[Supras] headgasket project

[Khalid Almufti]

I have to agree with Jeff. To begin with, doing a "proper" surface prep is not possible by most machine shops (can't do wet grinding nor lapping) to achieve the mirror polish required for MHG.  Secondly, from my experience, after I initially installed my MHG (after surface prep), which is a Greddy 2MM, and torqued to 85 ft-lb, still it didn't seal until I went through a complete heat cycle, i.e. let the engine get to normal operating temperatures and THEN retorque the bolts (ARP in may case) to 85 ft-lbs.  I had zero leakage in the HG since then.  That was 10 years and 80K miles ago with over stock boost.  

So, as Jeff mentioned, I would not try to go to the MHG route unless your going to have the block decked, head resurfaced, both block and head surfaces perfectly square, and finally expect to have to retorque after full heat cycle.  As for my choice of MHG, I'd vote for the Greddy simply because of my trouble free experience for such a long time.  But I imagine other equivalent brands are just as good.

Regards,
/Khalid
90T


Date: Thu, 9 Apr 2009 19:01:34 -0700
From: Jeff Mohler <speedtoys.racing at gmail.com>
Subject: Re: [Supras] headgasket project
To: john p <longjohn_69_3 at hotmail.com>
Cc: supras at supras.com
Message-ID:
    <a969fbd10904091901x44fa1af3k992d73d17474c099 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

OEM is extremely reliable, with a good torque on the OEM bolts, with only
moderate preparation, and <350HP.

A MHG is extreme unreliable, unless EVERY step to prepare for it isnt tits
perfect, from cleanliness to machining to prep to bolt torquing.


When this list was really moving in the late 90s, early 2000s, the # of
people on multiple MHG installs from issues in cleanliness, prep,
install..etc..was really quite interesting.

Ive run 100+HP NOS shots on a MHG with the OEM bolts simply re-torqued to
75lbs with no other work, and been fine..would do it again.

Its not the HG, its the torque value of the bolts.


Some people have stopped a leaking HG, with a retorque as well.



On Thu, Apr 9, 2009 at 6:38 PM, john p <longjohn_69_3 at hotmail.com> wrote:

>
>
> hey jeff isnt there a big difference in reliabilty when it comes to the
> mhg...how much easier will it be by going with the oem gasket.....i wanna do
> this once and right so time i dont mind spending cause i have had her for 5
> years now soooooo.lol
>
> jeff where you from bud?
>
> be2nice thanks
>