No chamber relief done on the head. I got the rods
resized but that should be insignificant in respect to
the piston/valve clearance. I don't know how much is
typically shaved off in this process.
When we got it started, the gas tank was pretty much
on empty and the fuel was 8 months old...
I did a quick compression check on one cylinder and
got 180psi.
--- Fred_Katz@ci.sf.ca.us wrote:
> 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
> 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
> ------------------
> Dallas/Ft. Worth
> ------------------
> '71 510 2-dr (Prepared Class Autocrosser)
> '73 510 2-dr (Street Toy)
>
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