Convert ATF pump coupler worn, now what?

[brider]

This is a follow-up to my recent rotor-removal thread. I got the front cover off, measured a few things, but the real problem (it's a Cal 2 auto, pulled it off the road because the dreaded auto-slip began again suddenly) looks like the pump impeller (?) is worn and rounded and oversized to the "6 mm" hex shaft to the point that it needs to be replaced or have the shaft welded in place.

The shaft didn't look too bad, engagement length looked adequate and the edges didn't look too rounded:





To my surprise, it measured under 6mm, but so did every other 6mm hex wrench I had:





For future reference in case I want to have a 1/4" hex surface-ground down to a better fit, a 1/4" hex measured slightly over 6.2 mm:




host an image


As best I could measure, the cam hex measured slightly over 6 mm:





But here's the ugly part: The pump impeller looks really sloppy and worn, and the smallest measurement I could get by rotating the caliper on-axis with light pressure on the thumb wheel was about 6.40 mm, way too sloppy for the 5.90 mm shaft:

Oops, image loader is "down for maintenance", but suffice it to say the pump hex interface is worn beyond useability.

Opinions on how to proceed? What are the chances of finding a non-worn (or as badly-worn) replacement in someone's garage stash?

If I WERE to find one, the idea of a custom shaft ground down to different sizes for the cam-end and pump-end doesn't sound like such a hair-brained idea.

[fotoguzzi]

I might have one still in a timing cover hanging in my garage stash.. I’ll look for it tomorrow.. if it’s there you can have it for free.

[ray bear]

That is what I did as my convert was worn more in the pump than the cam so machined a hex with two different ends just so long as there is a little wiggle room for alignment/ expansion but why so much wear, when I acquired my  convert it was pumping 55 odd psi hot double the recommended spec which would have been placing a lot of stress on that hex  , Check your pump pressure , I think the book says 28psi . I had a master gauge on mine for a while and the pressure climbs high when cold so the first 5 minutes of the ride keep the revs down and be kind to the pump drive. Ray

[Antietam Classic Cycle]

If buying a used pump, be aware there are two different "socket" depths. On early pumps the socket was only 8 mm deep, on later pumps this was increased around 12 mm. 

[bigbikerrick]

This is very interesting to me. :popcorn:I ride my convert in very remote areas where there is no cell service, and its always on the back of my mind, as I am pretty sure I have sorted all the other little issues that may leave you stranded. It would be nice if we could get some sort of coupler machined to sort this slipping hex problem, once and for all.   Brider, have you thought about adding a pressure gauge to your Cal II auto?  A forum member that is very knowledgable on converts, recommends it ,and I have been thinking of adding a pressure gauge to my convert. I believe it only has to be plumbed in to the pressure line where it enters the bellhousing. I think its the upper hose. I just need to find a nice small  pressure gauge and a location to mount it.
Rick D,

[brider]

Here you can get the idea, the pump has been rounded and the fit is sloppy with the 5.9 mm hex shaft, I'm positive this is where the slipping is occurring:

[brider]

I might have one still in a timing cover hanging in my garage stash.. I’ll look for it tomorrow.. if it’s there you can have it for free.

Awfully nice of you, thanks.

[Antietam Classic Cycle]

Here you can get the idea, the pump has been rounded and the fit is sloppy with the 5.9 mm hex shaft, I'm positive this is where the slipping is occurring:

IIRC, Guzziology has a section about the coupler part of the pump being improperly heat treated, with that being the result.

[Shiny Hat]

This is very interesting to me. It would be nice if we could get some sort of coupler machined to sort this slipping hex problem, once and for all.   Brider, have you thought about adding a pressure gauge to your Cal II auto?  A forum member that is very knowledgable on converts, recommends it ,and I have been thinking of adding a pressure gauge to my convert. I believe it only has to be plumbed in to the pressure line where it enters the bellhousing. I think its the upper hose. I just need to find a nice small  pressure gauge and a location to mount it.
Rick D,

Can you adjust the pressure on this pump? Is the gauge to just monitor pressure, no more no less?
For accuracy you want the spec pressure to fall midway on the gauge scale (read 25 PSI, use 50 PSI gauge) One post said it was reading 55 PSI so maybe a gauge of 75 PSI to protect it from spikes. Use a glycerin dampened gauge.

