Guys I have been having issues with my copper head gasket and stainless steel o rings sealing so I am going to a cometic mls gasket. I know they say not to run a MLS with o rings but I am after information from people that have done it and results as pulling out the engine and decking it is not an option.

I have heard high tech boosted import guys running 40+ psi are running there mls with o rings to seal them has anyone had experience?

If I was to run stainless steel o rings with a mls will it cut into it, maybe copper o rings with the steel gasket will work better?

Hopefully you guys have had experience??
Thanks

 

where are you ?
i wouldnt run a std MLS with a o ring...

 

the MLS deck / head surface has to be mint ! / good
they will not seal on anything alittle up and down

 

is this head a water jacketed head?

 

I am in Australia. Yest the head has water jackets both sides of the head and block, ie inline 6 cyl.

 

maybe the head is yeilding?
copper and o ring is way stronger
what size o ring?
how much protrustion on the o ring?
u anneal the copper gasket ?

 

I think those guys who you see running the MLS after the copper, take the SS o-ring out, and leave the groove.

 

You can run a MLS gasket like Cometec on s SBF if you remove the wire oring.

Keep the groove in the block, but remove everything from the groove. The MLS ring will sit in the groove, and work finr.

Not sure on your application though... Just giving you my experience... Bennett racing told me to run it like that and it worked.

 

+1. Look up RA, which is surface roughness. You'll need an RA of at least 30 or lower to seal a MLS gasket. I recently built a toyota 7M I6 and converted it to MLS, had a machine shop surface the head and block that said they could make it slick enough to seal with MLS, they failed. I had to manually sand the deck of both to get them smooth enough for it to seal. Hopefully you can find good machinist. Ask them what RA their machine can get, if they look at you funny or ask a question, walk away.

And also as mentioned, copper + o rings is stronger.

 

Do you have a groove in both the block and the head?

Typically higher boost engines like a dry deck configuration as you can seal the compression/combustion pressures but have a hard time with the water getting into the cylinders after shut-down.

A MLS gasket will work as well as a copper gasket but will also follow the head as it moves up and down.
Not that it matters when the deck surface is sealed. The key is getting the "combustion ring" (gas filled or otherwise) to follow the head.

A normal .062" gas ring WILL NOT have enough diameter to compress properly and still "follow the head"
when it lifts under high boost. A .093" gas ring WILL TYPICALLY have enough diameter to compress properly and still "follow the head" but sometimes there is not enough room to package the things with big bores and small bore center blocks. Copper when it compresses has very little memory and ability to follow the head.

Tom Vaught

 

I have family who run mls with the oring in place and they have the orings in both the block and head. they have made many runs at 48psi and no head sealing issues.

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I used to have a 732hp Honda Civic and what all of us big boost high horsepower cars would always O-ring the block and use the Cometic MLS gaskets. The thing is, you have to use copper wire instead of stainless wire in the O-ring groove. Stainless O-rings and a steel/stainless MLS gasket doesn't crush correctly. But when u have copper O-ring with a steel MLS gasket everything crushes correctly. I always ran copper wire O-rings with Cometic gaskets sprayed with a layer of gasket copper coat......using the described method sealed 37psi of boost and never leaked or seeped a drop of oil or coolant.

I too installed MLS gaskets with stainless O-rings and it blew the head gasket the first time we beat on it. After making the switch to copper wire I never had a single problem holding in over 30psi on a 1.8 liter 4 cylinder--Justin W.

 

It's not difficult to get the surface right, just takes a $20k machine