[MV] FYI: Chev HMVs

James Burrill (jburrill@dttus.com)
09 Sep 1999 11:47:07 -0500

Hi List,

Just learned something and wanted to share it.

I am swaping a WWII 216 straight six for a 54 235 straight six to get
better oil flow and a little boost in performance. For the most part,
the block looks the same and to the average veiwer, their isn't much
external difference. I want it to survive driving to local events
rather than trailer it and be 100 % authentic and have to trailer it.

OK, the problem I run into is the bearing that goes in the end of the
crankshaft. I pulled out the pin roller bearing from the old motor,
but it wouldn't fit in the hole in the 235. I had always been told the
parts were interchangable. In any case, I was ordering the bearing for
a 54 235 crank anyway, not the 216.

The replacement part (verified by both the counter man and the parts
house owner) was too big to fit. Way to big to "tap it in place". The
later 235s used a solid bushing instead of a roller bearing. I bought
that also but, although close, was too big to put in.

At this point I was going nuts trying to figure what was off.

An older neighbor dropped by and in the conversation he told me what
was up. Cranks used in straight shift vehicles had the whole machined
out to fit the bearing. The same crankshaft earmarked for an automatic
transmission (powerglide) was not machined out as it was going to have
a torque convertor bolted to the crank. The whole that is there,
however, was only there for spinning the crank as part of the
machining process for the crank bearing faces.

Now it seems the books at the parts house didn't point out the
differance. And none of the staff (all 40+ in age) knew the
differance.

My neighbor happens to run a machine shop at his house so he came and
miked the hole and will reduce the solid bushing to fit. Trying to
re-drill the crank was ruled out, as it would add a lot of time (plus
taking the engine apart again) to find a shop that could brace the
crank and garantee a true bore to enlarge the whole.

So, my fellow Chev owners, if you upgrade to a newer, straight six
motor, be aware of the difference between getting a motor from an
automatic configured truck.

Cheers!
Jim (Thankful he has a machine shop owner as a good neighbor!)

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