Building a Small Block Chevy: 1985, 305
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The goal here is to detail the steps involved in assembling an engine. It isn't really necessary to have a lot of expensive tools, however it is imperative that you have a 3/8 and a 1/2 inch torque wrench along with a basic set of hand tools and a clean area to work. A shop manual for engine specs is also useful.
Our subject is a 1985 Chevrolet 305 engine in a 1/2 ton van. It came in to our shop with a rather loud rod knock. Upon disassembly we found that the number 4 connecting rod and corresponding crankshaft journal were damaged beyond repair. In fact the crankshaft took such a beating that it cracked and the connecting rod was egg shaped to the point where it's cap had to be forcibly removed. If this vehicle had been driven just a short while longer, that connecting rod would surely have exited the engine in a hasty manner destroying the cylinder block in the process. We got to it just in time.
Very simply the cause of this engine's failure was the dreaded "Sludgeus Buildupus". This customer (who shall remain nameless) must have been on the 12 month 12,000 mile oil change schedule. Every internal bolt was covered by inches of sludge that had to be dug out and disposed of before we could get it apart. I wish I would have taken pictures of the engine with the oil pan off, we could have used them in an oil change ad.
The block has been Bored and Honed .030 oversize.
We have a remanufactured crankshaft .010/.010 undersize.
The heads received new valve guides, springs, 3 angle valve job and were surfaced.
At this point I have what we call a finish cleaned block. This is a procedure that is done after all machine work has been completed. It consists of stoning all flat surfaces to remove any gasket debris and burs, brushing all oil galleries and bolt holes, a final run in our jet clean machine and a thorough rinsing and compressed air drying. All Oil galleries and bolt holes need to be blown out a couple times to thoroughly dry them otherwise some rusting will occur. The cylinders also need to be oiled rather quickly to keep them from rusting as well.
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