Deck Height and Valve Relief, What would you do? |
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Deck Height and Valve Relief, What would you do? |
BeatNavy |
Mar 4 2019, 06:44 PM
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#1
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region |
While I wait (seemingly forever) for back-ordered rocker shims to arrive from aircooled, I keep debating in my head which way to go on deck height on a 2056 rebuild I am doing:
CC volume is 59.8 (calculated by Len Hoffman) Raby 9950 (FI) cam JE Pistons with valve relief Deck height w/o any barrel shims is .032. That gives me a CR of 8.6, assuming the valve relief adds about 2 cc's to CC volume. Adding a .010 shim puts me just shy of 8.4 CR with a deck height of .042. .042 deck height is safer. Pretty sure I wouldn't go .032 deck height with flat tops, but does the valve relief give me enough "safety?" This is my first Type 4 rebuild, so maybe I should go conservative? Am I crazy considering going less than .035? I've done the "clay test" with deck height at .042, and there's no issue there. What would you do? |
BeatNavy |
Mar 4 2019, 07:03 PM
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#2
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region |
So I should probably add: I did go to my "local" machinist (about an hour a way) and had him cut .035 off the jugs a few weeks back. I should have had him take a bit more, but I didn't think it all the way through -- that's my fault. Having him do additional work is a couple of 2 hour trips, $100 in services, and, likely, 2 to 3 weeks waiting. None of that is a deal breaker, but just trying to determine my options.
So I guess the straightforward question is: what is safe/acceptable deck height with valve relief? Still .040? .035? Thanks for the input, fellas. |
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