[brider]

IIRC, Guzziology has a section about the coupler part of the pump being improperly heat treated, with that being the result.

I remember reading that, yes, but I don't recall what the fix was? Did the factory eventually begin supplying properly heat-treated parts? I would've guessed by '85, any remaining stock they had to build Cal 2 Autos would have the heat-treating problems solved.

I also don't recall a lot of discussion in these pages about non-heat-treated pumps....seems like the only solution would be to heat-treat a new replacement, and damage would've already been done to a non-heat treated part.

[bigbikerrick]

There is a pressure relief valve, i believe in the front cover by the pump. It has a spring and shims, where I bet the pressure can be adjusted, by changing the shimming. the pressure gauge would show a drop in pressure, if the couple starts slipping, before overheating the TC.  The gauge would also show if the pressure were high when the fluid is cold, etc, like mentioned above.
Rick D.

[brider]

I'm going to review the pressure-guage installation on these pages and in my e-mail/PM history. I've talked off-line with some of the Convert gurus in the past, and a guage sounds like a good idea "just because", but also a temp guage would come in handy, and I'm sure there are digital varieties that will display both.

[Shiny Hat]

There is a pressure relief valve, i believe in the front cover by the pump. It has a spring and shims, where I bet the pressure can be adjusted, by changing the shimming. the pressure gauge would show a drop in pressure, if the couple starts slipping, before overheating the TC.  The gauge would also show if the pressure were high when the fluid is cold, etc, like mentioned above.
Rick D.

Changing shims on the relief spring would definitely change the pressure (adding shims would increase pressure). Sounds like a pain to access though.

[bigbikerrick]

I never had any issues with the hex on my 84 Cal II auto. I took it apart for inspection, and everything fit nicely, so I just replaced the seal and O ring,and it worked for 46K miles until I sold the bike. That bike served duty as a tug for a good sized sidecar, a Texas Ranger, so that pump coupling worked hard. It must have been the newer ,improved version, although I never measured the coupler depth. My current convert is a 76 that I got with only 10K miles, and sat unridden for many years, so I think it may have the earlier version.
Rick.

[bigbikerrick]

Changing shims on the relief spring would definitely change the pressure (adding shims would increase pressure). Sounds like a pain to access though.

It may not be too bad to access, if I remember correctly, its on the top front part of the front cover. Removing the oil cooler, may give enough space to get to the relief valve plug.
Rick.

[fotoguzzi]

Awfully nice of you, thanks.

darn, I have a timing cover but the pump parts have already been removed.  So the OP still needs one.

[brider]

I never had any issues with the hex on my 84 Cal II auto.

I don't know if my problems are of my own making (backfiring history), but I am mad at the bike for making me deal with this pump thing so many times in it's limited mileage. Irrational, I know, but sometimes I am just so DONE with this thing.

OK, enough whining. Glad I have another bike to ride.

[ray bear]

gauge adapter I installed on my convert, you will need a longer banjo bolt.adjusting pressure is delicate and by turning the spring end to end altered my pressure 5 or so pounds as the circumference/diameter of the spring being massed produced  is different each end and allows the ball to sit deeper in one end  etc , it takes very little to alter pressure so if some one has had it to bits and flipped the spring theres a good chance pressure has moved, you may have to gently file the internal circumference of the spring to allow the ball to sit in that tiny fraction further    Ray

[MattP]

no 1 the only thing the oil pump, the main thing the oil pump on a convert is to cool the oil pump thruogh the cooler ,  cool the tourk conveter the convert allways slips never locks up. So you could edm a larger hex in the cam and pump rotter , how ever    that will get it running but i also think the cause is misalingment of pump and cam tricky indicating that in but that is why some go many beeeg miles and others not so. the pump router is orbiting.

[brider]

some go many beeeg miles and others not so.

This sounds like it makes sense. Manufacturing tolerances all gone the wrong way.

