accessory drive

[nyiftos]

hi guys,
question about the correct/wrong position of accessory drive gear roller bearings. is it possible to be installed wrong?
After replacing both roller bearings and oil seal, I took a closer look at the old bearings(which by the way were in very good shape for their age).
I noticed that on one side(end) they were straight/flat but on the other side(end) they had a slight rounded surface.
If I installed wrong side in/out is it some kind of trouble?
Should i have to removed and inspect/ reinstall them?
The reason I r/r them was for a noise in the area of the acc. drive.
By the way the noise is still there especially at the higher rpm's.
There is also a lot of play/backlash between the idler/accessory drive gears.
What do you suggest?

[hanleyclifford]

A Subtle Distinction

Good question. I hadn't thought about this for a while so I went down to the shop and looked at a unit I had not disassembled yet. The bearings had the "flat" ends facing outward so that then the rounded ends would be facing each other. I do not think this is a big deal and it is possible the bearings are made with one end rounded for easy assembly into their housings. It is also possible that the flat surface preferentially faces the direction of thrust. There is bound to be some longitudinal thrust vector anytime a shaft is being driven by a helical gear. In this case the acc drive is being driven counter clockwise, as you view from the front or pulley end toward the driven gear end. The direction of the gear teeth suggests thrust toward the pulley. See page 85 of the Parts List, Universal Atomic 4.

[nyiftos]

[QUOTE=hanleyclifford;79468]Good question. I hadn't thought about this for a while so I went down to the shop and looked at a unit I had not disassembled yet. The bearings had the "flat" ends facing outward so that then the rounded ends would be facing each other. I do not think this is a big deal and it is possible the bearings are made with one end rounded for easy assembly into their housings. It is also possible that the flat surface preferentially faces the direction of thrust. There is bound to be some longitudinal thrust vector anytime a shaft is being driven by a helical gear. In this case the acc drive is being driven counter clockwise, as you view from the front or pulley end toward the driven gear end. The direction of the gear teeth suggests thrust toward the pulley. See page 85 of the Parts List, Universal Atom

Thanks for the quick reply.
I agree on your thoughts, I also believe that there was not a need for the r/r of the bearings.The noise must be from the crude gear of the accessory drive and auxiliary drive gear.I believe that you will agree that to solve the problem of the excessive backlash and noise in that area, the only solution must be removal of the reverse gear unit and r/r gears,bearings/bushings etc.
I hope that with minimal use of eng. and careful operation, the gears etc will hold up for a very long time.
Again thanks.

[hanleyclifford]

Noise in the acc drive area is a persistent complaint and it seems there is little we can do about it. I know of no source for new gears and there is no way to adjust the backlash. The only thing you can do is check the idler gear spindle and bushing at your next haulout/teardown. New spindles and bushings are available from Moyer Marine, but I believe we are stuck with used gears. Also it never hurts to check the distributor shaft for wobble. FWIW, when I switched to 15-40W diesel grade motor oil things got a lot quieter. Edit: If you have a tachometer drive that you are not using, try removing it and just capping the hole; those things can whine a bit.

[marthur]

I know of no source for new gears

Now my curiosity is peaked. It would appear that Universal used a number of standard sized (or even "off the shelf") components when building these engines (like the seals, pistons, rings, valves and assemblies like the fuel pump, , water pumps and distributor, etc..). And those things are common enough that they are still available today. Thankfully or our sponsor makes it possible for the average sailor to find them (and the prices aren't bad either).

I wouldn't be surprised if those accessory drive gears came out of some 1940's / 50's / 60's /70's gear catalog. And that means that if you knew how to order gears, you might be able to buy them today.

So can anyone educate me about how to measure gears? What do you have to specify when to search for a replacement?

[marthur]

OK, just found this: How to specify and choose gears

Looks like I will be studying gears later today : )