Do you have a shop compressor? if you do, use a compression hose, from a
good comp gauge to put air pressure in that cyl. then listen for air it
excape some were! if out exh. then exh. valve.
if out carb, then intake valve.
if in pan. bad ring.
any questions ? E-me off line
Greg in Fla
-----Original Message-----
From: Michael Lubitz <mlrba@texas.net>
To: Old chevy truck advice <oletrucks@autox.team.net>
Cc: Robert Lewis <rlewis@sss.austin.tx.us>; W&D <haist2@home.com>; W&D
<haist@jps.net>; Bob Adler <Advdesign1@aol.com>
Date: Monday, February 05, 2001 1:07 PM
Subject: [oletrucks] My head, oh my aching head
>Guys,
>
>I need help. A while back I was having a problem with hard starting, etc.
>with the 216 in the '46. It was diagnosed by the group as many things:
>carburetor icing, low compression, etc. So I rebuilt the carb, and the
fuel
>pump, and fixed the heat riser. No luck.
>
>Checked compression: Dry: 98, 90, 95, 45, 95, 90. Uh oh, number 4 is real
>low. So we did a wet test on number 4 and the compression did not change.
>O.K., need to do a valve job. When we took the head off, it was obvious
that
>the exhaust for number 4 was burned - badly burned.
>
>Now I asked you guys again about hardened seats, valve guides, doing all of
>the valves or just doing number 4, etc. Again, good advice - go the whole
>way.
>
>I did. $400 worth of new valves, seats, guides, lapping, surfacing, etc.
The
>head looked beautiful. We then put it all back together with new paint and
>cleaning everything in sight and torqueing the head bolts to 85 pounds and
you
>name it, we did it. Clean and nice.
>
>We went to start the beast yesterday and Buddy (the truck's name) had the
same
>problem as we had at first - hard starting and he would not stay running.
>Good fuel, good spark, adjusted the valves loose (Did the preliminary valve
>adjustment with the deaf man from across the street who used to work on old
>Chevies. He is probably 70 now. It was fun!)
>
>So we checked compression again. Dry: 50, 75, 55, 50, 50, 55. Yikes.
>Somewhat depressed, we did a wet test on number 4 and it did not change a
>bit.
>
>So, now it gets to be Sunday night. We called our truck club's resident
>expert. (He knows engines, he just knows engines.) No real answers.
Checked
>my doubts: Surface rust on the cylinder walls - no problem. Cleaning the
tops
>of the pistons with a wire brush and possibly scarring the cylinder walls -
no
>problem (of course, the wet test would have showed that.) Valves set
loose -
>no problem.
>
>The only thing that we can think of is that the valve job is bad. I asked
the
>guys who did the work when they were doing the valve job about being sure
that
>their work is done correctly. They said that they check each of the valves
by
>pulling a vacuum on the intake port (I don't know the word here, but it's
the
>about 1 1./2" round hole that connects to the manifold) and also by pulling
a
>vacuum on the exhaust port. And again, I do not know the word for the
>rectangular hole that the exhaust exits to the exhaust manifold.)
>
>HELP. Any thoughts from you guys? Know that I am sad but up to the
>challenge. Just want to do things right and get my Buddy back. I miss him
>and feel when he is hurting.
>
>Thanks to all of you for the help in the past and for help now. This is
the
>great group of guys (or of mostly guys).
>
>Michael Lubitz
>1946 Chevy 3/4 ton, stock
>1948 Chevrolet 3100, hot rod
>Austin, Texas
>oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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