Exhaust Manifold Gasket

8N Ren · Jan 10, 2014

Howdy all!

I replaced my gasket last year around the end of March or so. Just recently while my points were in the middle of retiring the tractor popped/backfired. Changed the points and all is well, or so I thought. Now I noticed the other day that I have an exhaust leak at the #4 port.

My question is, when you get a backfire/popping etc can/will that ruin the exhaust manifold gasket?

Regardless I'm replacing it anyways, just curious.

Bruce (VA) · Jan 10, 2014

"My question is, when you get a backfire/popping etc can/will that ruin the exhaust manifold gasket?"

No.

Sometimes the leak isn’t from the gasket.It’s because the manifold or block is damaged. Look for smoke tracks. If the block is badly pitted, (usually around # 4) you will have problems; get out the hi-temp metal epoxy. (Not JB Weld) VersaChem's exhaust manifold repair, or ThermoSteel, is said to be good to 2000 degrees. Clean the area real well with brake cleaner, put a little epoxy on it, put some wax paper over it and bolt down the manifold. After it dries take off the manifold and take a die grinder and clean the epoxy that might squish into the port. Look at the manifold, again around # 4. If it’s pitted & burned, it isn’t going to seal. Time to surface it or get a new one. Do not double the gaskets! The gasket has two pieces, left & right (or front & back.....whatever) Use hi-temp Permatex or even Copper coat. Make sure the surface is squeaky clean!

If it's the manifold, it's usually cheaper to replace it instead of getting it surfaced.

75 Tips

old · Jan 10, 2014

Could it back firing blow out the gasket well that is a sort of yes/no thing. If as Bruce shows you, you have a rough/bad area in the manifold yes it could have blown it out but it would already have been going out it just did it faster

8N Ren · Jan 10, 2014

Last year when I replaced the old gaskets, my manifold was no where near as bad as the one in Bruce's photo. When I replace them again I'll take a better look this time and post back with pictures. Thanks guys! Have a nice weekend.

old · Jan 10, 2014

Be sure to check the block also for rough areas and also check the manifold being flat

notjustair · Jan 10, 2014

It would be rare with a fixed throttle engine like a tractor. I have had a Ford 429 pop hard enough to blow a manifold apart and blow out the exhaust gasket. It was quite an experience. It was a cold blooded engine and happened when the throttle wasn't feathered enough. Like a say, something where you aren't using a foot feed usually doesn't backfire very hard. Not a fast rule, but just what I have seen on everything I've encountered.

Brian 2N Iowa · Jan 10, 2014

8N Ren - My manifold and engine block is pitted in a C shape (to outside) on Cyl# 1 & 4. I have found I need to replace the gasket every couple of years due to blow-out.

Thanks Bruce I will have to try the epoxy next time!

If I can get on my soap box...My 13 Yr old Daughter assisted me this fall with the installation on my N. It amazes me when she has the intelligence to comprehend the physics, Geometry and application reasoning to make the tractor work. I am taking advantage of the priceless father/daughter bonding time.

8N Ren · Jan 13, 2014

So this is what it all looks like. I went ahead and replaced the gasket but I'm ordering a new manifold that I will replace when to snow goes away and the temps warm up.

I seem to be having troubles with pics today.

Exhaust Manifold Gasket

8N Ren

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Bruce (VA)

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old

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8N Ren

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old

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notjustair

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Brian 2N Iowa

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8N Ren

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