connecting rod on wrong way..big deal?

[75-JOHNSON]

just took apart my 1976 75hp johnson to change a broken ring and i noticed the connecting rod is on upsode down. the oil hole in it is facing down, not up. i beleive the motor has run like this for some time and the bearing on the wrist appears to be alright. i tried pushing out the wrist pin to put the connecting rod on the right way but its to difficult for me and i dont want to break the piston. do u thing the wrist pin bearing will stay lubricated enough as is?

 

[14ftgrumman]

Re: connecting rod on wrong way..big deal?

How did you determine that the rod was on wrong? By service manual, or by comparing it to the other rods in the motor?

But, yes. It would be a big deal.
Who had the engine apart before you? And how long ago?

 

[petryshyn]

Re: connecting rod on wrong way..big deal?

Worked on a 3 cylinder reconditioned by OMC. Found the top rod upside down. It had run for 15 years with no bearing failure.....The only reason I pulled it down was to replace scoured pistons from overheat.

 

[75-JOHNSON]

Re: connecting rod on wrong way..big deal?

How did you determine that the rod was on wrong? By service manual, or by comparing it to the other rods in the motor?

But, yes. It would be a big deal.
Who had the engine apart before you? And how long ago?

according to the service manual it is wrong. before me i beleive it was a dealership that had it apart, not entirely sure though. that was back in the 80's and it has been used very little since then.

 

[Joe Reeves]

Re: connecting rod on wrong way..big deal?

The hole in the rod must face upwards to provide proper lubrication. Unfortunately, back then, the wrist pins were a pressed fit, not floating pins.

You can correct the error by securing the rod/piston upright in a vice, remove the wrist pin retaining snap rings, heat the piston somewhat with a hand held propane torch with a blow torch tip, then tap the wrist pin in/out to a point whereas the piston can be lifted and reversed on the rod.

Notice the underside of the piston in the wrist pin areas. Normally one side is marked indicating the tighter side. Tap on that side.... once the wrist pin clears, it moves fairly easy.

 

[F_R]

Re: connecting rod on wrong way..big deal?

The hole in the rod must face upwards to provide proper lubrication. Unfortunately, back then, the wrist pins were a pressed fit, not floating pins.

You can correct the error by securing the rod/piston upright in a vice, remove the wrist pin retaining snap rings, heat the piston somewhat with a hand held propane torch with a blow torch tip, then tap the wrist pin in/out to a point whereas the piston can be lifted and reversed on the rod.

Notice the underside of the piston in the wrist pin areas. Normally one side is marked indicating the tighter side. Tap on that side.... once the wrist pin clears, it moves fairly easy.

I almost challenged this advice, but Joe is right in what he said. If doing it with the rod in a vice, he is correct. However, if you are removing the pin by using a press, it has to be pressed all the way out through the tight side, and reinstalled going in the loose side till seated properly in the tight side. (Loose side is always "up" in the press). To do it backwards will collapse the piston.

 

[Joe Reeves]

Re: connecting rod on wrong way..big deal?

Yep..... I figured that he didn't have a press or piston cradle handy.

 

[1946Zephyr]

Re: connecting rod on wrong way..big deal?

I had a rubber piston cradle when I replaced pistons and put the tight side down and drove the pins out the bottom.

 

[75-JOHNSON]

Re: connecting rod on wrong way..big deal?

tried heating up the piston and still had trouble. i figure for the small amount im going to use this boat ill just leave it the way it is and not risk breaking anything.

 

[daselbee]

Re: connecting rod on wrong way..big deal?

tried heating up the piston and still had trouble. i figure for the small amount im going to use this boat ill just leave it the way it is and not risk breaking anything.

You are on this site for advice. So, I just gotta say that I think it is a bad decision to leave it installed wrong. For a very small fee, I bet a machine shop would turn that piston around for you. It will be cheaper than replacing the powerhead later because the rod went thru the side of the block.

 

[Joe Reeves]

Re: connecting rod on wrong way..big deal?

In agreement with Daselbee.

 

[75-JOHNSON]

Re: connecting rod on wrong way..big deal?

thanks for the input guys, decided to go ahead and change it around and by putting the piston in boiling water it made it easier to get tyhe wrist pin out.