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Cylinder deck height

I am in the process of rebuilding my 1.7 with 96 mms big bore kit and 1.8 heads everything else stock I was told to set deck height to .40thousand but my deck height with no shims is .63 thousands case is already put back together mill cylinders ?
Old 06-18-2017, 02:06 PM
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IIRC, it needs to be at least .040" for valve clearance. If it's more it's not the end of the world just factor in those numbers when you calculate for compression.

My deck height was .055" I measured 16 times in 8 different places and averaged all the numbers together. All of the measurements were very close.

With this deck height I did not use any spacers, only a thin layer of sealant.
Old 06-19-2017, 05:45 AM
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Deck height is a fairly important quantity in setting compression ratio. If you haven't yet CC'd your heads, that would be a very good thing to do. Relatively small differences in head volumes or deck heights can make surprisingly large changes in compression ratio.

Don't let the deck height get below about 0.040", or you start risking your valves contacting your pistons. There are people who set it closer, but they do a lot more work to figure out what they can get away with.

You can cut the heads or shave the cylinders if you need to reduce deck height.

--DD
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Old 06-19-2017, 08:39 AM
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Cylinder deck height

Checked all cylinders today vary from .052to 0.63 cc heads today 61.5 ,96 mms cylinders if I cut cylinders down to .040 compression will be 8to 1
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Try to get things as even as possible.

8:1 compression is fine. (If you're putting in a super aggressive carb-oriented cam with a lot of overlap you'll probably want higher.) You should even be able to run mid-grade fuel with that.

--DD
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