Manifold gasket replacement
Thread Starter
Instructor
Joined: May 2019
Posts: 103
Likes: 13
From: Near D.C.
Manifold gasket replacement
I’ve got a small exhaust leak from where the manifold meets the block, on the passenger side. Thought this would be super simple, but looks like I might have to remove the a/c compressor to get the manifold away from the block? Just want to see if its possible to complete this without removing the a/c compressor. Also, I saw some one mention avoiding using the gaskets and use the sealant instead. Any input on this? I have a ‘77 with the stock manifolds. Thanks!
Race Director
Joined: Nov 2006
Posts: 13,195
Likes: 7,795
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
Unbolt the compressor, but leave hoses intact. just lay it or wire it off to the side.
Exhaust manifolds are bolted to the heads. Not the block.
get under the car and undo the 3 nuts holding the pipe to the manifold. just pull the pipe down an inch or so, just enough to clear. now is a good time to get replacement studs and nuts and a new donut for that pipe connection.
now the fun part. remove the 6 bolts that retain the manifold to the head. if you have all the stock ignition shielding. take some photos of those little brackets before you losen the bolts so you can get them back on correctly later.
lay all the bolts and spacers out in the correct order to make reassembly easier.
I DO recommend using good Quality gaskets. I prefer fel-pro. The factory didn't use gaskets. but it was new then. 40 plus years of heating and cooling tends to make things less than perfectly flat.
Hopefully all the bolts come out O.K. Good luck.
Exhaust manifolds are bolted to the heads. Not the block.
get under the car and undo the 3 nuts holding the pipe to the manifold. just pull the pipe down an inch or so, just enough to clear. now is a good time to get replacement studs and nuts and a new donut for that pipe connection.
now the fun part. remove the 6 bolts that retain the manifold to the head. if you have all the stock ignition shielding. take some photos of those little brackets before you losen the bolts so you can get them back on correctly later.
lay all the bolts and spacers out in the correct order to make reassembly easier.
I DO recommend using good Quality gaskets. I prefer fel-pro. The factory didn't use gaskets. but it was new then. 40 plus years of heating and cooling tends to make things less than perfectly flat.
Hopefully all the bolts come out O.K. Good luck.
Thread Starter
Instructor
Joined: May 2019
Posts: 103
Likes: 13
From: Near D.C.
Thanks for the help. I was able to get the bolts out of the heads (not the block...oops). They appeared to be in there very tight so I don’t think that was the issue, but great point. I’ll get the studs out of the pipe soon and and replace as recommended above. Appreciate all the help! You guys are great.
If anyone else has ideas, I’m all ears. I’ll hopefully tackle this at some point over the weekend.
If anyone else has ideas, I’m all ears. I’ll hopefully tackle this at some point over the weekend.
Drifting
Joined: Oct 2006
Posts: 1,875
Likes: 779
From: Persona Non Grata
2022 C3 of the Year Finalist - Unmodified
I suggest studs with a hex end. Makes getting them secure easier. Two on my car weren't. One was lost, one was loose. Guess which ones. Willcox has them, and Ernie is the best!
Race Director
Joined: Nov 2006
Posts: 13,195
Likes: 7,795
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
you can pick up the studs with long brass nuts in most every auto parts store. Dorman make a bubble pack kit. also exhaust gaskets and manifold donuts are readily available for gen 1 small block Chev. no real need to pay shipping and wait.
Team Owner
Joined: Feb 2003
Posts: 54,062
Likes: 9,396
From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
GM never used exhaust manifold gaskets with iron heads. and there is no reason too if both surfaces are flat and true. so if the manifold is not flat take it to a machine shop and have it trued up.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Are the manifold retaining bolts the proper length [at each location]? If a bolt is slightly too long, the bolt will bottom out and the joint will not be tight. Also, there is a lot of heat-cycling and vibration going into those manifold bolts. The MUST be retained securely or leakage may occur. Use French locks (as used by factory on SBC engines) or lock-wire to firmly hold bolts in place so torque cannot be lost.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski