Rebuild MHG Opinion

[MKIIITrbo89]

My engine is currently being rebuilt. The block and head were both machined extremely smooth. The MHG I am using is a 2mm HKS Stopper. From reading the posts I have always read people using either the silver spray or Permatex brake quite to seal the gasket. However my mechanic said a sealent should not be used with the HKS MHG. He told me HKS specifically says not to use any sealant. Apparently the MHG has a thin rubber coating on it which makes the seal when you torque it down. Is this true. What are peoples thoughts.

 

[Wreckless]

I've done 2 or 3 rebuilds at this point with MHG's, My first was a copper spray coated Greddy 1.5mm but it failed in part because of the coating and in part because of crappy prep work.
my past two motors I've done have been with HKS 1.2mm bead MHGs and I've not coated them, and I've had no issues other than needing to retorque the ARP headstuds after a few heat cycles.

If you've done the proper prep, leave it bare and just torque to the ARP specs. If you've got shoddy prep work the Permatex brake quiet or copper coating can help make an MHG seal but its not ideal at all.

HKS and Greddy both strongly recommend not using any kind of coating.

 

[MKIIITrbo89]

Wreckless, thanks. Everything should be good then (fingers crossed), the machine work is excellent and I have ARP studs. ARP recommended to torque it down to 80lbs. So that's what I'll do. I know there are some people that go higher than than but I think should be good. should I worry about retorquing the studs after a few heat cycles?