The outside surfaces
The first thing I look at is the front of the case. Lots of stuff to check over there. The first of which is the area just adjacent to cylinder #3.
The above 2 photos are of my old SOPR case which has about a 6" - 7" crack which originated between the main webs and grew about 1" past both main webs (OUCH!!). Look VERY closely. You don't want to miss a crack here. If you do, you will own an ex$pen$ive door stop. If ANY cracks are found, kindly inform the owner that the case is junk and walk away.
Above is a photo of a GOOD area behind #3 cylinder. Note the absence of any cracking where the pointer is. Also check the main webs on either side. If the case looks like this, so far, so good and continue the inspection. . .
Above are 2 photos of the front (or main) engine seal area. The LEFT photo is of a chewed up seal seating area. This kind of damage typically happens when the flywheel comes loose and bangs (chews) it up. An engine would probably leak oil from here from the poor seating of the main seal and soak that new clutch plate with oil (BAD; very bad). The RIGHT photo shows a good sealing area. If the case you're looking at looks like the RIGHT photo, so far, so good and continue the inspection.
Next check out the cylinder seating areas. Loose head bolts allow the heads and cylinders to move around. This will cause an indentation (pounding) of the cylinder seating area. You ideally want this area to be free from grooves going around. You can have a case machined to correct this pounding but it will add around $40 to your machining bill. Figure this cost into your offer if everything else checks out. It's called "spot-facing" the case. They basically will machine the raised area down flat with the lowest point. This machining WILL effect deck-height and cylinder shims WILL BE REQUIRED upon reassembly.
The above photo is of some minor damage caused by allowing the rods to rest on the cylinder bores while the crank was rotated. Never turn an engine with the rods hanging unless you wrap them in a rag or something soft.. Ensure there are not large burrs or high spots which could cause the cylinders to not seat flat when assembled. This damage is irrelevant if you are planning to have the case bored out for larger cylinders. Again, spot-facing will correct really bad damage.
Look at all of the case savers (if installed). Make sure none are missing, damaged or pulled out.
After that, just give the rest of the outside a good close look. If you see anything that doesn't look quite right, question it; ask for an independent, second opinion; compare it to a different case, etc.
So how does the perspective case rate so far?? Now let's pull the two halves apart and get a good look inside. . .
Copyright © 2000 - present AircooledTech.com. All rights reserved.
Revised: August 29, 2003
.
