Compression Ratio, Too High...Too Low ??? |
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Compression Ratio, Too High...Too Low ??? |
2-OH! |
Sep 6 2007, 05:44 PM
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#1
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Senior Member Group: Members Posts: 552 Joined: 17-October 03 From: Santa Clarita, Kalifornication Member No.: 1,253 |
Ok folks,
We just finished rebuilding the motor...94mm pistons and cylinders to match...71mm stroke...but old 1.7 case...CC'd the heads and come up with 44 cc's per cylinder... Do the calculations and we come out with 1971 cc's...Great !!! But, The problem is the compression ratio is now 10.64 to 1... The question of the day: Should I take the cylinders and heads back off and shim them to get a little relief...Probably not going to get much...Might knock it down to 10 or 9.75 (if I'm lucky)... DO NOT want this thing to clatter and diesel on me when I get it back together... OK, let me have it...What are your thoughts ??? 2-OH! |
mike373 |
Sep 6 2007, 05:58 PM
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#2
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Member Group: Members Posts: 198 Joined: 3-August 05 From: san diego, ca Member No.: 4,536 |
Only if you plan on running jet fuel.... But seriously.... 10.64 is on the high side... and the cam that you are using will either benefit from higher or lower compression. I just built my 2056 with a Raby cam... and set the compression to 9.3 to 1. And some people I talked with said THAT was high.
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orange914 |
Oct 17 2007, 09:05 PM
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#3
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http://5starmediaworks.com/index.html Group: Members Posts: 3,371 Joined: 26-March 05 From: Ceres, California Member No.: 3,818 Region Association: Northern California |
Only if you plan on running jet fuel.... But seriously.... 10.64 is on the high side... and the cam that you are using will either benefit from higher or lower compression. I just built my 2056 with a Raby cam... and set the compression to 9.3 to 1. And some people I talked with said THAT was high. mike been watching your build as you have been a few steps ahead of mine. i'm assuming your running carbs with that c.r.? my 9550 and d-jet is recomended no more than 8.5... mike |
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