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Re: Parts for cam replacement

To: dmeadow@juno.com
Subject: Re: Parts for cam replacement
From: Michael Taglieri <miket_nyc@juno.com>
Date: Fri, 16 Nov 2001 02:33:52 -0500
>Depending upon the lifters that you are taking out, they may also
>be the wrong length for the new ones, you'll have to check to make sure.

>I know of no reason why they should be replaced as a matter of course
>when you replace the cam, but maybe another lister will tell us.
>
>Remember, when starting the car for the first time run it at no less
than
>2500 rpm for at least 20 minutes.  This allows the cam to "run-in." 
>Generally speaking the lifters will wear in to conform to the lobe on
the
>cam.  Once you've run the motor you can't swap lifters around, nor can
>you use used lifters with another cam.  If you do, you risk premature
wear.

I'm a newbie on British cars, but on British motorcycles, you must
replace or at least resurface the lifter faces whenever you install a new
cam, because if the lifter doesn't press on the whole face of the camlobe
evenly, the pressure will be excessive on the part that touches first,
which will soon wear through the hardening.  Then the pressure will be
excessive on the part that touches next, and so on.  Since the old cam
and lifter wore to fit each other, there's no likelihood the old lifter
will fit a new cam.  

On large maker of British motorcycle cams also strongly recommends that
you coat the camlobes with machinist's bluing, assemble the barrel and
lifters to the cam, turn the cam through once, then disassemble and check
to make sure the bluing is swept evenly off the lobes.  Sometimes the
barrels, cam bushings, etc., were not machined correctly in the first
place and will wear out cams regularly for this reason.  Obviously this
would be much harder to do with a car engine but worth doing if possible,
and if you were determined to use unresurfaced lifters, this could also
give you an idea how well they fit the cam.

Finally, the same cam maker voids the warranty on the cam unless you use
new (not resurfaced) lifters.

Mike Taglieri - miket_nyc@juno.com

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