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?

[Superhawk996]

No discernible crank end play is a no-go.

Redo until it is correct. Likely shims weren’t correctly measured / calculated. There is no harm in doing this several times to be sure it’s correct. When doing the mockup / measurement of shims the flywheel must be fully installed and torqued so that the flywheel s firmly seated to the crank. Personally I set and measure end play before installing the RMS since you need to remove / install flywheel several times to get the right shim selected and measured.

Disregard spinning the crank measurement that has no relevance to crank end play.

Hint #1: when you make this measurement the dial indicator must be perpendicular to the the flywheel. May just the the angle of the photo but to me it looks like it is at an angle.

Hint #2: mount your dial indicator to the engine. You want the relative measurement between the case and the flywheel only. Mounting the indicator to the engine stand adds error and uncertainty to what you are trying to measure . Alternatively you could have the magnetic base on the flywheel and the dial indicator touching off the case.

[sdoolin]

No discernible crank end play is a no-go.

Redo until it is correct. Likely shims weren’t correctly measured / calculated. There is no harm in doing this several times to be sure it’s correct. When doing the mockup / measurement of shims the flywheel must be fully installed and torqued so that the flywheel s firmly seated to the crank. Personally I set and measure end play before installing the RMS since you need to remove / install flywheel several times to get the right shim selected and measured.

Disregard spinning the crank measurement that has no relevance to crank end play.

Hint #1: when you make this measurement the dial indicator must be perpendicular to the the flywheel. May just the the angle of the photo but to me it looks like it is at an angle.

Hint #2: mount your dial indicator to the engine. You want the relative measurement between the case and the flywheel only. Mounting the indicator to the engine stand adds error and uncertainty to what you are trying to measure . Alternatively you could have the magnetic base on the flywheel and the dial indicator touching off the case.

Thank you Superhawk. I only installed the RMS as I had measured for the third shim and figured (wrongly) that I'd be good to go. I will re-measure all of this, and will attach the dial indicator to the flywheel as you suggest. I had not thought of that. I have a total of 6 shims, so hopefully some combination of them will work.