This weekend Brian from the Orange County Beater's Club came up to my
shop with his stunning '55 second 3600 and together we opened up the bottom
end on my used 235. The visible exterior portions of the motor had shown
ample evidence of a very low quality of work and I had hopes that perhaps the
lower end would have been a professionally done "short block" and out tyro
mechanic would not have worked his mayhem within.
What we found inside has so far not been encouraging. First the pan
had several missing bolts. The timing cover proved to have three missing
screws, two of which we broken off in the block. It also has an ovaled hole
here and there and is somewhat beat up, signs of a great struggle by somebody
in the past.
Our past mechanic had tried to reuse the lockplate designed to hold
the two capscrews into the front main cap and the retaining corners had all
broken off. They may well have been part of the mucho particulate debris
laying throughout the interior of the crankcase chamber.
I didn't inspect the entirety of the camshaft, but one portion, the
fuel pump lobe, had a concave wear pattern and did not look promising.
We removed the main bearing caps and had a look at the bearings using
the green plasigage. The number 4 main looked reasonably good with .0025
tapering to .001 at the rear of the bearing. The number 3 main insert looked
a little battered, but still was within spec at .003. The forward thrust
surface was just into the copper backing. The number two main looked even
more battered, gauged at a little over .003 (but less that .004) and the
insert showed some copper on it's sides. The front main was not inspected
because a broken bolt from the timing cover prevented it's removal. The rods
were not inspected due to an early call by the Boss to take her to dinner.
What I have seen so far looks marginal at best. My every instinct
says that this motor is worn and needs serious work. In this motor's favor,
it was running well when removed and probably has some life left in it. I
will have to take a look at the rods to see if they can break the decision
one way or the other.
Questions:
1. Can the cam gear be removed and replaced without removing the cam?
2. Is that concave wear pattern on the cam lobe mean this cam is not
usable?
3. Is there any necessary problem with the copper starting to show on
the inserts if the clearance is still within spec?
Paul O'Neil, Hudson29@aol.com
1951 Chevrolet 3600 Pickup Project, See it at:
The Poor Man's Advanced Design Tech Tips Page
http://home.earthlink.net/~conntest47/
Fullerton, California USA
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