M20B32 86mm headgasket

[Schlander]

Hi Guys

I'm building a M20 stroker where I'm looking for the right headgasket. I can't find other than multilayer gasket that are extremely expensive.

What are your experiences? What can you recommend?

Daniel

[SkiFree]

You have found the joy of going with a larger bore piston.

Stock headgaskets work up to a +1mm overbore (85mm), anything larger and you are relegated to custom headgaskets. There are other material options like Copper, but they are not going to be any less expensive.

[downforce22]

I'm running ottoco brand, but looks like they don't make it any more. Vac sells one

https://store.vacmotorsports.com/vac-performance-mlsmulti-layered-steel-head-gasket-bmw-m20-p977.aspx

[digger]

MLS is probably the only real option, they work fine if the surfaces are prepped properly. dont buy from VAC they add a BS tax

[zaq123]

MLS is probably the only real option, they work fine if the surfaces are prepped properly. dont buy from VAC they add a BS tax

What he said. Ask you machinist what RA setting his machine can do for the surface finish. Cometic MLS requires 50 RA or finer finish

[digger]

Also there is an advantage with a MLS as you can get thicknesses in the following sizes which are around the stock sizes, 1.52, 1.73, 1.78, 1.91, 2.03, 2.18, 2.26 etc. others are available thicker and thinner to this means it is easier fine tune squish clearance…use a known shim measure clearance then order the size you need that gives the correct clearance

[zaq123]

Also there is an advantage with a MLS as you can get thicknesses in the following sizes which are around the stock sizes, 1.52, 1.73, 1.78, 1.91, 2.03, 2.18, 2.26 etc. others are available thicker and thinner to this means it is easier fine tune squish clearance…use a known shim measure clearance then order the size you need that gives the correct clearance

on the other note but on the subject:

my machinist thinks I'm weird for wanting to use OEM BMW head gasket for my stroker (85mm bore). Both the head and the deck are finished at 20 RA.
Anyway, I read a lot of people are unhappy with MLS on these I6, my primary reason for wanting to go OEM. Is it a valid concern or majority of builds are pretty successful with MLS? For 85mm bore where you can get away with OEM, would you still go MLS even if OEM std. or plus size could work or OEM is preferred choice (no boost)?

[digger]

ideally i would use an OE gasket wherever it possible/practical. i know people who have reused them after pulling the head though so it can be executed well.

isnt the s54 similar to a MLS?

[zaq123]

I always wondered about these Athena gaskets. Anyone with boost tried them?

[digger]

boosted e36 guys love those cutring gaskets as they seal the chamber very well, there is an m20 version looks like thats the pic made by JE (sold by them under license from athena it seems) its 2mm thickness and not big enough for 86mm i was told 85.5 but not sure if that is the bore of the rings or size of cylinder bore you can use (they werent 100% sure) i contacted CES. you would think they could simply supply bigger rings though, probably from some other engine already in existance to do the job and accommodate 86mm.....i never contacted the manufacturer directly
not exactly cheap either.

[Schlander]

Everyone i've spoked to mention that the stock kan be used, and that MM does it with their 86mm engines.

I've written to MM 3 times, three different places, no answer.. So know I have ordered a set of JE pistons instead from Qualitec here in Denmark instead.

He mentioned that he could provide a MLS 86mm gasket or a Athena like the one listed above with cutrings.

Thought that getting a gasket was the least of my problems, but now it seems that :rippedoff:

The setup is the following.

M20B25 block with 86mm bore
135mm S50B32 rods
JE pistons 86mm 12.5:1 compression
89,6mm M54B30 crank
885 head - maybe it's getting ported
272 schrick cam - not ordered yet
EMU ecu
Dreaming for a set RHD itb's

These pictures are from a friend of mine who just build one with 85mm bore.

[digger]

MM Pistons have a chamfer on the edge that allows use of oe head gasket and the piston probelm dont have the same protrusion from the block. You can't set up a proper set of 86mm Pistons with oe gasket because the piston comes out of the bore too far

[digger]

Everyone i've spoked to mention that the stock kan be used, and that MM does it with their 86mm engines.

I've written to MM 3 times, three different places, no answer.. So know I have ordered a set of JE pistons instead from Qualitec here in Denmark instead.

He mentioned that he could provide a MLS 86mm gasket or a Athena like the one listed above with cutrings.

Thought that getting a gasket was the least of my problems, but now it seems that :rippedoff:

The setup is the following.

M20B25 block with 86mm bore
135mm S50B32 rods
JE pistons 86mm 12.5:1 compression
89,6mm M54B30 crank
885 head - maybe it's getting ported
272 schrick cam - not ordered yet
EMU ecu
Dreaming for a set RHD itb's

These pictures are from a friend of mine who just build one with 85mm bore.

s50b32 rods are 139mm C to C and use a different big end size.

you need s50b30US or s52b32 rods (sourced from USA) or one from m52, m50nv, m54b30

[Schlander]

Damn, then I need to find some new rods.. I was certain that they were 135mm.

[digger]

Damn, then I need to find some new rods.. I was certain that they were 135mm.

yeah lots of info about s50 on web pertains to the US spec versions....

here is a list of different aftermarket rods for BMW's you can see which engines have different sized rods and which are common to the m20

http://pauter.com/parts/rods/bmw/