On Mon, 13 Oct 1997 21:51:21 -0500 "Tyson Sherman" <tsherman@tecinfo.com>
writes:
>..... I slacken the nut and slacken the screw, but the valve moves open
(there was no clearance anyway). ..... How do I get clearance on valve
#1 .....
If you have the adjuster screw backed up all the way and you still don't
have enough clearance, you either have a broken valve head or valve
recession. If it ran half decent before your fiddling, it probably isn't
a broken valve. Valve recession is when the valve gets burned or worn
and/or the valve seat gets burned or worn so the valve head sits deeper
into the seat and the stem protrudes more on top taking up the clearance
at the adjuster screw.
The proper fix for valve recession is to remove the cylinder head, have
the valve seat machined out of the head, and have a valve seat insert
installed to renew the material. If you're going to all that trouble,
you will be getting a fresh valve job at the same time. And while you're
at it, it's a good time to get that no-lead head job done. This includes
the installation of all new hardened steel valve seats, possibly bronze
valve guides, and maybe even stellite exhaust valves.
In the mean time, assuming that you don't want all that bother and
expense just now, you can do a "Grapes of Wrath" fix for the moment.
>From the front of the rocker shaft, remove the split pin, flat washer,
coil washer, and #1 rocker arm. Using a hand grinder (or emery paper on
a sanding disk with electric drill), remove a little material from the
end of the valve stem. Be careful of course not to let the metal
particles fall into the engine, and try to keep the tip surface flat and
perpendicular to the stem. Replace the parts and adjust the running
clearance as normal.
The last time I did that, it lasted until the head needed to be replaced
for some other reason and saved me a lot of money.
Barney Gaylord
1959 MGA with an attitude
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