crownwheel to pinion setup

[steve davidson]

Hi all,

Any input welcome

I'm trying to mate my crownwheel and pinion together and would appreicate a little adivce.  The CW and P are both new, brought as a set, but not sure if they are were "matched".  Anyway I've tried to get the markings as shown in the Woodrow manual but I'm not sure I fully understand what I'm doing.  I've attached link to a video that shows the contact patch.  I've also attached a photo with the contact patch marked in pink (the blue didn't come up well in the photo).   I think the contact patch is too close to the end of the tooth and needs to be moved back slightly  closer to the base of the pinion.  

My interpretation of the sketches in Woodrow and the comments around adjustments is that this contact patch shows that the pinion needs to moved nearer to the crownwheel by removing shims.  Is this correct or am I getting in 180 degrees wrong?

If it is correct then I'm in trouble as I've got no shims to remove.  If I add shims it seems to move the contact patch ever so slightly closer toward the axel line.  

   

One last question.  Am I correct in saying that if shims are added to move the P away from the CW then the backlash will increase and the adjusters need to be moved to push the CWtoward the P and vice versa if shims are removed.   

[Howard Wright]

Hi Steve

I normally put a bit more “blue” on several teeth of the pinion.  Bolt everything together including a spare gasket then turn the crown wheel using the pinion but putting a little bit of resistance By holding the half shaft tapers ( on early axles you can hold the crown wheel through the inspection plate). Take everything apart and inspect the crown wheel for the mesh pattern.

I couldn’t open your video but the photo seems to show that the teeth aren’t really meshing at all? 

You are correct in thinking that you need to move the adjusters every time you move the pinion.  Last time I did this it took me nearly a whole day. I was a bit fed up by the end ?. It still wasn’t perfect as the crown wheel and pinion were second hand and had some wear.

Good luck

Cheers

Howard

[Ruairidh Dunford]

Looks to be an early banjo axle - what type of crown wheel and pinion are you trying to fit into it?

I think you may have the incorrect pinion and/or tube type for the casing.

[Bob Culver]

You obviously have much to resolve but books all refer to the pattern on the cw, and instructions apply to these. Gets confusing when trying to adapt the instructions  to the pinion pattern although in a Seven much easier to observe. There has been extensive on this which Search should reveal. Some acheive at least the preliminary mesh with the casing split when all is clearly viewable.....
When tinkering care is necessary not to excessively load and ruin expensive bearings in thrust

[Ruairidh Dunford]

If your c/w & p are of the new design you must completely ignore traditional contact patterns and refer to the instructions from your supplier.

[steve davidson]

Hi Ruairidh,

You might be on to something there.  I have no history of the unit but when I stripped it I found a 8:42 ratio inside.  Markings on the differential case say 11/4/32 and then the numbers 8879 with an 8/42.  The torque tube looks like the one in Woodrow figure E4-3 but when I came to assemble it I found that the ball bearing adjacent to the pinion would not fit on the new shaft and I had to source a roller bearing as shown in figure E5-1.  Unlike figure E5-1 my torque tube does not have a separate bearing housing that sits between the tube and the diff.

So it looks like I’m trying to get pinion for a 1933 -39 unit in to 1932 torque tube, so that could be a problem I guess. 

Any thoughts on options? Our parts book (Queensland Australia) shows a 1928-29 9/44 option or what I purchased, a 1935-37 8/42.  Nothing for a 1932.  I’m assuming the 1928-29 option will not work as it suits a screw in torque tube.

I guess I could bolt it up and see what happens but that will always annoy me.  I see the A7 components site lists “5.25:1 (short pinion shaft) for post-1931 cars; with or without the 11/8" shoulder behind the pinion gear (as fitted from November 1934)”, I wonder if this is a viable alternative?

[Tony Press]

Steve,

Have you fitted a new pair of Angular Contact bearings (RHP LJT 1 special SKF ALS 8 special)  on the pinion shaft  ?

If so did you use the correct special 'narrow outer ring' pair of bearings ?

The video comes up with- 
"null
If the owner of this video has granted you access, please sign in."

Tony.

[Bob Culver]

I dont know the early diff variations, but the1933 on roller alternative pinion bearing requires some provision to prevent the outer ring moving endways in pre 1935 casings. Search should locate details.

[steve davidson]

Hi Tony,

I fitted a matched pair sourced throught our club, they were described as " matched angular contact".  I normally keep the boxes until I've got everyting sorted but in this case it looks like they made it in to the bin last week so I can't give you the exact code.

---

Hi Bob,

yes I was a bit worried about that outter race moving toward the crownwheel.  I installed with a loctite bearing retaining compound, but I'll have a search on the forum to see what others have done.

Thanks for the input

---

I think I found the issue with the video, hopefully it should open now

[Stuart Giles]

So it looks like I’m trying to get pinion for a 1933 -39 unit in to 1932 torque tube, so that could be a problem I guess. 

Not a problem fitting a 1 1/8" CW & P set into a 31/32 banjo axle with the later style  roller bearing. But because the roller bearing has a different depth to the ball race used in the early axle you need to use the spacer for a roller bearing pinion. When I've done this job on early axles, I've also drilled the banjo and fitted a peg (as per the later axle) to stop the roller race outer track moving out  towards the crownwheel.