Rod cap alignment: seat themselves?

[ct1762@gmail.com]

I've been pondering this question for a while and thought i'd see if anyone has thoughts on my little theory regarding connecting rod caps on 2 stroke outboards. I only rebuild OMC motors, and use the rod cap alignment tool when needed (NOT on the hand-sanded rods, of course), but this applies to any cracked rod, i suppose. My observations lead me to believe a large number of these rods have a seam or seams that can be just felt INSIDE the rod from the factory, as they are easy to get perfectly matched on the outside, but not always so on the inside. the manual just seems concerned with ligning up the outsides, and thus leads me to believe a small seam on the inside isnt a problem. Do you think the engines actually seat themselves after some running? after all, there are tens of thousands of PSI on the caps when running, and are only held toghether with 30 ft/lbs of torque. The bearing cages seem to provide some protection.I've put many motors toghether when feeling a tiny seam on the inside, but nothing on the outside and they are still running fine. with a stethoscope, i can never hear any weird noises when turning them over. what's the verdict here? getting brand new rods for each rebuild just isnt practical or affordable, either.

 

[Faztbullet]

The "cracked" rods are machined as one piece like a Yammy rod then broken. Yes there will be a seam but it should not be felt. Never use a rod that has had a piston failure. I always prep my rods by torqueing caps and use a flapper sanding wheel to polish inside of journal. I use old rod bolts to torque em with and have several bolts with slots cut in em to clean out threads.

 

[racerone]

Is there any load on the cap at full throttle ?

 

[ct1762@gmail.com]

interesting thanks. what grit flappers do you use? you just polish the seams or the whole radius? assume the whole radius just curious ill give it a shot. i have had many motors were there was no piston failure but rod seams felt the exact same as rods that were sitting on a blown piston. Good practice though ill try to stick to that. i guess the seams can be felt after taking the rod cap off a well used motor and need to be perfect.

 

[Faztbullet]

240 grit inside the radius..

 

[ct1762@gmail.com]

awesome thanks. i always thought there was some sort of nickel/metal coating on the inside to help keep bearing friction down. guess thats just wear?