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Felpro Mls with O-Ringed head

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1fastlaser

20+ Year Contributor
965
0
Jan 25, 2003
glendora, New_Jersey
I thought ive read it before but not sure if people have done it. I would guess I is no different then a oem mls and a o ring.
 
It would have to be a copper o-ring. I've never done it with an MLS gasket, so I can't offer any advice on how much protrustion to have or how long the copper will last. Should make for a tight setup if it's done right.

In any case, I'd always o-ring the block rather than the head if possible.
 
Copper rings with mls are useless. The copper just smashes down. As mentioned above, i always ring the block anyway.
Any time a protruding o-ring is used, something has to give. With a composite gasket and SS rings, the gasket gives. With an MLS gasket, the copper rings give. In either case, that doesn't mean sealing isn't improved. The copper o-ring/MLS combo has been sucessful for years. The only drawback is that you're replacing the o-rings everytime you pull the head.
 
I run a stainless o-ring in the head on a OEM MLS gasket per Shep's reccomendation years ago and have not pushed a single drop of coolant thus far up to 60psi of boost. In Jason's street car and the other cars here we run copper o-rings in the block with OEM MLS gaskets.
 
I would think a block with steel o-rings with a matching reciever grove in the head used with a copper head gasket would be the best solution.. In your case a composite gasket would be ideal for you. Thats my opinion
 
I ran a composite with the o ring for years. I know Alex at Dogbox runs oem mls with a Ss o ring in the head in all his builds. I pulled a motor apart with a Ss o ring in the head with a oem mls and the o ring does push into the gasket quite a bit. I guess I'll just compare the gasket to the oem mls with a o ring and with out since I got 2 used ones laying around.

FYI this is a G4CS block. Shooting for mid upper 600s on straight pump gas on this motor and sky's the limit on safe gas. Numbers don't mean to much but the track numbers is what I'm lookin for.
 
I learned the hard way boys a couple years ago I ran a copper o-ring block with a felpro 1153-1 MLS. Found out later after pushing coolant that the block o-rings pushed on the MLS built-in o-ring and ruined my head surface. Shep is actually who figured out what happened after I sent him the head to resurface and o-ring. Completely ruined a nice head!

DO NOT USE AN O-RING HEAD OR BLOCK WITH A FELPRO 1153-1 MLS
 
^^ Yep, DO NOT run Felpro MLS gasket with an o-ring'd head or block. Reason being, the Felpro has a built in o-ring that is 'D' shaped. If you run o-rings in the block or head you will overlap them into the gaskets o-ring which is a bad thing. Felpro MLS and L-19/A1 head studs is all you need.
 
I run an o-ringed block with stainless o-ring and cometic head gasket. 30 psi on my 40r for almost 2 yrs and 60+ passes. My machinist did say he dropped the o-ring a little deeper since I had an mls.
 
I run a stainless o-ring in the head on a OEM MLS gasket per Shep's reccomendation years ago and have not pushed a single drop of coolant thus far up to 60psi of boost. In Jason's street car and the other cars here we run copper o-rings in the block with OEM MLS gaskets.
Interesting. Do you know how far the o-ring is protruding from the surface?

I assume it would have to be a fair amount less than how they set it up for a composite gasket.
 
Finally a answer! Thank for the the post. Here is info learned. Looks like I'll have to do another head or have the head surfaced with the o rings in there to seal them up.
 
Never had a problem with a composite and the oring with standard arps. I'm running L19s with the new motor. It's hard to say I could easily run a composite but figured I'd try the felpro out. I'd hate to build this head and then wish I went another route. I wanna shoot a rod out of the block before a kill a gasket that's all I know
 
Well lifted a felpro mls. Going to a o ringed head. I har a factory 2.4 composite gasket, might pick up a oem mls and bore it to 87mm and test that out.
 
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