Overdrive pump cam

[sjb2oak]

Should the overdrive cam move on the gearbox main-shaft?
It doesn't rotate, because of the woodruff key, but it can move up and down the main shaft by about a millimeter.
I've got the circlip in place to stop it sliding off completely, but the cam still kind of wibbles around a bit!

[Carledo]

I've never known one to move, but that much movement is unlikely to be critical. On the other hand, a shim washer might be an idea, if it does move in service, it might wear away the rather fragile woodruff key.

Steve

[sjb2oak]

also i'm i missing a trick with getting this countershaft/layshaft into position??

[Henk]

I'm not sure if we're talking about the same thing:
I use a suitable length of PVC pipe which fits inside the laygear. Slide it to place the needle bearings. Then fit in the gearbox and push the PVC out with the layshaft. The layshaft replaces the PVC while the needle bearings have no opportunity to move out of place.

[Carledo]

I have an old worn layshaft which I cut a chunk off so it fits inside the cluster and use the bit I cut off to hold the front thrust washer in place whilst pushing the proper layshaft through from the rear.

Steve

[Jon Tilson]

The longitudinal movement on an o-d cam is disconcerting but of no consequence...its not going anywhere...

Dummy layshaft is what you need. Grease the thrust washer to stick them in the box and be very careful putting the shaft in so as not to displace them. First time you do it they will fall out - you get better with practice.

Jonners

[MIG Wielder]

In my experience those cams are quite a tight fit. If nothing else I'd have a look at the Woodruff key and maybe replace it anyway in case it has worn.
Tony.

[Jon Tilson]

Tony I'm sure he has had to fit a new one....
They have to come off to get the gears off and Ive never known one yet be re-useable....

Jonners

[sjb2oak]

Yes, new woodruff key.
The laygears with dummy shaft was in the bottom of the box ready to accept the new shaft.
I just couldn't lift it high enough to be able to get the new shaft in.
I think my problem was that he input shaft and main shaft weren't spinning independently of each other, so the gears weren't meshing properly.
Just got to figure out why everything too tight now?

Steve

[Jon Tilson]

I tend to tip the box over to let the layshaft drop into mesh with the mainshaft gears. Gravity does the job nicely.
...then you can push the lay shaft pin through carefully.
I suspect the brass synchro rings are sticking to the cones on some gears so they bind.. Try pushing them off with a flat screwdriver so all the gears rotate in neutral.

Jonners

[Carledo]

I make a sling for the laygear cluster from a chunk of the ubiquitous "blue string" This makes lifting it a one handed job and you can still see what you are doing.

Steve