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Old 04-05-2016   #12
tpepmeie
 
Join Date: Aug 2005
Location: Fishers, IN
Posts: 812
Default Re: Intake runner length

Quote:
Originally Posted by Hib Halverson View Post
I get it.

To get a bit off topic here, my belief, admittedly based pm old information from road racing in the late 90s, is that the cam drive mechanism in the LT5 is not very reliable above 7200 or so when using high-lift cams and appropriate greater pressure. Your thoughts?

The chain drive configuration is not a problem, many highly successful Cosworth F1 and Indy engines used chain drive. What I have gathered, probably from yourself, Graham, and others is that the cam sprockets were intentionally made small to keep the overall engine width small enough to fit between the frame rails from the bottom. The consequence is that there is less chain "wrap" than you'd like for a high rpm engine. This inevitably stresses the chains more.

Solution? Higher strength cam chains. Jerry and I worked with IWIS to get some HD chains made last year.

Of more concern for high rpm operation, to me, is the lubrication and windage control. Too much crankcase pressure and the oil won't evacuate the top end well enough. I've already seen more positive crankcase pressure than I'd like at 7000 rpm. Dry sump would be ideal, but plumbing is nightmarish.

as always, YMMV.
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