Ron,
Excellent point. Hmmn, Stephan, did you shorten the stroke or modify the
chamber on the head? (And you guys are sure brave to play around with this
stuff!)
Fred
_________________________ Reply Separator _________________________
Subject: Re: Re[2]: Back on the road again!! [distributor timing]
Author: Ronnie Day <ronday@home.com>
Date: 5/22/2000 7:00 PM
>When Stephan told me he installed domed pistons I asked the same question
>with raised eyebrows. When we started her up, it didn't blow apart and we
>didn't hear any noise so it must be clearing the valves! His cylinders are
>20-over bored so the compression isn't as high as it could be.
If the engine has been bored, without a corresponding increase in chamber
volume, then that increases the CR since you're increasing the swept area
in the cylinder. In other words you're stuffing more cylinder volume into
the same chamber, so the CR is higher.
That's why we tend to be careful when putting L-series heads on Z-22/24
blocks. Chamber shape, cam overlap and other factors can have a big
effect on the effective, as opposed to static, CR, and also on the
tendency of a motor to ping and detonate.
FWIW,
Ron
Ronnie Day
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Dallas/Ft. Worth
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'71 510 2-dr (Prepared Class Autocrosser)
'73 510 2-dr (Street Toy)
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