948 head gasket

[RustyRick]

I’ve got a problem with a 948 Herald. Engine No KA5172 - the mysterious Australian 948... 

It’s blowing head gaskets between 3 and 4. The heads been planed, and the block is flat. We’ve been using the high compression shim gaskets coated with a thin gasket paste, torqued down to 46 lbs. The standard copper gaskets are getting hard to find. 

My question... What should the torque be? And has anyone else had this problem? 

Lastly, I assume that a 1200 head gasket won’t fit.

 

Rick

[Pete Lewis]

948 is 63mm bore   1147 is 69.3mm   so not really a fit it would give a 3.1mm recess around the fire ring zone .

looking at the poor pics on line theres some changes arounds the pushrod gallery

GEG344 seems pretty unavailable around most usual suppliers  

I wonder what other 948'ers do ?

Pete

[RustyRick]

Yep, what do others do? What makes it worse is our Customs agency have cracked down on importing cars and parts that may contain asbestos, so buying NOS gasket sets is a problem.

[RustyRick]

Ok, just for the record. A successful race engine builder near me said the shim (thin steel) gaskets need to be treated with care. The block and the head have to be dead flat. Even a .002” dip between cylinders can cause a failure. The gasket has to be coated with a copper gasket spray and left to dry. Assemble and torque the head up in 3 stages. Leave overnight and redo. Run the engine until warm, leave till cool and retorque to the recommended level.