Repairing gearwheels?

[minorman]

Hi All. It's good to see the VMR thriving, although I am not a full member. (maybe that should be 'because I'm not' so I am not dragging the group down }
I have a 1931 SV saloon and one of the teeth on the pinion is chipped resulting in a very noisy slow ride. I can't see any damage to the crown wheel. While the unit is out of the axle I will also take the opportunity to check the sun and planet wheels. Is it possible to have a gear repaired, eg the tooth built up with weld? If so, does anyone know who could perform such an operation?
If I have to replace, should they be done as a matching pair?
Dave

<edit is...I should have said I'm in Sussex>

[minorman]

Right, I went to a tame welder who does work for the museum I volunteer at and he sucked in a sharp intake of breath and said he would rather not try because if it breaks again the weld would destroy more than the original tooth had done.
So it looks like I am on the lookout for a9/44 Diff
Dave

[Sam Christie]

Dave, surely what you need for a 1931 SV saloon is an 8/43 crown wheel and pinion ?
If I understand correctly the 9/44 is only suited to the OHC engine and particularly an OHC car with a lighter body such as an M-type. In a SV saloon the 9/44 would give very laboured acceleration and poor performance on hills.
A new 9/44 could cost £300. My friend Garry Waiting in Kendal has a new 8/43 CW & P for which he would accept £50. Garry can be contacted at gmwaiting@hotmail.co.uk

[minorman]

Hi Sam
Thanks for that info. I will email Garry. I looked in the Morris Register information manual, and as you say, the 9/44 was in the 1929-31 OHC. It quotes 8/43 for the SVs and other combinations appear to have been used, ie 6/33 7/37 9/43 & 8/39, while for the 1932 coupe and Family Eight 8/47. I guess it depended who supplied them cheapest at the time
Mine has/had a 9/44 and 400x19" tyres. I bought a set of 3.50x19" at the Ardingly VCV Show as mine are 8 years old and hairline cracks on the walls. While I am waiting to source the diff I am replacing them.

The combination of oversize tyres and high ratio axle explains why I struggled up hills. Maybe I will end up with a rocket! My other reason for going down a tyre size is to reduce stress on the steering. It looks like I will reduce the overall gearing by 1.8% on the axle and 4% on the tyres - say 2.5mph at 50mph.
Dave

[Toby]

My sv saloon is labouring (despite engine rebuild) and has had an 8 brake conversion, I'm wondering if I now ought to check my ratios as well as timing etc!

[chris lambert]

Hi Toby,
Don't be hasty! Give your engine a chance to run in properly. The Semi-sports has now done 1500 odd miles and is a totally different engine to that which pulled me around Dorset last year. It is a revelation and did pull 56mph on the flat two up a few night ago (sat nav verified!). A change of oil after 500 miles to a semi-synthetic did make a difference and over time the performance just got better.
Chris

[Toby]

Engine man says not likely to vastly improve and we struggled to get home from rally having to rest after a couple of hills but I hope you're right! Must be something amiss somewhere to have the fuel evaporation, gets better as it warms, really on song after about 20 mins then after about 50 mins it starts tailing off as the engine really warms through thoroughly

[chris lambert]

Toby,
My saloon was still tightish after 1200 hundred or so miles following its engine rebuild. In the Semi-Sports I used modern oils (as mentioned in my earlier post) instead of the single grade used in the saloon and it seemed to free up much earlier. I am sure the oil we use plays a huge part in the way our engines perform. My modern Beemer does 30K miles between oil changes primarily because of the recent advances in oil technology.Having said that any number of things could be behind the sluggishness but changing the oil could be a useful first step - much cheaper than taking the engine apart again!!
Chris

[halbe]

Hello Toby,

This might be totally wrong, but are you absolutely sure that not one of the brakes is binding a little bit?
Give them a little bit more play just to make sure and then try again
If not I would take my engine man for a spin to let him feel for himself

good luck
Halbe

[Trevor Wilkinson]

Assuming that the engine is assembled correctly, ie valve timing and valve clearances, you need to make sure that the ign. timing is correct, and that the advance control is operating. Also make sure that the throttle opens fully and that the carb. is working properly and set up with mixture adjusted, or if have you got a "good" carb that you could try that.

Good luck from Ewan69 racing!

[Highlander]

Toby, Sorry to hear your minor is not preforming. If it runs well for an hour when warmed up and then peters out something must be more right than wrongYour valves, timing etc must be OK. Someone mentioned brakes. On this post I have mentioned my hydrolic brakes seize on sometimes and this slows me down to a stop. My brakeshoes are red hot and you cannot touch them, I just let off some fluid which does something and I am off again. It happened to me today on the Hogsback and I thought it was the long climb but it was not. When it happens again it is worth jumbing out and touching the shoes.Is your engine red hot when all this happens? Are you boiling? Is the petrol boiling in the float chamber? Have you tried driving in the dead of night? Over to someone else who must know more thyan me. All the best Highlander. PS I mean touch the drums NOT shoes.

[Simon]

Toby. Have you checked that there is enough free play in the linkage between the brake pedal and the master cylinder. If the piston in the master cylinder does not fully return then the brake fluid remains under pressure and the brakes partially on. [ This could be Alister's problem as when he lets some brake fluid out the brakes come off]. Might be a good idea to strip and clean the master cylinder and fit new seals.

[RLucke]

Advice on repairing gearwheels? DONT!!! Apart from the problem of reprofiling the tooth, the material would be hopelessly weakened by the heating of the weld.
I have successfully built up engagement dogs on the end of a gear, but still needed the equipment to be able to reprofile the shape.
As for Tobys lack of performance ( HI Toby) Apart from all of Trevors good advice,valve timing, tappet clearance ect, the biggest change I made to my CMS was when I put Duckhams oil in it instead of thick mono grade.
I also fitted a heatshield between the carb and the manifold to prevent vapourlocks in the fuel supply.
If you suspect the brakes are binding, there is an easier way than adjusting them. After a run, feel the drums to see if their hot. If your finger goes sizzle, then thats your problem!!
When I had a post war MM Minor,SV, I reckoned that it took 1000 miles before the engine ran freely after a rebuild. Cheers. Roger.

[Toby]

Thanks all! We seem to have strayed from gearwheels and I should have opened a thread! The drums were checked many times over the 500 miles to rally and back due to my concerns over lack of braking and new parts fitted, definitely no trouble with binding. The hot lumpy running is due to hot carb and I'm going to check tappets whilst doing the 500 mile retorque of head, also will check timing. I will try a multigrade for a while too but am concerned due to lack of filter with a detergent oil, I have inherited a whole oilfield in my Dads garage so it'll be good to use up some of the oil! Perhaps I should get some racing oil when it's all sorted out?