Mike,
Last week I was talking about head rebuilding with an experienced MG
mechanic. He says that since going the "no-lead head" route, he's
experienced this several times. When using the silicon/bronze guides, the
stock stem to guide clearance may not be enough to prevent seizure. I don't
know if this is due to vast differences in the coefficients of thermal
expansion between the steel valve and the bronze guide, or is a lubrication
problem. He says the solution that works is to ream the guides to .002"
oversize (You might check this number out-I'm no longer trusting my memory
like I once could...).
Good luck.
Jim Faulkner
Los Alamos, NM
Date: Mon, 20 Jul 1998 09:47:02 -0400
From: "Mike Brinker" <Mike.Brinker@mfasco.com>
Subject: Stuck Valves
After doing my initial Run In on my TR6 motor, it began to run extremely
rough with some back firing. When I removed my valve cover I notices 3 of
the valves were stuck open (in the down position). why would this happen
and what is the cause? I have a newly rebuilt head with all new valves and
guides. Oil pressure is good 85 - 90 lbs and I primed primed the engine
with oil before my first time start up. I used a special tool that allowed
me to turn the oil pump and circulate oil through the entire engine without
moving a piston or moving a valve. Now it seems I have to pull off the head
and take it back to the machine shop. Any ideas why this happened? What
will prevent this from happening again!
Mike
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