Re[2]: pistons & valve lift

[Richard Welty <rwelty@xxxxxxxxxxxxxxx>]

On Thu, 05 Jun 2003 11:46:42 -0400 Andy Kress <aokress@domain.elided> wrote:

> I don't know the exact limits of FP limited prep rules so I don;t know
> how 
> much you can modify - head thickness, pistons (do they have to be an OEM 
> offering?) can pistons go to .040" over?.

well, it's one of those things. there's a fairly wide open set of rules for
engine prep.

in limited prep, a set of restrictions are imposed for each individually
classed car. i'm using the existing set of restrictions for the
2002/320/318 as they are cars from the same era and displacement.

> if cam timing, 
> duration and overlap are left wide open - then dynamic compression
> ratios 
> will vary widely w/ the cams selected- the more static compression you
> can 
> get (or more precisely, be allowed to chose from) the better.

in a typical limited prep engine, there are no restrictions on cams
other than lift that i can see.

>  If you
> can 
> go aftermarket and use .040" over pistons - Paul Spruell sells an 85mm 
> forged piston that can be ordered in an 11:1 ratio.  I believe there is 
> enough metal on top that some could be shaved off if you end up needing
> to 
> come in under 11:1.  I'd ask for as much as you think you can get from
> them 
> - more.

i think we could get 10.5:1. 11:1 might be a stretch. we'll have to see.
0.040" over is definitely legal, though.

thanks for the info.

richard
--
Richard Welty                                         rwelty@domain.elided
Averill Park Networking                                         518-573-7592
              Unix, Linux, IP Network Engineering, Security
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