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Re: cam timing

To: "Triumph Guys" <triumphs@Autox.Team.Net>, "Matt Barre" <mbarre@juno.com>
Subject: Re: cam timing
From: "Nick" <Nickbk@worldnet.att.net>
Date: Tue, 8 Apr 1997 16:02:42 -0700
Matt sez-

.<<  Part of the problem was the way I was checking the .050
tappet lift - at the valve and spinning the pushrod.  After finding
excessive duration I realized we had no taken the 1.5 ratio of the
rocker into account.  That made things better but I can't say that I am
100% confident we got it dead on.  It is definitely much much closer,
probably within a degree or 3.  I think I will leave the snout off till
I have a chance to run it around a bit and if I have to retime again I will
use a dial indicator and maybe have one of the tools described in the
comp manual to better check tappet lift.>>

Matt-
I see a problem loomin up in your future...
If you do not have a decent dial indicator and magnetic base, go get one
now, your hair will appreciate it (mine never likes it when I start pulling
it out in great clumps when the frustration
sets in). First thing ya gotta do is to check the tdc hole in the pulley to
make sure its close. With the head on its a little tougher, but not
impossible. There are better ways to do this, and this  may be a little
"down & dirty" but will work. Find an old spark plug and weld about a one
inch bolt to the inner end of it (don't screw up the threads). With the
motor approaching TDC (1/4 turn to go, or so), insert the plug into no 1
cyl and SLOWLY bring it up toward TDC. When the piston hits the plug, note
the distance from the pointer to the hole (a divider works well here). Now
remove the plug and move the piston past TDC. Reinstall the plug and turn
the crank back the other way until the piston again hits the plug. Again
note the distance from the pointer to the hole. The distance should be the
same on both sides. (am I the only one who ever reassembled the inner crank
pulley one bolt out of sequence ?)

DO NOT TAKE ANY READINGS FROM THE VALVE OR ROCKER.
There aren't any two production rockers that are the same, and none of them
will be exactly 1.5 ratio. Pull the rocker assy and use a pushrod held in
place by your dial indicator to do all your checking and degreeing. Check
both opening and closing on both intake and exhaust. (For all you retentive
type, like myself, you should check all of the lobes. You can't ever tell
when the grinder had to go get a haircut ...or whatever, and grind one
wrong. You will find that the cam will not match the specs, so get it as
close as you can. (If in doubt, I always go a little advanced as the
wearing chain will retard it as you go)

Take your time and when it starts to get weird, leave it alone til
tomorrow...
      Nick in Nor Cal

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