Output coupling

[azazzera]

I'm installing the output coupling back onto the tail shaft of the reversing gear. I'm using the tool from mmi to press it back on. My question is how far should it go on. I pressed it until I felt what I thought was increased resistance indicating that it's seated. But I still can see a good portion of the tapered part of the coupling. How close to the flange should the coupling sit. (In inches or mm if you prefer). I think it said in the manual that the coupling should bottom out against the "special"washer. Just don't want to hurt anything at this stage of the game.

[hanleyclifford]

I have never used a press-on tool in this application. I just drive with a large impact socket and ball peen until I feel the "bottoming". In any case the nut will draw the assembly in tight. The important thing is to start out deburred, cleaned, and lightly oiled. The actual assembly should be a non-event.

[Cool Beans]

This isn't like a bolt that you can keep torquing on as it stretches Keep turning until it bottoms out. . .you'll know when it does because the nut will stop turning. . .that's it, lol. Try and snug it up until you can fold a lock washer tab over one of the flats of the nut.

For reference, the back of the flange is about a 1/4" from the seal face? Just me eyeballing it

[azazzera]

thanks for the direction. Ill take another look in between other life matters. thanks again. On another unrelated topic. I have been reading the Bowen Island Paint Job thread. good stuff. should be required reading for Atomic 4 101 class. thanks again

[azazzera]

Some more advise if I could ask. I have pressed the coupling as far as I dare.
Perhaps an1/8 or a bit more away from the "special " washer and tail flange. Is that ok. Dose it need to or normally always rest on that washer. My concern is damaging the seal if I try and push it in any more. I should check again but I believe that the coupling is matting with the bearing. Don't recall if it is flush with the inside plane or close to. Any further details about how these parts souls mate would be helpful. Thanks again. When I get a chance I'll send pictures.

[hanleyclifford]

Check out page 53 of this link. http://www.cncphotoalbum.com/atomic4/partslist.pdf Note that the spacer (#2) together with the rear plate (#5) defines the fore and aft position of the tail shaft.

[Cool Beans]

A picture of what you are seeing would be helpful. If the coupler isn't tight against the washer and the nut snugged up. . .the coupler could shift forward which would take pressure off the nut and lock washer tab. . .which could allow the nut to eventually back off and possibly lose the coupler in reverse

That's a stretch, but it could happen.

[azazzera]

here are a few pictures to view. the first picture i hope needs no explanation. Its afar I have pressed the coupling to were i think or feel that it can go no further. the second is of the inside trying to show the space left between the end of the coupling and the machined flange of the tail shaft. I have pushed the "special" washer aft against the bearing to reveal the space. dose it matter that the coupling is not seated against the tail shaft flange. I understand cool beans concerns but think that as he suggests the likelihood of the coupling seating itself further aft is unlikely based on the force it took to press it to that point it is now. I can't get a good look at how far the coupling is onto the bearing. that would be an obvious concern that the shaft of the coupling is supported by the full width of the bearing. the coupling is seated deep enough to reveal a thread or two after the nut has been applied. Thanks again for the replies.

[hanleyclifford]

The first picture seems to show the correct relationship of the parts when assembled but the second picture is a head scratcher. No gap can be tolerated between the coupling and the fixed flange on the shaft. Could you please label the components in the second picture also indicating which direction is aft?

[azazzera]

In the second picture aft is to the right.

[hanleyclifford]

I have to admit that I'm not sure what I'm seeing in that second picture. I think I identify the shaft flange on the left and moving right I see the gap, but the next piece does not appear to be round...

[hanleyclifford]

I found some old stuff in the shop so maybe we can see it a little clearer. The first picture shows the components slightly "exploded". The second picture shows the assembly together sans bearing. Note that there can be no space allowed such that the washer might be "free". We can see the possibility that if the key were too deep in the shaft such that it started to "rise" out of the key way, it could jam the coupling and keep it from seating "home".

[azazzera]

So seeing your pictures immediately had me recognize that the coupling I installed looked different than the one in your pictures. I found my old one and it looks like the one in your pictures. The coupling I got from mmi has more of a slope where the flange meets the bearing shaft part of the coupling. Boy is tough to describe things when you don't know the proper terms. Anyway. I think I have to remove the coupling I installed and compare it to the old and take some measurements. My thought now is that the shaft part of the coupling is simply different dimensions than the original. Or the whole reversing gear is not sitting on the crankshaft properly. I did have the reversing gear compleatly apart. I'm wondering if the fault is in the way I put it back together. This is when I start to get nutty with the whole process. I'll start with the simple things first. Looking at mmi catalog again to see if I could have purchased the wrong coupling. I have a direct drive. Then remove the coupling and take some measurements. Thanks again for all the help. I sure hope the discrepancy is not in the reversing unit.

[hanleyclifford]

You may have a reduction gear coupling. How many threaded holes in your coupling?

[azazzera]

It has three threaded holes. I took the coupling off last night and compared it to the old one. It has the same dimensions as the original. Except for the slope as it turns into the flange. I don't know if it was a 90 degree from the flange to the shaft if that would account for the complete distance but it is definatly pushing up against the seal. What would be the possible tragedy that could befall the engine if I ran it with that space.