Head gaskets
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Joined: Nov 2013
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Head gaskets
So I got the top end all done. Thanks to those who input on valve lash adjustment, pretty sure I nailed that cause it ran awesome on that aspect. But like most of us has been thru, if ain't one thing it's another. When I ordered my gaskets I went with Felpro 7733sp, it's the solid copper shim gasket that measures. 020. Unfortunately that gasket failed. I put 2 coats of the copper coat spray but after I pulled the heads tonight it looks like it failed at the bolt hole. Seems the hole in the gasket was a little off compared to the block, Idk how I didn't catch it when I mocked the gaskets up.
So the ones I'm looking at now are the Felpro 1094's, so I can get my quench still in the target range. I've also thought of just putting the standard. 041 gaskets to account for any imperfections in the block.
With the shim gaskets my cr is 9.5:1 with the standard ones it'd be 9:1 but the quench would be 066. With the stock dish pistons does quench really matter? It's a 75 l48 so the dish pistons aren't the best to begin with
So the ones I'm looking at now are the Felpro 1094's, so I can get my quench still in the target range. I've also thought of just putting the standard. 041 gaskets to account for any imperfections in the block.
With the shim gaskets my cr is 9.5:1 with the standard ones it'd be 9:1 but the quench would be 066. With the stock dish pistons does quench really matter? It's a 75 l48 so the dish pistons aren't the best to begin with
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
The head gaskets are not symmetrical, so they must be installed (oriented) properly on the block. That might be why yours appeared to have misalignment of holes.
Also, I have no idea why you would spray anything on a head gasket before installation. I thought that all Fel-Pro head gaskets should be installed 'dry'. Read the Fel-Pro installation instructions carefully and don't put anything on them unless required by those instructions.
Good luck with the next install.
Also, I have no idea why you would spray anything on a head gasket before installation. I thought that all Fel-Pro head gaskets should be installed 'dry'. Read the Fel-Pro installation instructions carefully and don't put anything on them unless required by those instructions.
Good luck with the next install.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,170
From: Hermosa
With the stock dish pistons does quench really matter? It's a 75 l48 so the dish pistons aren't the best to begin with
I used the felpro .015" head gasket and copper coat compound since my block did not have an appropriately smooth surface to mate to. 2000 trouble free miles with aluminum heads so far.
http://www.oreillyauto.com/site/c/de...2362&ppt=C1984
Double check the heads are flat as well as the block before you do it again. guessing you will but just in case.
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I went and the store order the 1094 's. I'm gonna meticulously clean the block and head surface again and check for straightness on both again. I didn't check the block before. I just assumed it was straight cause I didn't have issues previously. So that would be my own fault for assuming.
As for the gaskets not being symmetrical, they didn't have a left or right side stamp on them. So they have to be symmetrical
As for the gaskets not being symmetrical, they didn't have a left or right side stamp on them. So they have to be symmetrical
2026 Loser of the Year
Joined: Sep 2013
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From: New Or-leens Loo-z-anna
Practice............Practice............ .Practice!
Try using .025 thick gaskets.....the extra .005 could solve a slight head-bolt torque/warpage problem. I went from the stock .050 headgaskets to .025 on my iron-head SBC.....
I used the bolt tightening sequence.......15 lbs. the first go round......then I increased the torque the next go-round....3rd go-round I used the max recommended torque....took longer for each head---but no problems in two years
!noticeable improvement!
Try using .025 thick gaskets.....the extra .005 could solve a slight head-bolt torque/warpage problem. I went from the stock .050 headgaskets to .025 on my iron-head SBC.....
I used the bolt tightening sequence.......15 lbs. the first go round......then I increased the torque the next go-round....3rd go-round I used the max recommended torque....took longer for each head---but no problems in two years
!noticeable improvement!
Last edited by doorgunner; Dec 18, 2013 at 08:34 AM.
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Melting Slicks
Joined: Mar 2008
Posts: 2,666
Likes: 289
From: Spring Park MN
Did you lube the head bolts? If you don't lube the threads and the under side of the head on the bolts, you won't get accurate torque readings. I use Teflon paste on the threads and grease under the bolt head. The Teflon paste has a dual purpose. It will lube the threads and seal the bolts in the bolt holes.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
I would check other sources than Fel Pro for a thinner composite gasket. Trying to use a steel shim, copper or MLS gasket when surfaces aren't flat and machined surface finish isn't compatible is going to give you nothing but headaches. Mr Gasket has some thin graphite coated composite gaskets and I think Cometic might too. Perhaps consulting a local machine shop for parts/help in you situation. One reason why Fel Pros are 0.040" thick is to be able to conform to a imperfect surface. You may be fighting a losing battle hear in your search for proper quench, anything below 0.060" is pretty decent, going below 0.040" you better know what your doing and what your parts are made from and how much stretch they exhibit at high RPMs.
For torquing head bolts...Teflon sealer on threads and 30WT motor oil under heads just like Chevy did at original assembly.......
For torquing head bolts...Teflon sealer on threads and 30WT motor oil under heads just like Chevy did at original assembly.......