Compression Ratio, Will I be able to tell the difference? Options

[sdoolin]

Rebuilding(ish) my 2056. On my first build I was able to achieve a compression ratio of very nearly 9.0:1. With this build, I am having to add .020 spacers below the jugs to get any measurable deck height in the jugs. I am calculating a compression ratio of 8.6:1.

Will I notice the loss in compression ratio?

[sdoolin]

Superhawk thank you for your reasonable response. I add the 1mm to overall deck height at the instruction of Len Hoffman at HAMM. I trust him. I really do.

[Superhawk996]

Superhawk thank you for your reasonable response. I add the 1mm to overall deck height at the instruction of Len Hoffman at HAMM. I trust him. I really do.

Len is an expert no doubt.

But, is it possible you misunderstood? What was his recommendation for deck height not including his head?

Unless you can guarantee the heads have been machined to have a slightly larger OD of the sealing surface than the OD of your cylinders you have a potential for contact between the piston and the head.

I don’t see how you can be running .6mm deck clearance and still only netting a 8.6:1 CR.

Proceed at your own risk. At a bare minimum I’d be triple checking the fit with Prussian Blue and then double checking the piston top with clay.

Tread carefully.