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#1 |
Registered User
Join Date: Apr 2012
Location: Ferndale, CA
Posts: 6
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Exhaust manifold gasket keeps burning up
71 C20 with a 350 that looks stock. The driver's side exhaust manifold was leaking so I replaced the gasket. Less than 100 miles later it started leaking again. I pulled it off and it burnt through the cork on the 2 center ports. Do I need to have the manifold machined/replaced?
Last edited by jltonline; 05-07-2012 at 11:34 PM. Reason: Clarification |
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#2 |
Quit if it's not FUN!!!
Join Date: Jul 2010
Location: Indian Trail, N.C,
Posts: 864
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Re: Exhaust manifold gasket keeps burning up
FIRST! Welcome to the Board,
![]() Now, most stock manifolds don't really need the gaskets, unless it's severally warped, which I doubt. Clean the manifold and port surfaces with a Scotchbrite pad and bolt it on without a gasket. Bet it won't leak, at least worth a try.
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MY MOTTO: Eat it all up, Wear it out, Use the last few drops, Spend all you've got, Late in life, you'll think of the things you didn't do, not the things you did. - Get out and experience life ! . Robbie Robinson a.k.a. TobyArnot (Toe Bee or not toe bee) ![]() |
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#3 | |
Registered User
Join Date: Feb 2000
Location: Center City, MN, USA
Posts: 3,253
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Re: Exhaust manifold gasket keeps burning up
Quote:
I have NEVER used a gasket between a factory head and a factory exhaust manifold.
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#4 |
Registered User
Join Date: Apr 2012
Location: Ferndale, CA
Posts: 6
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Re: Exhaust manifold gasket keeps burning up
Thanks for the welcome. Here are a couple pics. This is on the center ports. I torqued the outer bolts to 17ft-lbs and the center bolts to 27ft-lbs per Chilton's manual. I will clean it and bolt it together without the gaskets to see if it makes a difference.
![]() This is the metallic side that still looks good. ![]() This is the cork material that has already burned away.
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71 C-20 |
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#5 |
Active Member
![]() Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
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Re: Exhaust manifold gasket keeps burning up
Check to make sure that the manifold is completely flat as mentioned above. If you're not sure have them machined. I've gone the gasket and no gasket route and haven't had any problems either way, however, just a slight deviation from completely flat will eventually burn the gasket if you use one.
If you use a gasket, install the gasket with the steel face toward the manifold and the fiber surface against the head. (Federal Mogul site) |
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#6 |
425hp409
![]() Join Date: Oct 2008
Location: Prosper Texas
Posts: 841
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Re: Exhaust manifold gasket keeps burning up
I have never used gaskets as that is the way Chevrolet built the trucks. The gaskets are to make up for any small deviation in the flatness of the manifold. make sure that when you have the manifold off of the truck that you take a flat file and file the surface of the manifold and the head and you will not have any other problems.
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#7 |
Registered User
Join Date: Jan 2011
Location: Paragould Ar.
Posts: 41
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Re: Exhaust manifold gasket keeps burning up
I have built 2 motors 1 I used Patroit headers with the gaskets you showed in your pics. And they never leaked The other I used Headman headers and the best gaskets you can get and them suckers leak no matted what I do!!!!
Buz 48 |
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#8 |
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Join Date: Jul 2011
Location: strausstown pa
Posts: 3,394
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Re: Exhaust manifold gasket keeps burning up
headers or manifolds they are the gaskets too use Ive had very few issues with them.
there has to be a irregular suface either on the head or the manifold
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#9 |
Senior Member
Join Date: Jul 2001
Location: Muskegon,MI,USA
Posts: 6,026
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Re: Exhaust manifold gasket keeps burning up
Have you been putting the gaskets on with the metal facing the manifold? The manifolds get hotter then the heads so it is better to have the metal toward them.
Jim
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#10 |
Registered User
Join Date: Apr 2012
Location: Ferndale, CA
Posts: 6
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Re: Exhaust manifold gasket keeps burning up
I put them on with the metal facing the heads. I assumed they would get hotter. I am going to pull the manifold off and take it to a friend who has a machine shop.
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#11 | |
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Location: Centrally located between Houston, Austin and Waco. BCS area.
