Found Rod Knock

Fri Oct 21, 2005 1:07 pm

It appears my knock is the wrist pin or bushing. Removed bearing cap and rod bearings look perfectly new. Pushed piston on up into bore and I could rock rod for/aft about 15-20 degrees along with noticeable up and down play without piston moving.Rod also has noticeable twisting motion. I assume it should only rotate about the pin without any play otherwise. I'm guessing the short block builder messed up in this area. I bought the block out of a tractor that was built for pulling and had only pulled a couple of times when the owner decided it wasn't powerful enough to compete. Oh well I'm a learning :lol: :lol: Someone once told me education can be expensive. This one should be more time than expense I hope.

Fri Oct 21, 2005 8:41 pm

Glad to hear it's not a blown crankshaft.

Thu Oct 27, 2005 5:34 pm

Well I got everything apart and inspected and I gotta say this one was text book all the way. The rod bushing came loose and was allowed to rotate thus the oil hole no longer lined up with the hole in the rod. Loss of lubricant lead to advance wear condition in the bushing.
I was diligant enough to get this one before something bad happened. I would advise anyone with a noise no matter how insignificant to check it out. Just as in my case a little tick turned out to be a serious problem and if left alone could have lead to engine failure eventually. The kit installed was a Tisco. The pistons have a rather large piston pin that requires a thin bushing rather than the thick one that may have been stock. Anyone doing a rebuild would be wise to pay close attention to this area. The rods are now at a shop where they might have to rebore the rod and install oversize bushings.
That little tick just might be something more! :wink:

Sat Oct 29, 2005 8:09 pm

Glad that is all Bill. As bad as this seems it is better than if it had been a crank gone bad.
Glad you caught it in time.