This may be common, but it's not normal, and it's not necessary. Don't believe for a minute that everyone with a high HP motor is experiencing these issues.

 

I don't have much experience, but from a layman's perspective, why is it that AMS head studs exist? ARP is obviously good hardware, but AMS felt there was a need for something better. What problem did they hope to rectify with this new hardware?

And to some extent I think it depends on the fuel used and the torque being created. With a fuel like VP Import, it will almost never det, so your left with exactly what physical restriction when tuning?

CO_VR4... do you personally know of a 600+ ft/lb Evo that does not push coolant? If so who and what type of gasket, hardware, torqueing procedure did they use?

 

The AMS and Cosworth head studs have a higher yield strength than standard ARP's. This issue is why they are around. Drilling for a 12mm stud won't get you far. Ask any DSM guy with a 6 bolt motor that lifted the head off with 12mm ARP's. Those guys drilled for 1/2in ARP's back in the day. (Because the L19 stud wasn't available in a 12mm then) So they moved to a larger, and stronger stud.) But this is not 8 years ago. Stronger drop in studs exist now. Use them.

I hate it when people blame the tune entirely for pushing the head off. This is not always the case, there are ways to spike cylinder pressure (intentionally) without it being knock. Especially on race fuel. On top of that, I have seen people push them off without doing so, just with boost. Especially on standard ARP's.

Many will nitpick and argue, but I've seen clean logs and lifted heads.

The solutions to this are in this thread already. Heavy stud, stock head gasket, and o-ring if that doesn't work.

Buy better studs. The difference in price is less than one head gasket job.
The extra margin of insurance is a common sense issue, regardless of your opinion about the "why's". Even the perfect tune isn't perfect 365 days a year. So cover your ***.

 

Very true!

However we have our 2G DSM that just put down 606HP on our Mustang Dyno but unfortunately it pushed coolant AGAIN after installing a head that was O-ringed by a reputable vendor here as well as runnning the Magnus studs and oem hg.

We obviously need to look into what may be causing the issue.

The head was machined i believe when they did the o-ring work but maybe the block is not 100% flat

This was the 3rd hg in about a month......needless to say we are frustrated and boggled by the results as we tend to tune cars very conservatively

 

Thanks for the input guys, this is the 2nd time someone has highly recommend the FELPRO gasket which I intend to use.

I really don't intend to O ring thus I will try with the new gasket and whats the torque figures to torque the head to on the AMS studs?
90? 100? Am on 70 now.

 

I though seeing a reservoir fill up a couple inches was normal

 

Without actually inspecting your surfaces, but from what you are posting its sounds like your O-ring is your problem. If there is anyone that has done the most research in sealing 4G63's it is us. I can tell you what it takes to seal your motor, at any boost level, and at any power level that you are looking for. Because we have done it successfully many times before.

 

^^^ What He Said ^^^

 

Exactly why I ordered the FELPRO's from you recently...

 

I believe the instructions for the AMS studs are 90ft/lbs.

So Magnus rec using Felpro HG's instead of oem

 

Felpros have a better sealing capability because of the type of construction of the center layer, among other things.