking over time. So it might not be the "flange to head" gasket leaking unless you can obviously see evidence of black exhaust soot. I remember they have heat shields around them, so you may not be able to see any cracks in them unless you remove them.
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Former Member
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Phoenix, AZ - USA
Joined: 6/12/2011
Posts: 139
Vette(s): 1982 corvette crossfire production numer C5101985. Color is silver and claret. All original numbers match. slight mods to crossfire for better efficiancy and power balanced and added fuel pressure assembly between throttle bodies,
Oh, i have square holes and the auto parts guy said 81. If they are cracked that means replacement.
Any good replacements that are direct bolt on without having to spend more on exhaust tube work? I'll take the shields off this weekend and look at them
Thanks
I don't think there is anyone reproducing those manifolds. You could try finding a good set on ebay, but thats a crap shoot.
Gary has a good idea. McJacks are nice headers. They do list a set of ceramic coated stock '82 manifolds for $695. Direct bolt in. No modifications needed.
Go to http://www.mcjackscorvettes.com/headerspage.htm click on C3 Corvettes and scroll down until you get to the stock '82 manifolds. They should be the second from the bottom set.
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I'm wid Sarge on the tube type manifolds cracking....usually around where the tubes all come together. If the noise is from a crack in a manifold, it will usually be worst when cold, then get a little quieter when hot, as things expand.
If the manifolds are not cracked, and you have trouble keeping gaskets from burning out, try this trick.....use regular paper/asbestos header gaskets. Soak them in water for a few minutes before installing them. Put them on, tighten the bolts, and fire the engine up....let it run for a while, or drive it around the block a couple o times easily. Don't drive it hard...just a nice easy cruise. Hammering on the throttle with the gaskets still wet has a tendency to blow them out....which is what yer trying to NOT do. Then re-tighten the bolts. 99.9% of the time this will FIX the flange leak problem. With the gaskets wet, they are softer, and will compress, conforming to bends in the flanges far easier than if they are dry. Once you heat them up, and dry all of the moisture out, re-tightening the bolts will completely seal the surfaces.
If the manifolds are not cracked, and you have trouble keeping gaskets from burning out, try this trick.....use regular paper/asbestos header gaskets. Soak them in water for a few minutes before installing them. Put them on, tighten the bolts, and fire the engine up....let it run for a while, or drive it around the block a couple o times easily. Don't drive it hard...just a nice easy cruise. Hammering on the throttle with the gaskets still wet has a tendency to blow them out....which is what yer trying to NOT do. Then re-tighten the bolts. 99.9% of the time this will FIX the flange leak problem. With the gaskets wet, they are softer, and will compress, conforming to bends in the flanges far easier than if they are dry. Once you heat them up, and dry all of the moisture out, re-tightening the bolts will completely seal the surfaces.
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Former Member
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Phoenix, AZ - USA
Joined: 6/12/2011
Posts: 139
Vette(s): 1982 corvette crossfire production numer C5101985. Color is silver and claret. All original numbers match. slight mods to crossfire for better efficiancy and power balanced and added fuel pressure assembly between throttle bodies,
thanks for the tip.
i looked at the tubes and their is no apparent cracking on them, the leak is comming from the
flanges to the motor. a friend of mine who races her camaro in the quarter mile said to try some high- really high heat silicone on both sides of the gaskets then put them on. said that they did this 15 years ago and havent had one problem with the manifolds.
ive got some exhaust wrap im considering putting on the manifolds while their off.
in Forum: C3 Fuel, Emission Control, and Exhaust Systems
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