Intake gasket ??
Thread Starter
Racer
Joined: Jul 2011
Posts: 253
Likes: 4
Intake gasket ??
I find myself in need of changing intake gaskets, due to vacuum leak(327/350). I am going with the recommended Fel-pros. My question is, what is your opinion on using the supplied rubber end seals?
YouTube videos show them being tossed, in favor of running a bead of Hi-temp silicone across the valleys. Anyone with experience on this subject please chime in. Thank you!!
YouTube videos show them being tossed, in favor of running a bead of Hi-temp silicone across the valleys. Anyone with experience on this subject please chime in. Thank you!!
Burning Brakes
Joined: Jul 2014
Posts: 1,206
Likes: 378
From: Knoxville, TN
2020 C1 of the Year Finalist - Unmodified
end seals
I find myself in need of changing intake gaskets, due to vacuum leak(327/350). I am going with the recommended Fel-pros. My question is, what is your opinion on using the supplied rubber end seals?
YouTube videos show them being tossed, in favor of running a bead of Hi-temp silicone across the valleys. Anyone with experience on this subject please chime in. Thank you!!
YouTube videos show them being tossed, in favor of running a bead of Hi-temp silicone across the valleys. Anyone with experience on this subject please chime in. Thank you!!
Race Director
Joined: Apr 2015
Posts: 17,571
Likes: 3,461
From: Fresno California
On mine, the first time I did the intake gaskets, I used the rubber end seals. The second time I did them, which was a month later because they had failed, I used RTV alone, which was 3 years ago-- and is still leak free.
Burning Brakes
Joined: Nov 2001
Posts: 1,181
Likes: 313
From: St. Petersburg FL
I'd test fit the manifold first, with and without the seals--the fit may be affected by the way components were machined. If the end gaps are too small, that risks the seals getting deformed and squeezed out eventually. If the seals fit OK, I have generally used them though.
Race Director
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From: San Antonio, TX/Mahopac, NY
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Aluminum and iron expand and contract at different rates over every heat cycle. Over time, the cork or rubber seals have a higher probability of being pushed out. RTV also adjusts for a range of tolerances upon installation. The end seals were designed for use with iron manifolds, but you can use what ever logic you need to validate continuing to use them.
Racer
Joined: May 2003
Posts: 391
Likes: 36
From: taunton mass
end seals
I find myself in need of changing intake gaskets, due to vacuum leak(327/350). I am going with the recommended Fel-pros. My question is, what is your opinion on using the supplied rubber end seals?
YouTube videos show them being tossed, in favor of running a bead of Hi-temp silicone across the valleys. Anyone with experience on this subject please chime in. Thank you!!
YouTube videos show them being tossed, in favor of running a bead of Hi-temp silicone across the valleys. Anyone with experience on this subject please chime in. Thank you!!
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Race Director
Joined: Apr 2015
Posts: 17,571
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From: Fresno California
I have never used the end seals on dozens of Chevy and (shudder) Ford engines and I’ve never had a problem. A little smear around all four water ports and a 1/4” bead overlapping onto the gaskets for a worry free seal.
Aluminum and iron expand and contract at different rates over every heat cycle. Over time, the cork or rubber seals have a higher probability of being pushed out. RTV also adjusts for a range of tolerances upon installation. The end seals were designed for use with iron manifolds, but you can use what ever logic you need to validate continuing to use them.
Race Director
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From: northern california
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Le Mans Master
Joined: Feb 2008
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From: Folsom CA
I really like the Right Stuff also and it is tougher than Silicone.
On the China Walls I have always used Silicone with zero leaks. The only warning would be to check your gap with the manifold sitting on the block and make sure your bead of Silicone is thicker than that gap all the way across both ends.
A low spot will leak. If you set the manifold down by mistake and smear it you need to remove, clean and start over so you are sure the thickness is maintained.
All the Engine Builders I called on used Silicone.. It was quick, inexpensive and eliminated China Wall leaks. I find it much easier than using the Rubber or Cork China Wall gaskets.
On the China Walls I have always used Silicone with zero leaks. The only warning would be to check your gap with the manifold sitting on the block and make sure your bead of Silicone is thicker than that gap all the way across both ends.
A low spot will leak. If you set the manifold down by mistake and smear it you need to remove, clean and start over so you are sure the thickness is maintained.
All the Engine Builders I called on used Silicone.. It was quick, inexpensive and eliminated China Wall leaks. I find it much easier than using the Rubber or Cork China Wall gaskets.
Safety Car
Joined: Aug 2011
Posts: 3,578
Likes: 334
I really like the Right Stuff also and it is tougher than Silicone.
