Dumbo The Flying Elephant

[Larry Hill]

Cold. it turned over to easy

[Larry Hill]

Back to Dumbo. On further tear down the pull down side of the crankpin needs to look just a little better. The bearings look great only one spot to look at and figure out why.

[Larry Hill]

Now I have two spots on two different rods but the spots are in the same place, at the parting line where the wash, may not be the correct terminology, area is on the bearings. I found no sign of trash, burrs, or whiteness marks on rod i d or shell. CB663HXN

[pmrphil]

Do the marks correspond with either end of the bolt? How far from the parting line are they?

[Larry Hill]

The the damage spots are on the upper bearing shell at the part line on the chamfered side of the rod. I got a double ball micrometer and checked thickness at the edge opposite the tang and the thickness change was.0018” in the width of .785”. Vertical clearance is fine, it just about a .125”wide spot that is protruding into the ID of the rod clearance area that is being removed mechanically exposing the steel bearing shell to the crankshaft

[Larry Hill]

Ordered a new set of bearings so maybe I can make a good set out of two sets that I will have. Also have a set of AOL coming to look at and see what kind of clearance we will have.
Another shop kind enough to let me use their double ball micrometer to check my bearings. Wednesday I will have my own ball micrometer.

My old drag racing advisor Richard Carter said “If you have to borrow something more than once, you need to get one”

[Larry Hill]

I'm lucky enough to be able to call an engine professional and get their advice on how to proceed. The new ACL race bearings did pass our new incoming QC test for edge variance. I still have to check for clearance and weight difference for balance. The ACL parts a just a little bit wider than the CB663's.