Differential swop

[Eric Smith]

Hi guys - the idiot is back

I have been asking for help off all of you for ages, and there has been a huge amount of advice and support offered, but sadly for you I Mr Dimwit am back again looking for information.

My Standard 8 is fitted with a 1147 Herald engine, a Standard 8 gearbox and a Standard 8 rear axle.

With all of your previous help in mind, I know I need a Triumph Herald GA prefixed 4.11:1 ratio differential or a Spitfire FC prefix 4.11:1 differential to help my car work properly, I know that both should fit in the Standards axle. I could even fit parts from the Standard 10 which is 4.55:1 but I guess that could be my default position.

My question is WHAT BITS DO I NEED TO CHANGE? I am guessing the crown gear and pinion, oil seals and gasket do I need to change anything else?

Please be gentle 

Eric

 

[johny]

Ha ha we all started off idiots...

Rebuilding a diff is not an easy job and most leave it to specialists. This is because when you move crownwheel and pinions their bearing preload, backlash and alignment has to be set which requires precise measurements and then shimming correctly or you end up with a noisy unit that could fail rapidly. 

[Pete Lewis]

if you get a full assembled diff it should ( the bevel gear carrier) fit in the std 8 axle 

obviously you need to split the back case and remove the output shafts so the half shafts have location in the diff gears, dont have to mess with crown wheels and mounting distances 

never done this but that how i would plan , 

Pete

[Eric Smith]

Hi to Pete L and Johny - thanks to both of you taking time to reply, and importantly thank you for the replies and the information you bathe have provided.

Eric

 

 

[johny]

Let us know how you get on as your project is a bit out of the ordinary👍

[Pete Lewis]

have no idea but need to make sure the  two diff gears have the same spline as the Std 8 half shafts 

if there is some difference you could  swap the diff gears over from the original without upsetting the crown and pinion mesh distances 

Pete

[Eric Smith]

Hi guys

I can only say - “well it’s like this” - according to the voices on the Standard Motor Club forum the swop is easy peasy, a matter of undoing bolts and doing them up again with the new differential in place, - however being a former member of the working fraternity who spent most of his life fixing things I am sceptical BUT I am trying to be optimistic whatever transpires will be reported to you all when the deed is done - or NOT

Eric

[johny]

What did that company say?

[Eric Smith]

Hi Johny

I was doing some research about differentials on my Standard 8 and the ones fitted to the Standard 10 and Pennant.

Apparently Lotus fitted Standard 10 rear axles to the early Lotus 7, what I could not find out was the differential ratio and which brakes they used - if it was the SMC factory fitted differential it was 4.55:1 (on my Standard 8 it was 4.88:1).

Stirling Moss had a racing Standard 8 with a lot of factory mods which I believe include a Standard 10 engine, gear box and rear axle, but again I cannot find a differential ratio he/they used. 

It would be interesting for me to find out more information about early Lotus 7’s and Stirling Moss’s Standard race car.

As to talking to people about restoring my differential well the words potentially expensive and awaiting replies from potential restorers come to mind.

The saga continues………

Eric