CW & P ratios

[Nick Mayne]

Potton in Bedfordshire .... hoping to get the van more used to come to the Centenary but probably bring it on a trailer (shame on you!) as I have to guarantee being there contributing to the Cambridge club presentations. We have a room upstairs and the group I am in are presenting A7s abroad.

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PS I did not intend to make the van into a hot-rod; it is not stable enough. Any ideas for anti-roll bars ?!

[Bob Culver]

Eons ago when my RP was everyday transport i pondered an anti roll bar but apart from acquiring an A35 one never proceeded. Anything that holds the car upright reduces the bump steer roll oversteer effect. I found hyd sas at the rear did this and improved handling enormously, despite theory. Any roll bar should theoretically be at the front where roll resistance is very low due, shackle arrangement, sa arrangement, flexible chassis. Hard to counter all these and would be very visible, and heavy. And the kpins would not like..

[Nick Mayne]

Well I have bitten the bullet and bought a new CW & P with a 5.67 ratio ie. 6/34 teeth to a modern tooth design. Not received it yet but I understand the diameter at the  pinion end is nominally 1" whereas my original one was 1.125". I am told I should use a ball bearing but that goes against the grain as the bearing takes side load and the original roller gives line contact but a ball is point contact. I could have a sleeve made but it would only be 1/16" wall thickness so a bit dodgy to press on. I suppose there is a suitable ball bearing but is there a roller bearing?  There must be someone on the forum who has dealt with this. The old roller bearing has a spacer integral to the inner race but no usual ID number. I attach relevant pictures.            

[andrew34ruby]

Thank you Parazine, you sound as if you are an expert. When I rebuilt (re constructed!!) the van I wanted it to be more useable so went for a bit more more power but things went a bit over the top. I ended up with a new John Barlow crank and CNC con-rods with appropriate pistons, sporty cam and followers with increased flow oil pump and oil filter from Pigsty, and an HC head from John Sutton (whom some may have known). Also a speedy exhaust manifold from Pigsty and inlet manifold from John Barlow. A bit of gas flowing from me and oversize inlet valves. Of course rebore and balance check (but it already had good balance) and an SU carb. New auto distributor and 12V system. All good fun but it did not seem to make much difference at all. Pigsty then checked it over and pointed out that I needed a non standard carb needle as everything else was changed. They modified one with emery on a lathe and now the engine starts at a touch and revs freely fine but does not seem to have much power on the road!! Yes it is very noisy and a good job I am rather deaf.
So I will look for a half decent 8/45 CW & P.

Nick, all your mods to the engine should mean more power at high revs. If you don't use high revs there will be little extra power.

[Parazine]

In my past experience, the ball bearings last for 40 - 50,000 miles. These days I do a max of 2000 miles per year so that's 20 - 25 years or more.

That'll see me (and probably the next owner) out.

I've never seen a spacer like that before, integral with the bearing. Usually, it's a separate piece. Has someone built something special here??

[Tony Press]

I have never seen a roller bearing with an extended inner ring ??? 

I would think it unlikely that Austins would have had this made. The material does not look like bearing steel. 

Not sure but something doesn't seen correct.

Getting back to the question-  as suggested the ball bearing would probably do the job now although the roller is a better solution (as Austins found out).

You will need a new spacer as well.

[Nick Mayne]

Well it was my mistake. The apparently extended inner race was actually the spacer which had worn into the bearing roller cage and the radius next toi the shaft on the inside of the inner race so that it was surprisingly well fixed and the joint inside looked like an oil groove. It did not come apart by knocking it laterally. I put it freely through my vice jaws and used a punch inside on the edge of the apparent oil groove and it fell apart. So apologies if you spent unnecessary time head scratching! Well I did as well.
The new pinion shaft unfortunately has a 1" diameter for the bearing instead of the original 1.125". It looks as if I will have to use the 1"/2.5" ball bearing as there does not seem to be a roller bearing available in that size. I am waiting for the shaft to arrive to see if I do need to have a new spacer made but you are probably right Tony.

[Bob Culver]

The ball bearings were not long lived in hilly everyday use but the rating of modern bearings is much increased since the 1930s (hence tiny bearings in powerful moderns). An advantage of the roller is the pinion can be repeatedly withdrawn to check assy mesh but presumably the new cwp will com with a gauge so no trial and error. Ball race much less expensive.Mind you not sold a C3 toleracne bearing. Careful thought needs be given the spacer length to ensure everything appropraitely gripped when assembled.
Dont throw out the old cwp. Anything with teeth intact might be useable!

[Parazine]

Ah! The old worn spacer problem.

This is usually the root cause of the nut apparently coming loose when the tab washer is undisturbed.

Beware of second hand spacers because i) There are two sizes, one for the ball race and one for the roller and ii) most of them are also worn. The spacers should be an exact imperial size (I can't remember what it is) so it's important to measure the length with a micrometer. Of course, if you're setting up a new CWP it doesn't matter so much if the spacer is 10 thou short as you can add 10 thou to the shims on the torque tube but it can get tricky if the spacer is very worn.

[Stuart Giles]

A 1/16" wall thickness steel sleeve Loctited (or shrunk) onto the pinion will allow you to use the late style roller bearing. The bearing in this position on the pinion is only taking radial load, so a roller bearing is always going to be far superior to a ball race for this job.