> Date: Mon, 11 Nov 1996 15:40:22 -0600
> From: William Eastman <william.eastman@medtronic.com>
> To: mgs@autox.team.net
> Subject: Camshaft vs valve lift.
> Reply-to: William Eastman <william.eastman@medtronic.com>
> Most cams are advertised by valve lift and total duration. There is no way
> that I know of to measure duration without putting the cam in the car and
> measuring with a degree wheel. Maybe you could do it out of the car but I
> doubt is since the exact position of the lifter is crucial to when it
> starts moving. Also, any degree information taken directly from the cam
> would have to be doubled since it spins half as fast as the crank.
Best way I know of to measure the duration out of the car is to mount
the cam on something it can rotate in (like a couple of boards with
Vees cut in them) then put a dial indicator on the flat side of a
given lobe, zero it, then turn the cam until the indicator starts
moving again. Mark it, continue turning until the indicator gets to
the previous reading... and viola. Of course the easiest way would
be to have a degree wheel on the end, but I suppose you could get a
rough measurement with a protractor.
This pretty much the same procedure as "degreeing" a cam in the car.
I think I read it in one of Marc Sayer's articles in MG MAgazine a
long time ago...
-Rick Guynn
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