On the China Walls I have always used Silicone with zero leaks. The only warning would be to check your gap with the manifold sitting on the block and make sure your bead of Silicone is thicker than that gap all the way across both ends.
A low spot will leak. If you set the manifold down by mistake and smear it you need to remove, clean and start over so you are sure the thickness is maintained.
All the Engine Builders I called on used Silicone.. It was quick, inexpensive and eliminated China Wall leaks. I find it much easier than using the Rubber or Cork China Wall gaskets.
On the China Walls I have always used Silicone with zero leaks. The only warning would be to check your gap with the manifold sitting on the block and make sure your bead of Silicone is thicker than that gap all the way across both ends.
A low spot will leak. If you set the manifold down by mistake and smear it you need to remove, clean and start over so you are sure the thickness is maintained.
All the Engine Builders I called on used Silicone.. It was quick, inexpensive and eliminated China Wall leaks. I find it much easier than using the Rubber or Cork China Wall gaskets.
Team Owner
Joined: Aug 2007
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Army
Read this intake manifold article by JohnZ - I think it was written before the Right Stuff came out. You can use a 1-1/4" wooden dowel through the distributor hole to lay that intake straight down in place the first time. I did it and it worked like a champ... If you put a controlled bead of sealant on the Chinese walls then "squeeze out" shouldn't be a problem...
Last edited by Frankie the Fink; Aug 29, 2018 at 05:44 PM.
Le Mans Master
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Le Mans Master
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Perfect! Just finished Lifters in February.....The Right Stuff is great.....Consistent bead front and back.....steady intake manifold placement.....You will be happy.....
Last edited by dcamick; Aug 29, 2018 at 05:55 PM.
Instructor
Joined: Mar 2018
Posts: 181
Likes: 26
From: Bethlehem, PA
When I did it I could tell there was sufficient sealing material by the "squish" evident out the front and rear of the manifold. And once that stuff is cured it's not going anywhere.
Last edited by Chummy85623; Aug 29, 2018 at 06:13 PM.
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
That is probably the reason that wooden dowel was pictured in the GM Service Overhaul Manual decades ago. They recognized, even back then that some are too light in the shorts can lose foot traction when hoisting a cast iron manifold over the fender and the manifold will slip off location.
They could have suggested for these lightweights that they fill their back pockets with lead wheel weights to keep contact with the ground while installing the manifold. The wooden ***** is a good idea for some but not really necessary for most..
I always used the rubber in the end rails until I started reunning across aftermarket machined parts. Never had a problem with leaking until then. Maybe a little weeping, no leaking. Then one day I had a failure and I noticed there was not a sufficient gap on the end of the block to compress the rubber as designed. Not enough room. So, I went to the silicone and haven't gone back. The silicone does do a better, cleaner job if you don't apply too much of it.
Last edited by MikeM; Aug 29, 2018 at 06:50 PM.
Safety Car
Joined: Aug 2011
Posts: 3,578
Likes: 334
That is probably the reason that wooden dowel was pictured in the GM Service Overhaul Manual decades ago. They recognized, even back then that some are too light in the shorts can lose foot traction when hoisting a cast iron manifold over the fender and the manifold will slip off location.
They could have suggested for these lightweights that they fill their back pockets with lead wheel weights to keep contact with the ground while installing the manifold. The wooden ***** is a good idea for some but not really necessary for most..
I always used the rubber in the end rails until I started reunning across aftermarket machined parts. Never had a problem with leaking until then. Maybe a little weeping, no leaking. Then one day I had a failure and I noticed there was not a sufficient gap on the end of the block to compress the rubber as designed. Not enough room. So, I went to the silicone and haven't gone back. The silicone does do a better, cleaner job if you don't apply too much of it.
They could have suggested for these lightweights that they fill their back pockets with lead wheel weights to keep contact with the ground while installing the manifold. The wooden ***** is a good idea for some but not really necessary for most..
I always used the rubber in the end rails until I started reunning across aftermarket machined parts. Never had a problem with leaking until then. Maybe a little weeping, no leaking. Then one day I had a failure and I noticed there was not a sufficient gap on the end of the block to compress the rubber as designed. Not enough room. So, I went to the silicone and haven't gone back. The silicone does do a better, cleaner job if you don't apply too much of it.
Team Owner
Joined: Mar 2003
Posts: 26,118
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From: Greenville, Indiana
Burning Brakes
Joined: Feb 2000
Posts: 852
Likes: 113
From: Torrance California
Another trick is to dimple the china walls with a pin punch every 1/8" - 1/4". Along with the Right Stuff which I consider great stuff, this also minimizes any possibility of the sealant blowing out. Learned this years ago from a guy on the C4 forum.