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! |
Heeltoe914 |
Sep 10 2007, 12:07 PM
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#2
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Senior Member Group: Members Posts: 1,135 Joined: 31-January 06 From: Tujunga Calif, Member No.: 5,506 |
Clayton:
I would say from seeing this motor and the heads that the Heads are decked way to much for any stock configuration. Many assumption where made to the quality of the first Eng build and we are not even sure if the barrels have been cut in anyway????. If the shims are simply placed under the barrels and the cam requires a certain CR Rick will have other problem. I watched the injection of oil for the CC test that was preformed and would say the reading of 44cc is correct for what that head was cut to. I should also mention that the crank had some Major work done on it from what you will see in the pic. So we have a ? crank, cam 73 grind what CR. piston no real notch for valves, barrels maybe cut, heads cut to much, To many ????. My feeling is all parts should be spec’d and calculated by a competent machine shop, JMHO. Great info and feedback to this problem This is the root of the 914world, Attached image(s) |
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