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Re: [oletrucks] Need GMC 270 overhaul advice...

To: 59gmc@bigriverbroadcasting.com, oletrucks@autox.team.net
Subject: Re: [oletrucks] Need GMC 270 overhaul advice...
From: JohnHuntD@aol.com
Date: Tue, 18 Mar 2003 11:11:20 EST
I've rebuilt half a dozen V8 engines over the last 40 years, and probably 
like most self-taught shade tree mechanics, learned by trial and (lots of) 
error. If you've never done a complete engine overhaul before my 
recommendation is that you do what I now do, which is as follows:

1) Take the engine (either complete or torn down by yourself if you feel 
inclined) to a reputable engine rebuilder.

2) Have him boil the block, crank, and head to get all the old sludge and 
other 40-year-old gunk properly cleaned out

3) Have him inspect all the parts including the crankshaft, rods, camshaft, 
pistons, cylinder walls, main bearing saddles, etc. and tell you what needs 
to be done and what needs to be remachined or replaced.

4) Have him do the necessary machine work such as grinding or polishing the 
crankshaft journals, align-boring the block if the journal saddles are not 
true, truing the rod ends, etc.

5) Have him assemble the short block with new main, rod, and camshaft 
bearings, which should insure you have the all-important correct rod and main 
bearing clearances. Also it is easy to ding the cam bearings when 
re-installing the camshaft if you have never installed a camshaft before and 
don't know how to properly hold it during installation. 

6) Have him do the head work of grinding or replacing as necessary the 
valves, inserting new valves guides and  hardened valve seats, and reassemble 
with new seals and valve springs.

7) Have him install the head and torque it down properly. 

8) Bring the engine home and have fun installing the manifolds, distributors, 
alternator or generator, bolting it to the flywheel, clutch and transmission, 
and re-installing it in your truck.

Yes, you can teach yourself how to do the complete engine rebuild and learn 
as you go, but unless you specifically want to do that I lean toward having 
the "long block" done by a trusted pro. That way I have no worries about 
critical internal engine parts self-destructing as I motor happily down the 
highway 100 miles from home.

Hope this helps, and please remember this is just one man's opinion.

John Doak in Baltimore, MD
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959

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