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Posted by: KevinP Feb 13 2009, 04:58 PM

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

Posted by: Dr Evil Feb 13 2009, 05:33 PM

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.

Posted by: Joe Ricard Feb 13 2009, 07:42 PM

What makes you think your cylinder heads were exactly the same before.

Sometimes they pair can be significantly different.

Posted by: Dave_Darling Feb 13 2009, 11:58 PM

Do it again. A cc or two is enough to make a difference... Make sure they're still the same volume.

--DD

Posted by: Jake Raby Feb 14 2009, 11:37 AM

What if the heads had a volume differential before??
Never assume anything. Check everything, every time.

Posted by: KevinP Feb 14 2009, 03:51 PM

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

Posted by: Jake Raby Feb 14 2009, 05:38 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.

Posted by: r_towle Feb 14 2009, 05:45 PM

QUOTE(Jake Raby @ Feb 14 2009, 06:38 PM)