[6pack] Valve lash question

[Vance Navarrette]

	Matt:

	It may be recession, although it is also possible that you set the
lash too tight in the first place. I have certainly set them too tight on
more than one occasion.

	The exhaust valves are the ones that will recede as the heat makes
the valve seats erode. I would reset the lash, double check it, and then
periodically remeasure it to see if it tightens up again. If it does, it may
be time to pull the head and have hardened seats installed. Drat.

	Have you read your plugs? Was the mixture lean? Lean mixtures will
really make the seats recede as the high temperature takes its toll. So
reset the mixture if your plugs are light colored or white.

	Vance

-----Original Message-----
From: 6pack-bounces at autox.team.net [mailto:6pack-bounces at autox.team.net] On
Behalf Of mjmullin at juno.com
Sent: Tuesday, January 18, 2011 3:13 PM
To: 6pack at autox.team.net
Subject: [6pack] Valve lash question

Hi all: I too prefer the list.  If I could surf the net all day at work, I'd
likely be a more frequent visitor to the forums!!! Problem/topic for
discussion:  I was setting my valve lash yesterday (after five or ten
years?)
and would have thought the clearances would have remained rock solid all
these
years, but to my surprise, most of the valves loosened up a little - I guess
it's wear in the valve train, cam, lifters, etc.  More surprisingly, two of
the exhaust valves (#5 and #9, fed by different carbs) had closed up.  It's
a
Ted Schumacher 275 cam that's supposed to have .020" hot on the exhausts;
one
had gone down to .010' and the other to .006" cold.  Wow. Valve seat
recession?  

<snip>

Matt Mullin