Connecting rod cap install

[kman61]

Hi, I am (attempting) rebuilding my '96 Erude 88 SPL. I am at the point of installing the rod caps over the crank bearings and am having a heck of a time getting the caps aligned with the rods such that the seam cannot be felt with a pencil tip / fingernail, especially on #3 for whatever reason. I would call them 'very close' and feel that some might consider good but I can still feel on some of the surfaces, usually one of the ground beveled sides. I obviously do not have the special assembly tool as called out in the service manual. As general info: I marked hole number & direction of all components and then individually tagged & bagged each during dssy. I verified that all rods were assembled into pistons and pistons into bore correctly. Factory 'dimples' on rod & cap match up on all. The splits visually line up but can still just can feel.
Does anyone know of a trick, tool that might help me here?

 

[gm280]

Re: Connecting rod cap install

I don't know what special tool you are referring to, but I'd take the cap off the one you are having a problem with and remove the cage and needle bearings from both side of the journal and reinstall the rod cap. Now see if you can feel any edge on the inside of the rod and cap joint. If so, you need to readjust the fit until it is smooth inside that joint. Then look at the outside rod cap joint and take notice if there is or isn't a difference there also and mentally remember what it looks like so when you reinstall the cage and needle bearings again and tighten the rod cap down it mimics the previous setup you confirmed was smooth inside. I mean after all it is the inside you are concerned with, not the other side. Too bad you can’t use plastic gage on needle bearing setups. It would prove they are fitting perfectly... If you have both side with a feelable edge, try adjusting them out and it you can't, posion the rod cap to minic the less amount of both sides. That is all you can do with cages and bearings like that. JMHO!

 

[kman61]

Re: Connecting rod cap install

The special tool is P/N 396749, 'OMC alignment tool' designed to get these caps perfectly aligned. After spending a total of 4-5 hours adjusting caps every which way, removing caps and bearings, trying a test fit (no bearings / crank journal), reassemble, etc. I'm convinced there is no way, no how this can be done 'perfectly' by hand. Perhaps my expectations are too high or my particular rod / caps assemblies are especially difficult due to their respective fracture patterns but I’m just about to the point where this thing’s going together as is.

 

[gm280]

Re: Connecting rod cap install

I've tried to locate a picture of this $500 dollar special tool to see what it looks like and maybe how it works. That cost is unbelievable and I don't think it is needed for your success. JMHO though! I've also read a few posts on other marine sites and they also think it is not needed as well. One person suggested installing the cage/bearings and then the cap on the crank and snug the cap tight. Then before tightening to torque specs, rotate the crank over about three or four times and then tighten the cap up and torque to spec. Everything will be correct according to their procedures. Not 100% sure, but I don’t think the cage(s) rotates around the crank/rod cap anyway, the needle bearings only rotate. And so the needle bearings would never have to cross the very slight mismatch fit of the rod and cap fit. So even a very slight edge on the alignment, the bearings will not have to cross such a joint alignment... Just an idea, but others seem to think that works correct...

 

[kman61]

Re: Connecting rod cap install

I found this old post that seems to describe my problem, which feels llike to me from the way my nail or the pencil catches, that the cap actually sprung open once disassembled. I am now going to try and measure both the rod & cap width (across both cap screw holes on ground surface) and see if I can learn something. Not sure if I'm ready to squeez the caps in the vise but maybe that's one funtion of the 'alignment tool'?

Thread: Evinrude Rod Cap alignment
Jan 9th, 2007

“…The caps are always wider than the main part of the rod.We spring them inward with soft (paperboard lined) jaws in a bench vise---very carefully until they fit with just an index finger holding the cap in place. Then assembly in the engine is easier and a sure bet!
I'm always inclined to give our assembly tool away, but, now and then we get a request for it's use by a customer.”

 

[gm280]

Re: Connecting rod cap install

I found this old post that seems to describe my problem, which feels llike to me from the way my nail or the pencil catches, that the cap actually sprung open once disassembled. I am now going to try and measure both the rod & cap width (across both cap screw holes on ground surface) and see if I can learn something. Not sure if I'm ready to squeez the caps in the vise but maybe that's one funtion of the 'alignment tool'?

Thread: Evinrude Rod Cap alignment
Jan 9th, 2007

“…The caps are always wider than the main part of the rod.We spring them inward with soft (paperboard lined) jaws in a bench vise---very carefully until they fit with just an index finger holding the cap in place. Then assembly in the engine is easier and a sure bet!
I'm always inclined to give our assembly tool away, but, now and then we get a request for it's use by a customer.”

If you think that is your problem then you could buy a simple wood clamp at HF and use it to install the cap while squeezing the rod cap in for that perfect fit. One of those wood clamps is only a few dollars but can apply a lot of force by screwing it closed. A simple "C" clamp could do the same too... Just a thought... Let us know how everything works out, and post some pictures as well. We all like to see what others are dealing with...

 

[dueydag]

Re: Connecting rod cap install

Just to inform you the needle bearing cage always rotate as the crankshaft turns.