Rod Cap loose?????!!!!

[jakestevens]

I'm assembling a 1975 mercury 2 stroke 650. I'm at the point where the piston/crankshaft assembly is in the block. I put my fingers around the piston rod end caps and they feel loose. The rod cap bolts are torqued to spec.
I used new needle bearings, but used the original cages. Anyone have any idea what kind of problem I'm looking at? Thanks a lot.

JS

 

[jakestevens]

Re: Rod Cap loose?????!!!!

Has anyone on this site rebuilt a 1972 to 1975 mercury 3cylinder?

 

[jakestevens]

Re: Rod Cap loose?????!!!!

OK..Can anyone give me an idea about clearances between the piston connecting rod and the crankshaft journal? Is it a loose clearance to compensate for heat(expansion)?

js

 

[Laddies]

Re: Rod Cap loose?????!!!!

You need to mike the rod and crank, heres the specs.

 

[jakestevens]

Re: Rod Cap loose?????!!!!

Thanks for the reply. I'll tear down the assembly and verify the specs. The connecting rod, connecting rod bearing cage, and crankshaft are the same one that was in the original assembly. I inspected the crankshaft after disassembly and there were on signs of heat or wear. Is it possible that there is that much wear on the crank that is not noticable? If so, is there an oversized bearing and bearing cage to compensate for the wear?

Thanks a lot for your help.

js

 

[Laddies]

Re: Rod Cap loose?????!!!!

Seldom does the crank wear but once in a while you will find a rod thats worn. The only fix is a different rod or crankshaft.