I can't decide which head gasket to buy for my turbo build

[Yuri]

I can't decide which head gasket to buy for my turbo build


I was ordering an MLS head gasket today and they only had 85mm bore size. If I remember correctly the stock bore is 84mm. Is that an issue?

That being said, VAC only stocks the MLS 85mm x 0.120. My head has been machined so I wanted a taller HG while also lowering compression for the turbo. But from what i hear thick head gaskets can create new issues.

That's when the sales guy told me about the Cooper Ring - Cutting Ring Head Gasket -

https://store.vacmotorsports.com/cooper-ring---cutting-ring-head-gasket---bmw-m20-p3632.aspx

These are only available in 85.5mm bore and 0.080" thickness. So this would bring me back to stock compression and be able to hold higher boost; however, the bore size is too big and I don't get the compression benefits.

What do you guys think about the gasket bore size difference and which, if either should I purchase?

I wana run crazy boost like 15 daily with the option of 20 down the road.


What do you guys think?

[Yuri]

Here are some picture of the project so far.

[CrazyPrime]

I have used 2 MLS head gaskets on my turbo m20 and they have both leaked oil and also leaked pressure. I don't have any experience with the cut-ring gaskets. I think O-ringing would be preferred since you wouldn't have to resurface the head like the cut-ring gasket. and you would just use a stock gasket.

[Yuri]

i bought the motor im building now from a guy who used a mls and had the same problem as described..

[ForcedFirebird]

I have been using MLS gaskets for about 15 years. If your block and/or head don't have a proper finish on them, the gaskets leak. Easy remedy is to drill out the rivets and spray both sides of each layer with copper spray.

Lately I have been using OEM head gaskets and o-rings more often since I purchased the Isky tooling. (whatever you do, stay away from Elring or VR for the m20)

Why do you need to lower compression? That is such a myth for older engines as they only have 8.8:1 anyways (which is prefect for boost). I have had great success going as high as 10:1. Local here has an e39 m5 with 11.5:1 and runs it at 1bar through a supercharger. I have put countless turbos on m20's t my shop over the years - many of them were completely STOCK motors. Once you start getting over about 13psi on a 60-ish mm turbo (~250-300whp), the gasket will want to push. With studs and stock gasket, I have a daily driven e30 that has been on the road for years at 13psi on a 54mm turbo. MLS, I have pushed the m20 over 500whp with no issues (and it didn't leak ;)). I haven't tested the limits of the o-ring yet, but so far I would say they are taking the same abuse the MLS did.

EDIT: Also, it's standard procedure to have the head gasket bore larger than the cylinder. It leaves room for over sized pistons.

[Paul-Z]

Don’t remember the bore size but I’m running a .120 MLS with no issues. Like the previous posted stated, if it’s installed correctly you should have no issues.

[E30-Ellerman]

I have an Elring with APR studs at 11psi no issues. Good buddy has an Elring with APR studs on his 17 psi boosted M20 (with meth) at 350-400 whp and hasn't had any issues.

[ForcedFirebird]

I have an Elring with APR studs at 11psi no issues. Good buddy has an Elring with APR studs on his 17 psi boosted M20 (with meth) at 350-400 whp and hasn't had any issues.

They hold the same as OEM or Goetze, but Elring and VR both leak oil at the front passenger side of the head. There's about half of the silicone embedded in the VR/Elring vs OEM or Goetze. If you held both in yoir hand at the same time, you would have no doubt which to use.