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Re: stiffer valve springs
In a message dated 95-12-30 09:50:48 EST, you write:
> BUT - is it a good idea? I don't think so. Especially just done
> by itself; done with a much hotter cam that needs stiffer springs
> might be another story. Reasons why I don't think so:
> a) stiffer springs will cause greater wear on the cam lobes
> and lifters.
> b) as long as you can rev to whatever your redline is, and
> don't get valve float or hydraulic lifter pump up, then
> the stiffer springs won't do a thing for you.
> c) If ya accidently rev it past the redline, stiffer springs
> will probably keep the valves working to whatever higher
> rev point where something else breaks ... rod bearings
And you don't rebuild the bottom end of the turbo cars, you replace the whole
thing, and with two of us working the tally was about 35hours labor
> d) if this is a turbo engine, there are tons of things you want
> to do before you even consider a higher rev limit.
>Here's some open questions for everybody -
> what did the factory use for a rev limit on their hotrods?
Well most of them used the mechanical cam, so not sure apples to apples
here..... Most had a 72-7500 cut out.......
> what gives up first when you consistently rev it past what point?
Mechanical cam will spit the shims....... Hydraulic will tend to float in a
big way, some cylinder wash, some rod bearing prolllums, then no oil pressure
> what's the RPM range and red line on the Schrick cam grind?
Which one, they make a 268, 272, and 276 app for the turbo cars, and I know a
few folks with 300 cams (abt), the Schrick folks leave the revs the
same....... I have the 272 with one tooth advance, and it comes on by 3k
and runs to a 7k cutoff (no cam adv it comes on BIG at 4200 to redline)......
Increasing the rev limiter is a dangerous endeavor...... Do it based on
research; not just thinkin, cuz chances are, the tradeoffs to that extra
500rpm is not worth the sacrifice to the audi gods....... Get into a lot of
available mods everywhere else before you start tweeking the rev limiter,
your wallet will thank you....