For anyone interested, here's a pic of the "old style" short-engagement pump Charlie mentioned. I actually had this cover in my pile, hex looks much better than my "later" style:





My "later" style:

[Shiny Hat]

First off I’m not at all familiar with the hex drive on this pump other than what I see in the pics.
Here’s a big but and based entirely on looking at the pics in this thread. Can you cut a 6mm 6 point socket to length and interference grind the OD to press into the pump section to increase the hex contact area or is that open area for another component?

[bigbikerrick]

The "old style" one pictured has a circlip holding the seal in? I dont recall  any circlip on my 76, when I was in there, to replace the seal ,and O ring.
Rick.

[brider]

I dug up some old e-mails I exchanged with Rodekyl on this subject, he actually welded a hex shaft to a pump coupler (I've been calling it an impeller) for a road-side repair and it lasted him for a few cross-country trips, in fact it never failed, even with any mis-alignment to the cam. Tempting to consider.

He also mentioned EDM-ing a larger hex (as someone in this discussion also mentioned) into the coupler and then grinding a custom hex shaft to fit, I think as of today that will be my #1 plan until/unless I find an almost pristine replacement pump. I am not at all familiar with the EDM process, so I need to do some internet education. And then find someone local who may do it.

[Alfetta]

i have not opened up my project convert yet...(so i may be talking out my arse)  but i am assuming that the pump is driven by then hex shaft from the end of the cam ?
It seems weird to me that the pump has the hex so deep and short in the input shaft. also from the photos provided here, heat treating on the pump end of things is looking suspect.. (new design)

I think that turning a length steel equal the the c' bore above the pump hex. and then having a hex broached through it and then hardening it. pressing it into the pump c'bore using the hex shaft as an alignment guide.  once pressed into place, a couple of tig beads at the end to secure it would rectify this issue.

[bmc5733946]

Keep in mind this is a situation without perfect alignment. Reducing flexibility of the alignment in the moving parts may not be helpful. I think Rodekyl used an electric pump on his trike project to overcome this issue. His project was documented here, maybe a search would turn it up.

Brian

[brider]

I think that turning a length steel equal the the c' bore above the pump hex. and then having a hex broached through it and then hardening it. pressing it into the pump c'bore ....

I think this idea has merit, but would reduce the shaft length to a very short shaft. Not sure if that's good or bad. And has been mentioned, welding eliminates any mis-alignment forgiveness; maybe Rodekyl had almost perfect alignment from the factory on his roadside repair. Can't count on that, though (although I won't eliminate that solution).

[MattP]

i think the pump is called a tyycoid gear pump , any way i beleive it is made of powderd metal you absolutly need to verify alingment  do what it takes to get in alingment burn larger hex  1/4 in should clean it up       and install new alingment dowls so the next time the case is removed it will cime back in alingment.    tool maker i knew had a bmw brand motorcycle r90s input shaft wore splines on input shaft wore off 8000  miles replaced it same thing then welded up ground larger type spline made same for clutch 2 times . i told him the alingment douls arre off put engine and trans on mill table dial it in  turn up oversize alingment douls , but being then bullhead he was  no it was very painfull to see. oh he did finaly cure it he sold it.  i also said take the douls out and snug the bell houaing bolts and rev a few times it seak alingment, at lealt it would  not be forsed out  bu=y misalinged pins.

[wirespokes]

Just get a larger inch size allen wrench and grind it to size on both ends. With a precision grinder it would be easy, but could even be done carefully with a dremel.

If you're still concerned about the fit in the rotor (gaps) even though fitting snugly, use a bit of loctite bearing epoxy.

[Antietam Classic Cycle]

Just get a larger inch size allen wrench and grind it to size on both ends. With a precision grinder it would be easy, but could even be done carefully with a dremel.

If you're still concerned about the fit in the rotor (gaps) even though fitting snugly, use a bit of loctite bearing epoxy.

If you read the previous posts you'll see that's been discussed. But, that's not going to be enough for brider's rounded out coupler. I don't think using any sort of epoxy is a good idea as the drive piece needs to be able to move slightly to allow for any misalignment between the cam and pump. 

[bigbikerrick]

Can a new coupler be machined by someone with   tool and dye  knowledge and the proper equipment?  I hate the thought of our beloved Converts being "dead in the water"  because of a failed couple that is NLA.
Rick.