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Rod caps will not align perfectly

P

PhilSch

Regular Contributor
I spent the better part of yesterday trying to align the rod caps on my 1988 Johnson 110 and was unable to get any of them to align perfectly on both sides. The best I can do is get only one side aligned where the seam is undetectable with fingernail. After several frustrating hours I called a boat repair shop; the owner said it was a piece of cake so I took it to him but he could not make it happen either. He said take the crank out and align the inside of the rod without the journal/bearings I but could not get any one of the four to become perfectly aligned off the crank either. Again, the best I could do is get one side aligned.

I numbered and applied directional arrows on all the rods and caps before disassembly so no chance of having mixed anything up.

I had a private conversation with a member of this forum who six years ago could not get one of his rods aligned, gave up and put it together anyway and it turned out ok; he has 450 trouble free hours of hard use on the motor. Anyone else have experiences, good or bad, with doing that?

I am thinking my rods are bad but there is no evidence of overheating. At this point I'm thinking I should get a used set of rods that I can return if they are no good and see how they align. Could I use my bearings with those rods or would I need new ones?
 
I hide in my humble workshop.----I use a little hammer and many years of experience.-----I put them together without the fancy factory tool !!!-----Nothing to it.
 
Heh-heh, me too. Years ago. But I don't know if that works on the newer stuff. The manual says trying to do it without the tool will ruin the rod. Costs too much to take the chance.
 
There is lots of information out there about that tool, many techs that have access to it don't use it. Some feel it often times creates as many or more problems as it solves.
 
You cannot use that tool on some rods. Make sure the rods are clean, threads chased and clean,clean clean. Assemble rods to crank,snug up the cap by hand and check alignment ..should look close . Torque to 10ft-lbs and check, the side that not quite give slight rap with ball peen tool. Then torque to spec.
 
faztbullet said:
You cannot use that tool on some rods. Make sure the rods are clean, threads chased and clean,clean clean. Assemble rods to crank,snug up the cap by hand and check alignment ..should look close . Torque to 10ft-lbs and check, the side that not quite give slight rap with ball peen tool. Then torque to spec.
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Pappy,

Thanks for that advice Pappy....part of my problem was I did not clean carefully enough where the rod and cap mate. I got everything squeaky clean and got rod number 2 perfect. Rod 1 is almost perfect but a very faint misalignment can be felt, I'm sure it is only a few ten thousandths off. Rod 3 and 4 are off more and in fact the rod caps are about .001 wider than the rods. I put the caps in my mill vise and cranked down on them repeatedly (trial and error baby steps) measuring with a mic each time. I managed to squeeze them down about a half a thou and alignment improved but not as good as I think they should be. Should I keep squeezing down on the rod caps to see if I can get them better? I tried the ball peen hammer action after tightening about 7-8 ft lb but no movement at all. Do they have to be perfect or are they tolerant of a very slight mismatch?
 
They have to be perfect.----After all they were " fractured " when they were made.----So they should fit together again.----I have never has to resort to putting them in a vice.----You are heading for disaster with that treatment I believe.
 
racerone said:
They have to be perfect.----After all they were " fractured " when they were made.----So they should fit together again.----I have never has to resort to putting them in a vice.----You are heading for disaster with that treatment I believe.
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Well the rods are junk then. The cap is .001 wider than the rod. It hangs over both sides of the rod. How can one make that fit without squeezing it?
 
racerone said:
Measured the bore to see if they are still true / round ?
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Finally got around to pulling the crank and checking the big ends for roundness. The two that mate the best were perfectly round. Number 3 was a few ten-thousandths off and 4 measured off about .0005. Those last two were the ones I squeezed in the vise which made them mate better but not not perfect.

My BIG question/concern is why does the inside of the rod not agree perfectly with the outside? Rods 1 and 2 (the two that mate well) differ from inside to outside. When there is a perfect alignment on the outside the inside is misaligned slightly! Given that, how can you ever be sure the inside is perfect when you can only check the outside?

I am going to buy some rods and start over. This is maddening.
 
That is a real interesting observation, which I have no answer for. But the parts are broken apart then bolted back together again and the I.D. and O.D. ground at the same time. So, they should match. At least that's what I've been taught. Hope this nightmare turns out ok for you.
 
fdrgator said:
That is a real interesting observation, which I have no answer for. But the parts are broken apart then bolted back together again and the I.D. and O.D. ground at the same time. So, they should match. At least that's what I've been taught. Hope this nightmare turns out ok for you.
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I just purchased foir refurbished rods for a very reasonable price and the seller guarantees that the Caps are aligned so I expect everything will work out fine
 
So the rods I'll be getting will not have been worn in with the crank journals. Would it be important to buy new bearings for the big end or can I run my original bearings which look good?
 
That could be a very controversial subject. If it were my motor. I'd probably reuse them. But if I were doing the job for somebody else, he'd be getting new ones. It's called CYA. Besides, it's his money not mine.
 
fdrgator said:
That could be a very controversial subject. If it were my motor. I'd probably reuse them. But if I were doing the job for somebody else, he'd be getting new ones. It's called CYA. Besides, it's his money not mine.
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I'm sure it happens but I never hear of anyone losing a 2 stroke motor because bearings failed. It's always piston problems due to overheating or lubrication issues. I'm leaning towards using the old ones as they and all the other bearings look great.
 
Crank journals are hardened and so are bearings...You see lil to no wear on a roller bearing engine. If it was mine..yea probably reuse em if good(no pits,dings,water marks discolored)...Customer always gets new. If it was a issue of matching you would have to replace crank every time you rebuild a engine, you just clean,mike, polish and slap NEW bearings in it.
 
faztbullet said:
Crank journals are hardened and so are bearings...You see lil to no wear on a roller bearing engine. If it was mine..yea probably reuse em if good(no pits,dings,water marks discolored)...Customer always gets new. If it was a issue of matching you would have to replace crank every time you rebuild a engine, you just clean,mike, polish and slap NEW bearings in it.
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Thanks Pappy for your valued inputs Pappy!
 
I got the four refurbished rods from Ebay yesterday and I am bummed. The seller is an active used marine parts reseller that has 25,000 ratings with a 99.9% positive feedback score. The rods shipped immediately, look like new (probably been bead blasted) and were packaged professionally. They have new rod bolts fully torqued. All eight flat surfaces on the outside of big end of the rods are perfectly smooth when doing the scratch test with a pencil or fingernail but the inside of the rods all have definite gaps easily discernible both visually and with a fingernail.

My first thought was maybe they just torqued them down without really getting them aligned and then machined the side surfaces smooth but they measure out the same width as my rods so I don't think that is the case.

I attached a pic of the outside and inside of one of the rods. All four rods are the same. The parting line can be faintly seen on the outside of the rod in this photo but it can not be felt. The inside parting lines of all four rods the parting line is very evident both visually and with the fingernail. I've been told by some very experience members here that the rods and caps need to be aligned perfectly and that makes sense of course so I am at a loss here.

Two of my original rods are as good inside as these four rods. One thought is to return two of them and run two of them along with my best two rods. Or I could send them all back and buy four new WSM rods. I have read that sometimes new ones won't line up either. Aaarghh!!!
 

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