exhaust manafold question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

griesel72 · 03-21-2004, 08:47 PM

I just swapped out my single stock exhaust for a dual setup i got off another truck. I took my time and put it on right, but now there is a bad leak right around the manafolds where they meet the exhaust. Is there a gasket of some kind of forgot, or is there a trick that i didn't know about. Any help would be appreciated, i'm really wondering what is going on here.

thanks
David

JimKshortstep4x4 · 03-21-2004, 08:53 PM

The exhaust manifolds that were set up with heat risers did not have an internal chamfer on them and the exhaust doughnuts will not seat very well against a flat surface. I am not sure if this is the situation that you have, but it is all that I can think of based on your description.

Jim

griesel72 · 03-22-2004, 01:15 AM

Yeah, they are set up with heat risers, should i try red silicone, or is there something else?

Thanks
David

68speedalert · 03-23-2004, 02:47 AM

Speaking of heat risers, is your truck set up the same as the one you took it off of? 67-68s had the riser on the left side, 69-70s had it on the right side, and 72 didn't use on at all. If your's isn't the same, it could be putting the pipe at a different anlge and not be able to seal.

Steve

griesel72 · 03-23-2004, 11:21 AM

The truck i put the exhaust on is a 69, the truck i took the exhaust off of is a 70, but i think it had a later model 350 in it. You might be on to something there, thanks 68 speedalert

Dean · 03-23-2004, 12:08 PM

This is what the bottom of one with a heat riser looks like

Dean · 03-23-2004, 12:09 PM

This is the heat riser and the gasket that goes between them.

Dean · 03-23-2004, 12:10 PM

On the other side of the heat riser you should have a little piece of pipe with the donut around it. A lot of people don't remember that little piece of pipe and the donut will blow out in time. GM used this little piece from the factory.

68speedalert · 03-23-2004, 01:39 PM

Good posts Dean!

Steve

03-21-2004, 08:47 PM	#1
griesel72 Senior Member Join Date: Apr 2003 Location: Howard, Kansas USA Posts: 1,997	exhaust manafold question I just swapped out my single stock exhaust for a dual setup i got off another truck. I took my time and put it on right, but now there is a bad leak right around the manafolds where they meet the exhaust. Is there a gasket of some kind of forgot, or is there a trick that i didn't know about. Any help would be appreciated, i'm really wondering what is going on here. thanks David __________________ 1969 K10 Custom 10 1997 Z71 2006 Volkswagen Jetta TDI 2006 King Ranch 1980 Wife

03-22-2004, 01:15 AM	#3
griesel72 Senior Member Join Date: Apr 2003 Location: Howard, Kansas USA Posts: 1,997	Yeah, they are set up with heat risers, should i try red silicone, or is there something else? Thanks David __________________ 1969 K10 Custom 10 1997 Z71 2006 Volkswagen Jetta TDI 2006 King Ranch 1980 Wife

03-23-2004, 02:47 AM	#4
68speedalert Semi-Senior Member Join Date: Feb 2003 Location: Washington, MO Posts: 390	Speaking of heat risers, is your truck set up the same as the one you took it off of? 67-68s had the riser on the left side, 69-70s had it on the right side, and 72 didn't use on at all. If your's isn't the same, it could be putting the pipe at a different anlge and not be able to seal. Steve __________________ '68 50th Anniversery LWB Custom Fleetside, '77 305 v-8, turbo 350, factory speed alert (still works), '71 drivetrain w/front discs. Some call it ugly yellow, others call it Ochre '83 Jeep CJ-7, <80,000 miles, original owner '04 Chevy Suburban, 4x4, 2500, 6.0 ltr, Predator Diablo programmer '95 GMC K1500 Extended cab

03-23-2004, 11:21 AM	#5
griesel72 Senior Member Join Date: Apr 2003 Location: Howard, Kansas USA Posts: 1,997	The truck i put the exhaust on is a 69, the truck i took the exhaust off of is a 70, but i think it had a later model 350 in it. You might be on to something there, thanks 68 speedalert __________________ 1969 K10 Custom 10 1997 Z71 2006 Volkswagen Jetta TDI 2006 King Ranch 1980 Wife

03-23-2004, 12:08 PM	#6
Dean Senior Member Join Date: Jan 2000 Location: Cincinnati, Ohio Posts: 1,492	This is what the bottom of one with a heat riser looks like Attached Images

03-21-2004, 08:53 PM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	The exhaust manifolds that were set up with heat risers did not have an internal chamfer on them and the exhaust doughnuts will not seat very well against a flat surface. I am not sure if this is the situation that you have, but it is all that I can think of based on your description. Jim

03-23-2004, 12:09 PM	#7
Dean Senior Member Join Date: Jan 2000 Location: Cincinnati, Ohio Posts: 1,492	This is the heat riser and the gasket that goes between them. Attached Images

03-23-2004, 12:10 PM	#8
Dean Senior Member Join Date: Jan 2000 Location: Cincinnati, Ohio Posts: 1,492	On the other side of the heat riser you should have a little piece of pipe with the donut around it. A lot of people don't remember that little piece of pipe and the donut will blow out in time. GM used this little piece from the factory.

03-23-2004, 01:39 PM	#9
68speedalert Semi-Senior Member Join Date: Feb 2003 Location: Washington, MO Posts: 390	Good posts Dean! Steve __________________ '68 50th Anniversery LWB Custom Fleetside, '77 305 v-8, turbo 350, factory speed alert (still works), '71 drivetrain w/front discs. Some call it ugly yellow, others call it Ochre '83 Jeep CJ-7, <80,000 miles, original owner '04 Chevy Suburban, 4x4, 2500, 6.0 ltr, Predator Diablo programmer '95 GMC K1500 Extended cab



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