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JohnJL JohnJL is offline
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Join Date: Jan 2005
Location: Toronto, Ontario
Posts: 4,726
Hi Tom, thanks for the reply.

I am using Jim William's method, here:

http://members.rennlist.com/jimwms/Tech/comp_ratio.html

WRT your comments:

1. Yes, worringly so. However I understand that twin-plugging also removes enough material in the head to add several ccs and so bring down the CR a bit.

2. I measured the heads 6 times, each giving the same results. That included flipping the glass plate over, removing and re-greasing the edge, etc. I am pretty sure those are accurate measures. I had a few thous removed from the head at the mating surface to deck everything perfectly flat. That might account for the trade off where my single-plug cc's the same as your twinplug heads.

3. I measured 1.55mm deck height with a single standard .25 copper gasket. That's much higher than I had hoped for, and is another reason why I think I may need to go twin plug. I am concerned about detonation originating at the edges.

4. I'll give the level-trick a shot when I get back tomorrow. Could you send the spreadsheet?

thanks
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Old 10-23-2005, 11:58 PM
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