by David Easterwood
I found a person with a used short block for sale
for $75.00. Can someone give me some pointers on
what to check for to make sure the case is re-buildable?
Well, you can't tell while it is a shortblock, so tear it down first.
When you get it apart, inspect the main & rod bearings to see what kind of life the engine led. Are there any wear marks on the bearing surfaces that indicate it was run with dirty oil? Any blueing of the main or rod journals on the crank to indicate it was run hot?
As for the case itself, the first thing I inspect is the area of the oil sump. Is there any metal deterioration there? If so there was water in the case for a while, or it sat with old oil in it for 5 years or more.
The next area I inspect is the the main thrust bearing dowel pin hole. I think this area is often overlooked. If the dowel pin has any movement in the hole I trash the case. The movement means the end play was not set correctly and the excessive end play caused the dowel pin to oval out the hole.
If it still checks out, then I thoroughly clean the case with a pressure washer. To do it right you get *soaked*! ;) Make sure you clean out all of the oil passages. Then I blow the case out with compressed air to dry everything.
Then I bolt the case back together and torque to spec and shine a light in the case to make sure the case halves seat together correctly & the case has not been overheated & warped.
After that I look at the main bearing saddles. If you can run your fingernail over the saddle and feel a ridge where the oil passage for the bearing was, then it definitely needs an align bore. I then check with new main thrust bearings to see if it is a standard or cut case and see if the thrust needs to be cut on the case. (you have 3-4 sets of new bearings lying around, don't you?)
If the case passes all these tests, sometimes I take a torch & heat up areas above & in front of the #3 spigot to see if there are any hairline cracks.
These are a few things I do before I send a case out to be machined. I
probably forgot a thing or two...