Adamant1971

So the 89 block is coming together well. My machine shop took 3 tho off the heads and the block deck. so 0.0762mm off of each. Just a light skim.

Total material removed is 0.14mm and being that the thicker head gasket is 0.30mm thinker I will be increasing the distance between the head and the block by 0.16mm if I use the 1.4 mm head gasket.

At this point I'm leaning toward going with a 1.1 mm gasket. But I still need to drop a couple pistons in so I can double check the measurements on the block.

My head measurements are 146.89 mm & 146.79 (variance likely due to my digital caliper).

Would you go 1.1 or 1.4 for the gasket?

Imo000

As a precaution I would go with the thicker gasket. This way future carbon build up will less likely cause detonation and I don't think the compression ratio difference will be noticeable when driving.

SwayBar

I would definitely go 1.1 because of the better squish.

V2Rocket

1.4...
squish isn't so important on a pent-roof DOHC chamber like his S4 has.
assuming 0-deck...
the piston-to-head distance on a stock engine with stock 1.1mm gasket would be 1.1mm.

with his engine, with the 0.16mm total cut, but with a 1.4mm gasket, the piston-to-head distance would only be increased 0.005" vs fully stock.

Adamant1971

Ok we are going to go with the 1.4mm gasket.

Thanks for the advise everyone.

ziim

Greetings.

I`m currently rebuilding a M28/09 with M28/11 heads.
Heads are rebuilt and the height of those edges are ~23,6mm which requires thicker head gaskets. Now to the problem - I haven`t able to find 1,4mm gaskets for 4.5 engine. Did Porsche ever made them or are those only for 4.7 and up?