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Re: Exhaust manifold gasket keeps burning up
Quote:
btw: the material is a heat resistant material and not cork which wouldn't last very long at all. |
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#12 |
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Join Date: Apr 2012
Location: Ferndale, CA
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Re: Exhaust manifold gasket keeps burning up
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#13 |
Cruzin
Join Date: Dec 2009
Location: on the road
Posts: 2,835
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Re: Exhaust manifold gasket keeps burning up
i never run gaskets on maniflolds, no problems
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#14 |
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Location: Foster Rhode Island
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Re: Exhaust manifold gasket keeps burning up
I always use a large flat file and hold it from the two ends and go side ways over the surface of the stock manifold till is all flat and shiny every where it will contact the head. An older ''Chevy guy'' showed me that around 25 or 30 years ago. No gaskets no problem ever. Seems to work much much better than if you tryed to use the file the long way. It needs to be a good sharp file.
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#15 |
Registered User
Join Date: Jul 2011
Location: strausstown pa
Posts: 3,394
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Re: Exhaust manifold gasket keeps burning up
the sealing surface looks pretty rough If you have a way to keep it extremly flat you could very lightly hit it with a belt/disc sander then finish it with a file but it must be flat and level.
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81 camaro 355 4/spd 342 posi my first love ![]() 67 swb step 454/4spd ott 373 posi 4/7 drop. 2000 s10 zr2 little blue truck that never gets stuck. '74 heald super bronc vt8. tecumseh powered moon rover. |
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#16 |
Registered User
Join Date: Jan 2011
Location: Chattanooga, TN
Posts: 2,144
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Re: Exhaust manifold gasket keeps burning up
It almost looks like the port on the left in the photo is not flat at all. May just be the photo. I would clean it up and use a long straightedge to check it.
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#17 |
Active Member
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Re: Exhaust manifold gasket keeps burning up
Yeah, I agree with above. Looks rough. Machine shop shouldn't charget that much to level it off for you if they have the proper equipment.
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#18 |
Chemist under the hood...
Join Date: Apr 2009
Location: Fort Erie,ON, Canada
Posts: 617
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Re: Exhaust manifold gasket keeps burning up
X2 I just did my ramshorn too. No leaks, no gasket issue.
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#19 |
Registered User
Join Date: Apr 2012
Location: Ferndale, CA
Posts: 6
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Re: Exhaust manifold gasket keeps burning up
Picked it up from the machine shop this afternoon. You can see where it was messed up. Put it on without a gasket and seems fine so far. Thanks to everyone for your advice/thoughts/suggestions.
![]() Now I just need to fine tune the carb and maybe I can make this my daily driver.
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71 C-20 |
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#20 | |
Chemist under the hood...
Join Date: Apr 2009
Location: Fort Erie,ON, Canada
Posts: 617
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Re: Exhaust manifold gasket keeps burning up
Quote:
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Current fleet: 2013 GMC Sierra, 5.3L, 4x4 1988 GMC Sierra, 305, Auto 1984 Jeep Grand Wagoneer, 360 V8 1997 VW Cabrio, 2.0L 2017 Toyota Rav4, 2.5L Stuff I wish I still had: 2013 Toyota Matrix [RIP] 1967 GMC 910 Fleetside, 283 V8 [1st Love-SOLD] 1987 Jeep Cherokee Laredo 4X4, 4.0 I-6 [SOLD} 1994 Chevrolet Caprice Classic, 5.7LV8 [SOLD] 1995 Chevrolet Astro AWD, 4.3L V6 (RIP) 1998 Chevrolet Suburban 4x4, 5.7L V8 [SOLD] |
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#21 |
Registered User
Join Date: Nov 2011
Location: White Cottage, Oh.
Posts: 99
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Re: Exhaust manifold gasket keeps burning up
Glad to see you got it fixed, but another old school trick is to use two sets of gaskets, doubling them up. Be sure to re-torque the bolts after a few heating/ cooling cycles, and torque from the center out...
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#22 |
Registered User
Join Date: Apr 2012
Location: Ferndale, CA
Posts: 6
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Re: Exhaust manifold gasket keeps burning up
That was my original plan when I heard it start leaking again but it burnt through the gasket before I got it home.
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