Head gasket reuse
Thread Starter
NCM Grand Opening Veteran
Joined: Sep 2005
Posts: 20,979
Likes: 384
From: South of giving a damn
St. Jude Donor '11, '17
Head gasket reuse
@Jebbysan @gkull
Well I've been having trouble with my engine starting. Got to the point where I went and got a bore scope to look in #1 to make sure the piston was actually up. Between the bore scope, the carbon soot, and my overactive imagination it looked like the piston was broken. So for lack of anything better to do I pulled the head and - wait for it - nothing was amiss. Since Ive torn it down this far I'm going to pull the time chain cover and verify the timing.
This is a SBC 396 with AFR 195 heads. I used Cometic Copper head gaskets when I built it. This engine only has a few hours runtime on it so can I reuse the Cometics? Saves pulling the other head.
Well I've been having trouble with my engine starting. Got to the point where I went and got a bore scope to look in #1 to make sure the piston was actually up. Between the bore scope, the carbon soot, and my overactive imagination it looked like the piston was broken. So for lack of anything better to do I pulled the head and - wait for it - nothing was amiss. Since Ive torn it down this far I'm going to pull the time chain cover and verify the timing.
This is a SBC 396 with AFR 195 heads. I used Cometic Copper head gaskets when I built it. This engine only has a few hours runtime on it so can I reuse the Cometics? Saves pulling the other head.
Last edited by ratflinger; Dec 6, 2023 at 01:16 PM.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
You can reuse most any head gasket as long as it pulled away clean......but me being me, if I reuse a head gasket I always use Permatex Copper Spray a Gasket......
Recently I reused some Fel-Pro steel shim gaskets.....the coating they use rubbed off so I just wiped it all down with thinner and used the Copper Spray.......I also reused a $100 Cometic Graphite head gasket for a 1980 Honda CBX 6 cylinder.....and yes, sprayed it when reinstalling it......
Now here is the rub......the first engine was not fired, the Honda was run til hot and shut off.......the Honda gasket pulled free like new, if anything transfers from the gasket to the deck...toss it.
Copper gaskets I believe from Cometic have those sealing ribbons printed on them.......you will have to use some thin RTV....VERY THIN......around each water hole on both sides......this is how they were installed before the ribbons existed.....they were just a hunk of cookie cut copper......
Hang the gasket from wire and spray both sides evenly......I put two coats on and let it sit 10-15 minutes @ 70 degrees then install.......seals every damn time......
Jebby
Recently I reused some Fel-Pro steel shim gaskets.....the coating they use rubbed off so I just wiped it all down with thinner and used the Copper Spray.......I also reused a $100 Cometic Graphite head gasket for a 1980 Honda CBX 6 cylinder.....and yes, sprayed it when reinstalling it......
Now here is the rub......the first engine was not fired, the Honda was run til hot and shut off.......the Honda gasket pulled free like new, if anything transfers from the gasket to the deck...toss it.
Copper gaskets I believe from Cometic have those sealing ribbons printed on them.......you will have to use some thin RTV....VERY THIN......around each water hole on both sides......this is how they were installed before the ribbons existed.....they were just a hunk of cookie cut copper......
Hang the gasket from wire and spray both sides evenly......I put two coats on and let it sit 10-15 minutes @ 70 degrees then install.......seals every damn time......
Jebby
Thread Starter
NCM Grand Opening Veteran
Joined: Sep 2005
Posts: 20,979
Likes: 384
From: South of giving a damn
St. Jude Donor '11, '17
@Jebbysan
Thank you Jebby.
I see you really like the Mahle 5746, but can I use this on 4.030 bore? If not do you have another suggestion? Do you use the Permatex on new gaskets also?
Thank you Jebby.
I see you really like the Mahle 5746, but can I use this on 4.030 bore? If not do you have another suggestion? Do you use the Permatex on new gaskets also?
Last edited by ratflinger; Dec 6, 2023 at 09:21 PM.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
@Jebbysan
Thank you Jebby.
I see you really like the Mahle 5746, but can I use this on 4.030 bore? If not do you have another suggestion? Do you use the Permatex on new gaskets also?
Thank you Jebby.
I see you really like the Mahle 5746, but can I use this on 4.030 bore? If not do you have another suggestion? Do you use the Permatex on new gaskets also?
I need something other than the old .039/.041 thick Fel Pro......which I use now only for zero deck assemblies......
I have two engines out there right now one with the 5746 and one with the 1134G and both are fine.......remember it is more about the prep and torque than it is about the head gasket as a part.......
I do not Copper Spray a brand new Graphite or Composite gasket......but steel shim I do......
Jebby
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I would NOT use copper head gaskets for a street machine. Very prone to failure unless you have an O-ringed block. Any preignition or detonation and the copper is gone. I used copper on my original solid roller 383 because it was thinner to get the perfect quench height. My DCR was too high for California 91 octane at sea level out on the road racing track. The fix was more duration cam to knock the DCR down
I use the Cometic MLS .027 compressed and it's very reusable if you don't damage it on removal.
I use the Cometic MLS .027 compressed and it's very reusable if you don't damage it on removal.
Race Director
Joined: Mar 2017
Posts: 11,931
Likes: 4,497
From: Virginia
I would NOT use copper head gaskets for a street machine. Very prone to failure unless you have an O-ringed block. Any preignition or detonation and the copper is gone. I used copper on my original solid roller 383 because it was thinner to get the perfect quench height. My DCR was too high for California 91 octane at sea level out on the road racing track. The fix was more duration cam to knock the DCR down
I use the Cometic MLS .027 compressed and it's very reusable if you don't damage it on removal.
I use the Cometic MLS .027 compressed and it's very reusable if you don't damage it on removal.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
copper spray like Jebby said is for steel shim type head gaskets and I have not used it in years. When you build stuff with lots of goop it makes them difficult to get apart. I hate mucking with heads that are stuck on the block. Always worried about damaging them during removal when you have a crow bar down the intake or a fine chisel to pry the head off.
I have aluminum heads and that's where Multi Layered Steel gaskets work the best. The higher cost outweighs future problems. Just stay away from copper gaskets it's a racing idea on engines that get repaired all the time.
I have aluminum heads and that's where Multi Layered Steel gaskets work the best. The higher cost outweighs future problems. Just stay away from copper gaskets it's a racing idea on engines that get repaired all the time.
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Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
I would NOT use copper head gaskets for a street machine. Very prone to failure unless you have an O-ringed block. Any preignition or detonation and the copper is gone. I used copper on my original solid roller 383 because it was thinner to get the perfect quench height. My DCR was too high for California 91 octane at sea level out on the road racing track. The fix was more duration cam to knock the DCR down
I use the Cometic MLS .027 compressed and it's very reusable if you don't damage it on removal.
I use the Cometic MLS .027 compressed and it's very reusable if you don't damage it on removal.
Not the best choice...Jebby