3rdCoastPowerSports

iTrader: (5)

anyone know the tolerances for flatness/ evenness of a cylinder head using an MLS gasket? Off the top of my head i think the absolute max is .003" but i could be wrong. any one know?

3rdCoastPowerSports

iTrader: (5)

just got off the phone with felpro tech line. if anyone wanted to know the answer to the question its is as follows (per felpro tech line rep):

Front--------------------Rear
allowed .001" per combustion chamber, so 4 chambers per head= .004" max tollerance

Up
|
| max tolerance is .001"
down

these are the absolute max tolerances. from experience i have run a .003" front to back tolerance (head was a little warped) and the head sealed up fine, not sure i would ever go past that though

ssnovaturbo

iTrader: (19)

If boosted, better make sure both head and deck surfaces are straight as an arrow....anything over 10lbs and it becomes a must

Jarren_b

Sorry to bump an old thread but was anyone able to confirm that the max tolerance for an LS2 block and head using an MLS gasket?

Im trying to measure mine

vettenuts

iTrader: (4)

Blocks are basically the same so the same numbers should apply. As I recall, there is a second number side to side but I can't remember the value. Thought it was 0.001" but am not positive about that.

RonSSNova

iTrader: (3)

Surface finish is also important. Modern mls gaskets need a smooth finish.
I found that out the hard way after having my heads cut in old school machinery.

I think .002" or less for heads. I was at .003" and had issues.

Jarren_b

GM says the max is .004.

How do you get a good finish? someone suggested I use 400 grit paper and WD40. is this correct?