Gasket or not?
Thread Starter
Racer
Joined: Jul 2002
Posts: 264
Likes: 0
From: Franklin Ohio
Gasket or not?
78, L48 orginal exhaust manifolds. On the passengers side where the heat riser valve connects to the manifold. There was not one on when I removed the old pipes and I don't see one in the AIM but metal to metal just does not seem right. The vendors carry a gasket for this but only up to and including 1973. Should I just get one of those or will there not be a problem going without.
Thanks!
Thanks!
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
I've read that a lot of cars have the exhaust manifold milled so well during assembly that exhaust gaskets weren't originally needed. Maybe it was the same with that gasket - if it is smooth and clean enough, it probably doesn't need one... 
Drifting
Joined: Apr 2003
Posts: 1,323
Likes: 2
From: Castle Hills Texas
Well, that is exactly where I had an exhaust leak. I had a gasket put there and it fixed me up. I have heard that story about the gaskets not being needed. While in theory, it seemed to work for a while, I have never had a car where I chased down so many exhaust leaks. That has been my experience with the gasketless Vette.
Thread Starter
Racer
Joined: Jul 2002
Posts: 264
Likes: 0
From: Franklin Ohio
I don't think I explained this very well. On the passengers side between the bottom of the manifold and the exhaust pipe is a flapper valve. The connection between the top of that valve and the bottom of the manifold is my concern. Those two surfaces are basicly flat. The bottom of the valve and the exhaust pipe has a donut type gasket. This is not about the manifold to the head gasket.
Drifting
Joined: Apr 2003
Posts: 1,323
Likes: 2
From: Castle Hills Texas
No, you explained it well. That was the very first place I had a leak, down by the heat riser. I don't believe that there was a gasket there when I had my leak fixed. They put in a doughnut gasket and all is well. Wheather there was supposed to be one there originally, I couldn't tell you.
Last edited by CVT4ME; Sep 24, 2004 at 04:34 PM.
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Instructor
Joined: Aug 2004
Posts: 139
Likes: 0
From: Austin Tx
Guys I'm going to hijack in on this one, it looks like it is about over anyway. Last week I tried to remove this Y pipe to drop the oil pan. Well the kid here was unable to do it. I couldn't get the right side pipe down below the studs on the ex. manifold to pull it forward out of the next exhaust pipe piece. I cut the damn thing with a cut saw and did the oil pan. Welded it back togeather, ground off the weld, it looks ok, but is their a trick that I don't know to get the Y out in one piece.
Thread Starter
Racer
Joined: Jul 2002
Posts: 264
Likes: 0
From: Franklin Ohio
Hey kid, I understand about cutting something when doing the exhaust pipes! I hit one of the transmission lines when cutting mine. Lucky for me a compression fitting took care of that and I didn't have to go thru the beating of removing the line. About you Y pipe, not sure here since mine was already gone. Milo is right, they didn't come with a gasket but what I did find out is that on a '73 they used a gasket between the bottom of the manifold and the top of the heat riser. I bought one at Auto Zone for .89 and it worked like a charm! Now with that and the doughnut between at the pipe I didn't have any leaks!