Carl Fausett

When I began developing the supercharger kit for the 968, I had several responses that the 968 suffered from weak head gaskets.

I have been supercharging the 928 for 10 years now, and the 968/944 head gaskets were designed using the same materials and basic design from the 928, so I had a headstart on the problem.

About a year ago we developed a line of modern head gaskets for the 928 and they have proven themselves very well. These use more modern materials (graphite-composite steel) and methods than the old paper-laminate OEM head gaskets.

I have just completed the design of the matching 968 head gaskets in GCS (graphite-composite steel) and I have a few of them in stock now, more on the way.

They will fit all 968 and 944S2's with 104mm bore.

In testing, we have run these gaskets up to 14 psi of boost on a 928 without a failure.

They also have a silicone outer sealant sprayed on them that really helps seal heads or decks that have a little corrosion on them. And a stronger fire ring than stock to handle boost pressures.

More pictures and information are available here:
http://www.928motorsports.com/parts/gcs_head_gasket.php

I dont want to start people worrying that they have to replace their headgaskets to install our supercharger kit - you dont. But, for those with trouble sealing their heads or taking our supercharger kit racing.... its nice to know there is an upgrade now available.

Damian in NJ

Beautiful, Carl.

Lemming

Any plans to make a thicker one for those of us with shaved heads?

Carl Fausett

According to our measurements, the firering on the stock headgasket is 0.060". Our gasket is 0.065", so this is slightly thicker than stock.

No plans to make any other at this time, until I see how these sell. The tooling for this part was expensive.

333pg333

Actually you'd probably sell a lot more if you made one for the modded 2.5 turbo crowd. There are lots of these guys running more than 20psi and the h/g is a weak link. Obviously there are alternatives to the stock h/g available.
Without bashing another brand, how do you see these as different from the other aftermarket products?

Rogue_Ant

+1

Tom M'Guinn

I'd try the 104 version on my turbo but would need widefire and ability to run with o-ringed block.

Thom

This HG would be a straight fit on my turbo... but you haven't tested it over 14psi?

Carl Fausett

From our webpage: http://www.928motorsports.com/parts/gcs_head_gasket.php

Carl Fausett

I presume your are talking about a multi-layer-steel head gasket like the Cometic brand. I am a Cometic dealer, so I can speak about that accurately.
I have sold, installed and used MLS head gaskets.

They are good, and they work, but they require extra care. Because they have very little yield, the head and the deck have to be very near perfect. Milling the head is common, but decking the block may also be necessary or they willnot seal.

Secondly, they require a re-torque of the head after 3 heat cycles. This is no fun on OHV engines should the camshaft or cam cradle shroud the head bolts. On a 928, its a real PITA. However, without retorquing, the probablility of a coolant leak is very high.

These GCS are different from MLS in these ways: the head and deck need only be reasonably good, as if you were installing an OEM gasket. In fact, the GCS gasket will even seal small corrosion pockmarks in the aluminum on both sides.

And there is no need to retorque these headgaskets after installation. Which makes for an easier installation.

Neither the MLS nor the GCS head gasket is compatible with stainless steel o-rings.

Carl Fausett

We did not design this for use on the 951 and I have not advertised it as such. It is a brand new product, so no, nobody yet has taken it above 14 psi. Im sure that will happen, but it hasnt happened yet.

For the intended application (968 and 944S2 with our supercharger kits) and 968 and 944S2 NA with head gaskets sealing problems, 14 psi is a great plenty.

Thom

Should there be any physical difference to a HG between a SC and turbo application? Both involve sending pressurised air into the cylinders?

Carl Fausett

Measured in cylinder pressure, no. Turbo or SC would be the same at this level on this part.

Not being a 951 expert - what boost levels do a stock 951 produce? And a modded 951?

Thom

A stock 951 (2.5L -> 100mm bore) runs 10-11psi.

FWIW I run a stock 104mm bore headgasket on my 3.0 turbo at 15psi, it hasn't blown up (yet) and doesn't seem it will blow up if I keep the boost that low. I suppose I will go as far as 20psi when I switch to E85. Several people who use the stock 100mm turbo HG seem to be running 20psi on pump gas without issues.

Carl Fausett

Ok, then it would appear that this gasket would satisfy the stock 951 if all the other coolant and oiling passages are the same.

What worries me is the Porsche PET part numbers for the 951 and 944 NA head gaskets are more than just a revision different... the entire sub-series is different between the two, suggesting more than a minor difference. I do not have a 951 block/head here to mount them up to.

Do 944 owners use 968 head gaskets commonly?