Timing Pinion

[Joker_Bones]

IMG_20230727_120347.jpg

'55 G80 engine...
With the timing pinion and camshaft fitted, the camshaft teeth run right on the inside of the pinion which is much wider.
It looks odd to me, is this normal?

[56G80S]

Hi Jack, I think, sometime in the dim past, I had this circumstance and it worked.

Just a thought, when I most recently rebuilt the engine , this year, I checked the end float on the camwheels using plastigauge. I was at 15 thou! From memory, it should be close to nil although I left it at 2 thou. If this was your case and you shimmed between the back of the camwheel and the crankcase it would shift the camwheel into a better mating position? And make the engine quieter.

Of course, when you do up the timing side axle nut, the small pinion may shift a bit?

Johnny B

[SPRIDDLER]

Maybe they would engage more fully when the the shock absorber assembly is fitted as it would pull the whole c/shaft assembly a bit more towards the drive side?
The pinion is always wider than the cam gears.

Cam drive gears.JPG

[Joker_Bones]

Good points...
I have adjusted the camshaft end float to effectively nil. I haven't moved the bushes in the crankcase, I just flatted the mating surfaces and made a gasket to the thickness for near as possible nil end float.
Although the nut is not on and tightened I have put a socket on the pinion and tapped it on tight.
The crankshaft is pushed over to the drive side in the photo.
I've done this a couple of times before, I just don't remember it looking that offset.
I've looked back through my photos but only have a head on shot, you can see the pinion is proud of the cams but not by how much.

[SPRIDDLER]

I've looked back through my photos but only have a head on shot, you can see the pinion is proud of the cams but not by how much.

Whilst I was at Thrifty Peter's shed just now photographing and measuring other engine stuff I took a pic. The pinion is 0.75" wide. Yours looks as though it could be a bit wider and also stands a bit further away from the face of the t/s bush.....

[g80csp11]

also lower pinion not sitting filly home , perhaps a pattern part ( distance between crankcase and pinion)
its not sitting on shaft wrong way around is it ?

[Joker_Bones]

Yes... If it had fitted like that I would not have given it a second thought.
The pinion is 5/8" wide and it definitely sits further from T/S bush. It's as if the taper should be cut deeper into the pinion so it sits further onto the shaft, I have another pinion which is identical and sits in the same place.

[clive]

The pinion looks to be too far away from the bush as its usually a struggle to get the puller between it and the case. You say the shaft is pulled fully over towards the drive side and that a second pinion fits the same. Leaves me wondering if you have a new woodruff key which is not quite right or the angle of an old one is somehow stopping it going fully home. If old woodruff key I would be inclined to try doing up the nut and see if there is any movement. If new woodruff key check the dimensions. Perhaps with either make sure nothing has got under the seating and it is sitting flat.

[Joker_Bones]

It is the existing woodruff key, I had convinced myself the key was not interfering as you could just feel the rotation of the pinion taking up the side clearance of the key to the slot when fully on. But the way to prove it is to take it out and fit the pinion without it.
Lol, it's stuck, I can't get it out.
What's the trick for getting the key out?

[clive]

Not easy without damaging it. How about measuring how much it sticks above the shaft at the front and back and comparing that with the slot in the pinion. If it has been pushed backwards it will not sit properly but wil be down at the front up at the back. If you have te puller I would be inclined to bolt it down and see if it settles. Remember it's a left hand thread.