Deck Height Question Options

[clarkcou]

Building a 1.7, 90 mm piston/cylinder. With no base gasket, deck height is .013in. Shouldn’t the head gasket/ shim be included in the deck height.

Barrel shim, not yet installed, is .21mm. Head gasket is .068.

Seems to me that deck height would be.082 without barrel shim. I.e. .013 plus .068.

Thoughts on this please?

Randy

[Montreal914]

I am sure others will chime in but per Porsche bulletin many years ago, head gasket are not recommended. 0.040" is the "standard" deck height you are looking for. Shims should go under the barrels. I had a custom thickness one machined for me on my rebuild. Not sure multiple stacked ones are recommended, I doubt it.

That being said, head chamber volume, and deck height should all be considered to calculate your compression ratio, assuming you have flat pistons.

Good luck with the rebuild.

Edit: Sorry, to answer your question, yes under barrel shims should be considered in the deck height measurement and cylinders should be held down on the block with head torque value simulating assembly.