Rod knock resulting end cap coloring. Reusable? 3.0

[lr3guyjoe]

Bought a project with a blown head gasket. Got it all fixed and back together. At idle all sounded fine and oil pressure was in the 40s.

Took it out for a test run and there was a bit of clatter and at first thought valves might need a bit of adjusting. But when I got in to higher rpm it got worse and then oil pressure started tanking. I got off the power and idled it back to the dock.

Pulled the motor and the found the number 4 rod was the culprit. Pulled the crank and took it to the machine shop, they verified its not bent and they are going to do the mains at .010 and rod journals at .020.

My question is.. there was discoloration on the number 4 rod cap. Is there any issue reusing the rod and cap? I really don't want to tear the top end apart again in order to pull the piston.

 

[Scott Danforth]

What does your machine shop say?

Personally, if there is discoloration, most likely the bearing spun. If the bearing spun, the rod is questionable

 

[HT32BSX115]

My question is.. there was discoloration on the number 4 rod cap. Is there any issue reusing the rod and cap? I really don't want to tear the top end apart again in order to pull the piston.

I would be asking the machine shop about re-sizing the rods and re-using one that was overheated after a possibly spun bearing! Rods aren't all that expensive. (but can be when one breaks!!)

 

[fishrdan]

No question about it. I would pull the head, so you can take the rods/pistons down to the machine shop for inspection and resizing if needed. Especially since a bearing spun. You're having the crank turned, and it would be a shame to tear up the rebuilt crank with a bad rod.

 

[lr3guyjoe]

The bearing actually wasn’t spun. The cap side was badly worn and the rod side was “smushed” at the top. The little retaining tabs were still intact.

The photo is of the rod side bearing. The other bearing is the one from the 3rd cylinder.

Ill send end a photo of the rod cap the weekend, currently traveling. Machine shop said I’d have to bring the rod in. Is it just a matter of checking to see if the hole is still round?

 

[lr3guyjoe]

I know I’ll probaly end up needing to pull it... just really really don’t want to. I have an oem from the local boat store $70 head gasket on it, just depressing to destroy..

 

[Scott06]

Something is not right with that bearing end or crank journal. Just bite the butler tear it down and have it measured up and resized if needed