DLS

thanks for all input
looks like itīs a good idea to o-ring the head anyway

toddk911

How far to you update/protect yourself with the headgasket, but allow a "safety blow" so the motor is self is not blown??? As many say it is better to blow a HG than the motor.

I, as some may know, just developed a leak at the #4 on my 2 year old WF gasket, decked head, non O ring and been running 18psi for 3+ years with a good/constant state of tune and boost.

Yet, I still now have a blown heasgasket..... ???????

I have heard conflicting stories on this issue since I have been on this board. Some say no way you should run over 15psi on stock hg and you need WFR. Others say the WFR is prone to cracks unlike the stock hg. Some say run copper but then the issue as stated above is a blown motor/fried piston over a hg repair.

What is the difference in the WFR vs. MLS???

clouddomino

The widefire gasket is a "paper" gasket, where as the MLS is as earlier stated by Porschefile "A multi-layer steel gasket". I myself am in the process of switching from WF gasket and copper o-rings to copper gasket and ss o-rings. Van has a great diagram of the set-up earlier in this thread.

clouddomino

Oh and as experience has proven in my cause 21+psi of boost seems to be the WF's weakness

TRP951

Special tool has been running a WF gasket on 30+psi of boost but then again he always says how **** he is with his perfect tune

95ONE

Which supports my point. (Along with the hundreds of other cars running stoopid boost with stock headgaskets.) A correct tune is directly involved here. No matter what your boost. It might be common in our cars, but the underlying "common" problem is most likely the old crumby chipsets, or none at all. (Could argue forever on this one, as had been done, but this has been my DIRECT experience for over 5 years.)

Porschefile

I think that should be considered the exception or not the norm. On plenty of other non-951 cars, people blow their oem paper type headgaskets long before that usually. It doesn't matter what kind of car you have, you are asking for trouble running an oem gasket with that much boost.

You never want to use the headgasket as a "fuse". That's not a good idea. Blowing the headgasket at all can cause serious damage to lots of different components as the motor will tend to overheat very quickly. You want to do everything possible to prevent the headgasket from blowing.

hosrom_951

As well as stock studs, re-used a couple of times (or more?)

toddk911

So, as in other threads it does seem that pressure does not blow HG, heat does. Heat in all of it's forms; by overheating, bad tune, etc.

But, if you o ring the head then you have to go with a full metal/custom HG right???

toddk911

Anyone running a MLS gasket and still blown it??? if so, at what boost???

Porschefile

Yeah but, increased cylinder pressure will require more clamping force to keep the head on the block. Fiber type gaskets don't work nearly as well as metal gaskets at maintaining clamping force. More hp and more boost is going to require more clamping force. ST may have gotten away with it for awhile (I'm still surprised) but, recently he's had trouble with head lifting so I wouldn't exactly take that example to mean you can run 30psi on stock studs and a stock/widefire HG with a good tune. Hell, in other car circles, most people don't tend to use fiber HG's over 300-350whp as it's just a waste of time when a metal headgasket will work better and be safer. In fact, this is the only group where I've ever even seen people talk about, think about, and even attempt to run fiber gaskets over 450whp. There's a reason a large amount of car manufacturers (including Porsche as previously mentioned) have moved to metal gaskets on stock production cars.

Todd, I believe there was someone here that posted about blowing an MLS gasket (could have been another forum though). It's definitely possible. Serious detonation can blow holes through pistons and it can certainly damage MLS gaskets. MLS gaskets are much more resistant to detonation and other factors though, so they are less likely to be damaged than a fiber/oem/widefire gasket will. The whole "fuse" method is kind of an urban myth or misconception. That's kind of like using a weak clutch so that you don't put down too much power and break the axles. It's just not the right way to go about it. If someone blows an MLS headgasket, I'd be willing to bet that it was a result of horrible detonation, in which case anything in and around the combustion chamber would be prone to destruction.

TRP951

I think chris white posted a picture of a blown headgasket on the #4 cylinder a while back

hosrom_951

Chris and tony g blew the MLS gasket

Bill

For the past year and a half, My boost has been set at 22 psi. I use a wide fire head gasket with O-rings in the head. The O-rings, a five angle valve job and some port work were done at Lindsey Racing.

mj951

DLS, thanks for starting such a great thread.
Rennlisters, thanks for all the valuable information, technical descriptions, pics and diagrams.