Head gaskets
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Stellar HDF Member
Joined: Jan 2015
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From: ct
Head gaskets
So stock gasket is .060" not .045" like I was told. So should I go with the .045" that comes in the kit or the .030" that I WAS considering ? Or buy .060" separately.?????
Dirt don't hurt
Joined: Jan 2011
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From: Haslet Texas
I'd always heard 45thou myself...
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Stellar HDF Member
Joined: Jan 2015
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From: ct
Old gasket had a 60 stamped on it and part number, I measure it and over .050".
Googled Oem# and there it was (16773-85)=.060"
Curious because kits offer 30 & 45 so was surprised to see the 60 thousand.
Googled Oem# and there it was (16773-85)=.060"
Curious because kits offer 30 & 45 so was surprised to see the 60 thousand.
Road Captain
Joined: Apr 2015
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From: NorCal
What was your reason for considering the .030 over the .045? I understand it would change the compression but how much? Would it really make a noticeable difference? In the process of a rebuild and curious.
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Stellar HDF Member
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From: ct
Not sure how much you would notice but given the choice to increase compression slightly to compliment the cam upgrade and might as well do it while I'm there,. Just not sure if I want to go from a 60 to a 30 or 60 to a 45. The .060" gasket thru me off a bit.
Club Member
Joined: Aug 2008
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From: Lafayette, Louisiana
Take measurements otherwise you will ask yourself so many times in the future that you will have to open it up again to prevent insanity
I took .025" off my heads and also went with the .030" head gasket.
Another factor is the thickness of the base gasket.
Take the measurements then decide
Evo's respond well to compression increases as long as clearance is adequate
I took .025" off my heads and also went with the .030" head gasket.
Another factor is the thickness of the base gasket.
Take the measurements then decide
Evo's respond well to compression increases as long as clearance is adequate
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From: St. Louis, MO
For point of reference, because I have all the info to tell me this on my car, in my Vette going from a stock .057 gasket to .030 (with a 4" bore) raises compression from 10.9 to 11.4.
I found it to be a very worthwhile gain. That said, note that I am able to adjust timing very granularly for RPM and load in my car which you can't do on an Evo...and I have knock sensors to keep me safe if I get too aggressive...so not sure you'll be able to take full advantage. Even so, I'd do it. Compression tends to be your friend in a build allowing you to tame a bigger cam which I know you're wanting to do. Heck, as big a cam as you want to run you might want to mill the heads...though I don't know on an Evo where you have to start to worry about piston to valve issues, normally an advanced intake lobe with long duration will cause problems in PtV clearance.
Only potential downside is I think it'd be wise to run adjustable pushrods if you're going to use thinner gaskets, you might be causing too much preload in the lifters if you use stock pushrods.
I found it to be a very worthwhile gain. That said, note that I am able to adjust timing very granularly for RPM and load in my car which you can't do on an Evo...and I have knock sensors to keep me safe if I get too aggressive...so not sure you'll be able to take full advantage. Even so, I'd do it. Compression tends to be your friend in a build allowing you to tame a bigger cam which I know you're wanting to do. Heck, as big a cam as you want to run you might want to mill the heads...though I don't know on an Evo where you have to start to worry about piston to valve issues, normally an advanced intake lobe with long duration will cause problems in PtV clearance.
Only potential downside is I think it'd be wise to run adjustable pushrods if you're going to use thinner gaskets, you might be causing too much preload in the lifters if you use stock pushrods.
Last edited by Joe_G; Nov 15, 2015 at 07:04 PM.
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Thread Starter
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Stellar HDF Member
Joined: Jan 2015
Posts: 2,504
Likes: 150
From: ct
Take measurements otherwise you will ask yourself so many times in the future that you will have to open it up again to prevent insanity
I took .025" off my heads and also went with the .030" head gasket.
Another factor is the thickness of the base gasket.
Take the measurements then decide
Evo's respond well to compression increases as long as clearance is adequate
I took .025" off my heads and also went with the .030" head gasket.
Another factor is the thickness of the base gasket.
Take the measurements then decide
Evo's respond well to compression increases as long as clearance is adequate