Clutch Dog rebuild

[lark2004]

Re: Clutch Dog rebuild

my spare motor that has the detent balls is a 1971 model. Maybe they never droped it in the Australian models....

 

[Paul Moir]

Re: Clutch Dog rebuild

I don't know precisely when they changed. It doesn't look like the '65 gearcase was worked on. I presumed they came in when they switched the bearing arrangement from the pinion tapered roller bearing to the revised pinion bearing with the separate thrust & two roller bearings.<br /><br />Anyway, I think it makes more sense for me to draw it. Hopefully this is a little more clear:<br />

<br /><br /> http://www.tinypic.com/m757rt.gif <br />I forgot to indicate that the prop shaft line is the *bottom* of the propshaft splines, and the inside clutch dog line is the *tip* of the clutch dog splines. IE, the neutral groove only goes *slightly* beneath the base of the splines.

 

[byacey]

Re: Clutch Dog rebuild

Thanks again for all the effort put into this. I found 2 balls that look like they should do it, .250 exactly, according to my micrometer. Should be able to find a spring amongst my collection. Are the slots in the dog ground or milled? I am kind of curious why they removed such a wide width of material for the ball to ride on when only 3/16 to 1/4" is required? So if I understand correctly, the neutral ball recess is only slightly deeper than the depth of the splines? Can the ball click be felt on the remote lever when shifting?

 

[Paul Moir]

Re: Clutch Dog rebuild

No problem at all. Might as well make it abundantly clear once and be done with it.<br />You understand correctly. Just a hair under the spline "valleys". It looks to me like they were milled. There are horizontal lines like tool marks. But if the grey colour of the metal is from heat treating, they must have machined them before the heat treat since those areas are greyed too.<br /><br />You can just feel the detent with the shift lever. But the one I tried has a detent spring from the spring collection, so it might not be as stiff as the stock spring. But the feeling of force from the quadrant bar which acts on the shift lever itself is far stronger. There's a certain amount of play associated with the bellcrank, since it's just a bolt.<br /><br />Mind you, the neutral detent makes the quadrant bar adjustment a snap. Literally. <br /><br />My only guess as to why they extended the groove so far is to make installation a little easier. When you slide the clutch dog onto the prop shaft you can be off a spline or two and it'll still work right. Sound likely?

 

[byacey]

Re: Clutch Dog rebuild

I suppose that might be the reason they would machine such a large surface. I am thinking of using an appropriate size end-mill to cut the neutral detent slot. If I clamp the dog on a 45 degree angle on the mill table that should do it I think. I wonder just how hard the splines are from the heat treatment; I might have to anneal the clutch first. Then again, maybe it might be easier to just find a worn one already factory milled and fix up the worn dogs; except that wouldn't be nearly as much fun, would it?

 

[byacey]

Re: Clutch Dog rebuild

Forget the end mill idea. These clutch dogs are too hard for any high speed steel cutters without annealing. I ended up grinding the 30 degree bevels with a dremel. All I need to do is find a round ball type grinding stone for the dremel to make the neutral detent. I assembled the clutch on the shaft with the gears in place, and the spring/balls certainly give positive engagement between the clutch and gears. Things are looking good, and I can see light at the end of the tunnel. I'm glad I took the time to do this; Thanks to everyone who contributed info here.

 

[byacey]

Re: Clutch Dog rebuild

One other question - is the quadrant detent on the gear shift linkage on the motor adjustable for position? I'll probably need to adjust this with the gearbox detent now. Ordinarily I would go have a look on the motor and figure it out, but I have it all tarped up outside for the winter.

 

[Chinewalker]

Re: Clutch Dog rebuild

Hi Bill, <br /> I've been following your project and it sounds like you're making good progress. If you get this down to a science and care to make it a little cottage industry, I have a box full of used clutch dogs that could use a tune-up. Maybe give you the whole lot in return for a couple-three rebuilt ones? If the process works over the long haul and they last a few seasons without a problem, you could make a few bucks selling them on eBay... A lot of those dogs are NLA from Bomby. <br />- Scott

 

[byacey]

Re: Clutch Dog rebuild

That's a nice sounding offer, I want to test mine out this summer and see how it holds up. I'm going to experiment with re-hardening the "ears" and see how that goes. If you don't mind, send me your private email and we can discuss this further.<br />Thanks

 

[Chinewalker]

Re: Clutch Dog rebuild

Hi Bill,<br /> It's csr112-n@prodigy.net. <br />- Scott