 Compression Ratio, Re-"ccing" head |
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| KevinP |
 Feb 13 2009, 04:58 PM
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#1
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Member  Group: Members Posts: 205 Joined: 16-November 04 From: Orlando,FL Member No.: 3,127  |
I had my plug holes relocated and went to the smaller plugs.
Question is- do I really need to re-cc the head? I wouldn't think that the volume would not change any more than a half "cc" at the most. I guess that small amount could make a sizeable difference in the CR calulations. Probley only take me about 15 minutes to set up and do the measuring again. Thoughts anyone.... TIA KP |
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| Dr Evil |
Feb 13 2009, 05:33 PM
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#2
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Send me your transmission! Group: Members Posts: 22,995 Joined: 21-November 03 From: Loveland, OH 45140 Member No.: 1,372 Region Association: MidAtlantic Region 
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How close are your CR tolerances? If a slight increase of decrease wont mess up your power or ability to use the fuel you wish then I wouldnt bother.
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| Joe Ricard |
Feb 13 2009, 07:42 PM
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#3
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CUMONIWANNARACEU Group: Members Posts: 6,811 Joined: 5-January 03 From: Gautier, MS Member No.: 92 |
What makes you think your cylinder heads were exactly the same before.
Sometimes they pair can be significantly different. |
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| Dave_Darling |
Feb 13 2009, 11:58 PM
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#4
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914 Idiot Group: Members Posts: 14,986 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California
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Do it again. A cc or two is enough to make a difference... Make sure they're still the same volume.
--DD |
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| Jake Raby |
Feb 14 2009, 11:37 AM
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#5
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
What if the heads had a volume differential before??
Never assume anything. Check everything, every time. |
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| KevinP |
Feb 14 2009, 03:51 PM
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#6
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Member Group: Members Posts: 205 Joined: 16-November 04 From: Orlando,FL Member No.: 3,127 |
The heads were the same before I had the the plug holes relocated. ( Len Hoffman did the work for me). I had cc'd them before the work. Now that I have gone to the smaller plugs of course the over all volume is going to change some. I am going to remeasure again but I was wondering how much of a real difference I should expect to be seeing in The CR ratio due to this small change in volume.
Thanks for everyones thoughts on this matter. I didn't know what to expect to see when I remeasure. KP |
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| Jake Raby |
Feb 14 2009, 05:38 PM
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#7
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
If Len did the work I am sure he measured chamber volumes after the work was done and balanced them if need be. Len covers all the bases.
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| r_towle |
Feb 14 2009, 05:45 PM
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#8
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Custom Member Group: Members Posts: 24,574 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
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QUOTE(Jake Raby @ Feb 14 2009, 06:38 PM)  If Len did the work I am sure he measured chamber volumes after the work was done and balanced them if need be. Len covers all the bases. Yup, from what I have seen he writes the CC volume right in the chamber. Rich |
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