2G What head gasket

[gst-turbo]

Recently got my motor back from the machine shop and can’t figure out what head gasket to run. Machine shop recommended 0.35 to 0.40 thickness and 85.50 bore and can’t seem to find one in mls. Motor is a 2g with Wiseco 10.1 compressor with Manley rods on stock crank. The motor is bore over 0.20 and head has ferrea valve and both have been resurfaced. I have L19 head studs looking to run under 33 psi on fp black, how can I confirm what head gasket I need? And what brand of head gasket would you guys recommend? From reading on here looks like the fel pro mls

 

[DSMPT]

Recently got my motor back from the machine shop and can’t figure out what head gasket to run. Machine shop recommended 0.35 to 0.40 thickness and 85.50 bore and can’t seem to find one in mls. Motor is a 2g with Wiseco 10.1 compressor with Manley rods on stock crank. The motor is bore over 0.20 and head has ferrea valve and both have been resurfaced. I have L19 head studs looking to run under 33 psi on fp black, how can I confirm what head gasket I need? And what brand of head gasket would you guys recommend? From reading on here looks like the fel pro mls

The Fel-Pro MLS is .055" and the standard Cometic is .051". If you are specifically looking for a metal gasket with 0.35" ~ 0.40" thickness, would be Cometic by choosing thickness (Please refer the link below). And HKS has 1.2mm gasket, too. which is approxi .047".

https://www.dsmtuners.com/threads/a...d-studs-part-numbers-catalogs-for-dsm.533201/

I would say all would work well if you install properly. IMO, the preparation and installation would be more critical than brand name. I have used all brands and actually all worked great. But if I have to choose one brand, HKS gasket has the best quality, but it would cost twice more than Cometic.

 

[TheFlashDSM]

Recently got my motor back from the machine shop and can’t figure out what head gasket to run. Machine shop recommended 0.35 to 0.40 thickness and 85.50 bore and can’t seem to find one in mls. Motor is a 2g with Wiseco 10.1 compressor with Manley rods on stock crank. The motor is bore over 0.20 and head has ferrea valve and both have been resurfaced. I have L19 head studs looking to run under 33 psi on fp black, how can I confirm what head gasket I need? And what brand of head gasket would you guys recommend? From reading on here looks like the fel pro mls

okay this is the brand i used for my build! copper gasket with a built in SS ring, they offer different sizes
the link is all 6/7 bolt gaskets, in different bores and thicknesses

https://www.scegaskets.com/product-category/mitsubishi/4g63-2-0l/4g63-head-gaskets/

 

[motomattx]

Stock Mitsu, I wouldn't recommend mls gaskets, many records have been set over and over again on a composite gasket.

 

[gst-turbo]

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Wouldn't I need a thicker gasket if my head was resurfaced and block deck. The machine shop recommended thinner than stock? I got my head back from the machine shop and looks like my head has tiny holes on the head. This shop is well known on doing 4g63 engines and 2jz. Should I be worried about dealing with the small holes

 

[DSMPT]

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Wouldn't I need a thicker gasket if my head was resurfaced and block deck.

It depends on some factors, like how much you shaved off the material, what compression/piston to valve clearance/squish clearance you want, etc. If you are worried, should ask the shop for more details.

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The machine shop recommended thinner than stock?

As you stated that the shop recommended 0.35 to 0.40, it's about the same as the compressed thickness of stock composite gasket.

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I got my head back from the machine shop and looks like my head has tiny holes on the head. This shop is well known on doing 4g63 engines and 2jz. Should I be worried about dealing with the small holes

If I were you, I wouldn't be worried too much, especially if with a composite gasket. If with a MLS gasket, I always use copper spray when the head has some pits on surface or the surface finish is not good enough for a MLS. This is maybe just me, my way. So you should also ask your engine builder, he would know the best about your engine.

 

[dustyboner]

how much did they remove from the deck and head? the limit for the head and block combined is .008"

they may have tried to keep it in spec which would explain why you still have the pitting showing on the head.

I may be wrong but i would think that they would have removed more material on the head to remove the pitting, and recommended a thicker head gasket to make up for anything over .008 that was removed.

like DSMPT already said, you should be fine with a composite head gasket
==================================
here is a little bit of good info on surface finish from enginebuildermag.com

If you are building a street performance engine that has a cast iron block and aluminum heads, and are using conventional steel/fiber composite head gaskets or expanded graphite head gaskets, the surface finish should ideally be 60 to 80 Ra (360 to 480 Rz).

Don’t go smoother than 40 Ra (240 Rz) or rougher than 100 Ra (600 Rz) with a composition gasket. Rougher surfaces limit gasket conformance, while smoother surfaces increase the tendency for gaskets to flow, reducing the gaskets blow out resistance.

If you are using a stock MLS head gasket, the surface finish should be 30 Ra (180 Rz) or less unless the MLS gasket has a thicker coating that can seal a rougher surface. Note: Never apply any kind of sealer to a MLS gasket! It may react with the coating and cause a problem.

Though Ra (Roughness Average) has traditionally been used to describe surface finish, most gasket engineers today say a more accurate perimeter is Rz, which is the average difference between the peak height and valley depth. Ra can have a wide variance across a given surface profile, so Rz gives a better indication of the actual texture across the surface.

To measure Ra or Rz, you need a profilometer. If you don’t have one, you are shooting in the dark and assuming the surface finish you’re getting is in the ball park. Maybe it is and maybe it isn’t. The only way to know for sure is to actually measure it. Most dry milling machines with the proper CBN or PCD cutting bits can achieve an extremely smooth surface finish.

 

[DSMPT]

Note: Never apply any kind of sealer to a MLS gasket! It may react with the coating and cause a problem.

Just a little tip.
As everyone knows the best/right way is of course to get the proper surface finish for MLS and the coating on MLS would work good and would seal the best. But in case if you can not get the proper surface finish, the copper spray would actually work well. This is confirmed by many, including myself, especially good for someone who wants to use a MLS but lives somewhere hard to find a machine shop that can do the proper surface finish for MLS.
But this doesn't mean you don't need to resurface, resurface the both side is a must for using a MLS.

 

[jed344]

The thickness they recommended i would guess is to try to get quench area to ideal spot. That thickness is right inline with a composite when compressed. A composite will hold your goals, otherwise if they finished the surfaces to correct RA for a metal layer take your pick. Cometic makes one in that thickness. I myself went from a metal layer back to a composite with O rings. This was after a cometic pushed coolant that was copper sprayed. The head had SS O rings at .005 protrusion, L19 studs. Was at high 40's for boost on a 67mm hx40 so may have been creeping into area where it would have pushed without spray or O rings, who knows. Went down to a 6264 holset now and limited boost to around 40psi.