Using Rtv To Make A Gasket.

CarMichael Angelo

my rearend will smell so minty fresh,
15 Year Member
Nov 29, 1999
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Birmingham, al
Well that's what the tube says it is........"gasket maker".

I've never used any of the high temp silicones solely as the gasket between the intake and the head, as I've always been able to just buy the correct gasket from Felpro.
But Felpro doesn't make anything for a 4.0L crossflow head from Australia, and the stock gasket I have would need opening up to match the now bigger port.

Although I have a gasket, I only have one. It is the thickness of the cardboard backer that comes on a legal pad and again, I only have one. If for whatever reason, I need to take the intake off after installation, I'll be right back here, wondering if I can just forego the paper gasket, and go straight silicone.

I know that I'm gonna do that on the exhaust manifold flange, I'm going to use ultra copper there, as it has always been my practice on headers, but the intake is the reason for the question.

I'm putting that thing on for real today.
 
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Gasket maker - small ball peen hammer. Lay the gasket material out on what you need to gasket and tap gently around the edges & bolt holes using the ball end of the hammer...
The sharp machined edges of the part cut the gasket material. This works quite well as long as you figure some way to keep the gasket material from moving around while you are tapping away... Sometimes you lay the gasket material out and tap the bolt holes first. Then stick bolts in the holes that you just cut in the gasket.
 
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Make a template and send it to cometic, i did this with my header flanges and my intake gaskets. If i need a new set i just call them and within a week they ship it out to me. The gaskets are very afforable too. About 22 bucks for a pair of intake gaskets for my high ports.
 
I recently learned (the hard way) that high performance magnum Mopar builders will not utilize the front and rear seals on the intake due to leakage. Just like 350s, a thick bead front and back does it. (I'll let you know if the bead of high temp leaks (after setting the truck on fire).) I also "know a guy" who utilized a 72 hour dry time and a bead of high-temp to seal a water pump when the proper gasket could not be found in town. That guy will also let you know if it fails (after setting the truck on fire and pushing it down the hill). Actually, enough dry time and the right bead and it should hold against low boost levels between two true surfaces.
 
Gasket maker - small ball peen hammer. Lay the gasket material out on what you need to gasket and tap gently around the edges & bolt holes using the ball end of the hammer...
The sharp machined edges of the part cut the gasket material. This works quite well as long as you figure some way to keep the gasket material from moving around while you are tapping away... Sometimes you lay the gasket material out and tap the bolt holes first. Then stick bolts in the holes that you just cut in the gasket.
This is the method I was shown years ago.
 
I recently learned (the hard way) that high performance magnum Mopar builders will not utilize the front and rear seals on the intake due to leakage. Just like 350s, a thick bead front and back does it. (I'll let you know if the bead of high temp leaks (after setting the truck on fire).) I also "know a guy" who utilized a 72 hour dry time and a bead of high-temp to seal a water pump when the proper gasket could not be found in town. That guy will also let you know if it fails (after setting the truck on fire and pushing it down the hill). Actually, enough dry time and the right bead and it should hold against low boost levels between two true surfaces.

I never use those stupid rubber gaskets with the intake kit. I build a a big bead also, I am positive I never waited 72 hours though. Lol.
 
This is the method I was shown years ago.
Well, we have something else in common besides having worked on Mustangs and airplanes. I learned how to make gaskets with a ball peen hammer when I was a kid working on lawn mower engines for go-carts. That was over 55 years ago...