Who has the secret decoder ring for machinist to increase CR? |
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Who has the secret decoder ring for machinist to increase CR? |
stugray |
Jan 13 2012, 05:52 PM
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#1
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Advanced Member Group: Members Posts: 3,825 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None |
So I converted my car to carbs for vintage racing and have the Raby race cam.
I know I need to increase my compression ratio to make this work out. Who has the numbers for "Cut 'X' from the combustion chamber to get 'Y' compression ratio? I have measured my deck height and CCd my heads and everything I have now appears to be exactly stock. Someone has done this before. I have a machinist that can flycut the heads (they are in great shape), but he wants me to tell him exactly how much to take them down. I am targeting a 9.5:1 for now with the stock "slightly dished" 94mm pistons. I can get a little more increase by switching to flat tops if I want. Stu |
Mark Henry |
Jan 14 2012, 09:59 AM
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#2
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
Try to change the CR with shims first. I would set the deck height at .060" and figure out the CR before I cut anything.
You can only cut so far before you run into clearance issues with the top fin on the cylinder. |
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