Spare triumph ??spitfire?? Diff

[Martin mon]

Hi everyone, maybe wrong part of the forum and apologies in advance but thought may be helpful to someone, I have some triumph spares which I am trying to sort through to keep for my vitesse MK 2 project going but also look to offer up at fair prices to club members for their herald/spitfire projects before getting shut on eBay or alike. I have plenty to go through to help out but though to start with a diff stamped FR which research tells me is a 1500 spitfire. I believe this is not compatible with rotoflex so may be helpful to other TSSC members?? As per photos. 

[johny]

Hi Martin, I think this diff could be used on a rotoflex and is a slightly longer ratio than standard Vitesse so could be a welcome upgrade...

[KevinR]

Martin,

The Spitfire 1500 diff (3.63 ratio) is an excellent diff to fit to a 2L car.  

Although it only has a 4 stud spring fixing, the casing can be drilled and tapped to add the extra 2 studs that you should really fit if you are using a Rotoflex spring.

 

[Pete Lewis]

yes  agree with Jonny    that should be a 3.63:1  ratio  a good one to have 

 you would need to swap the rear case of add two 3/8 x24unf holes to turn it into a six stud spring fixing 

easy to drill , i did one on my vit6  with a battery drill using the spring top plate as a jig .as i had a spit diff and tried a swing spring    ((hopeless)

Pete

 

 

[Martin mon]

Thank you Johnny, Kevin and Pete really appreciate the help. Where is best place to help members out with listing the obvious stuff like the SU twin carbs and manifold which is definitely not vitesse friendly. Got to keep our cars going 👍

[Pete Lewis]

as a member you can load your own classified advert for sale  on the main website  for free  if you log in 

The Triumph Sports Six Club - Classifieds (tssc.org.uk)

Pete

[Wagger]

In case it has been changed in any way, it is very easy to check the ratio whilst 'On he floor' or bench. Just rotate the input shaft by hand and count the number of turns required to rotate the output flanges one full turn. Mark with chalk or tape to make it easier. Just over three and a half turns will be a 3.63:1 ratio. Just over three and three quarters (almost 4) is 3.89:1.

Also check for backlash

Worth doing to be sure. Apparently, the 3.63:1 is most sought after for strength.

[Pete Lewis]

you will be most unlikely to check any crownwheel/pinion backlash   what you may find is the backlash of the diff sun and planet gears and that doesnt really have any effect .

you can only check crownwheel backlash with a dial indicator on the teeth and that has to be careful not to measure the ramp of the tooth profile 

Pete

[Wagger]

I stand corrected Pete. However, a really worn diff will exhibit lost motion if you rotate the input shaft to and fro and observe how much movement there is before the output shafts move. My 1600/6 became so bad that it 'Clonked' every time I replaced my foot on the accelerator after lifting off. It began groaning too.

If the history of the diff is unknown, then it may be better to have it all checked by an expert before fitting it.

[johny]

In my experience diffs are one of the stronger components in our cars and last pretty well although of course the seals do fail.

As long as they havent been run dry second hand units are quite often good because the donor car rusted away long before enough mileage had been done to wear out its diff😁

[Pete Lewis]

yes they are reasonably bullet proof in normal use 

the coupling rotation you can find is not crownwheel backlash  its worn planets , yes can get a clonk but its not a failure 

there is no spec for free play/backlash of these gears unlike the 0.007" on the crown wheel which is very small and you need very light fingers to detect it by turning the coupling 

so a 1/8 of a turn is not CW and pinion ...its not possible 

what does wear surprisingly as they dont turn  that much seems to be the bronzed thrust washers not overly available but easy to change without upsetting any mounting distance setting of the CW &P   Canley list the outer flat one but the cup ones are N/A

Pete

[Peter Truman]

Pete here's a pic of my Vitesse's brass inner spherical Planet Gear Thrust Washer after a diff case strip & clean up.

There was no apparent diff noise and the Rotaflex's hid any slack, it looks as if it failed very early in the cars life, I replaced it with similar thickness domed washer from a Diff Rebuilder where it came from an Aussie Holden, I hope it hasn't subsequently sheared like the original.

Did I find the other half of the original thrust washer No not even bits of it?

Edited April 15, 2023 by Peter Truman

[Pete Lewis]

Peter  its the keyring that saved the day !!!!

maybe the last diff  built  on a friday   

Pete

[johny]

I was going to say it might have broken in initial build and the other bit fallen out even before it was first run...

[Peter Truman]

19 minutes ago, Pete Lewis said:

Peter  its the keyring that saved the day !!!!

 

It's my spare set of Vitesse keys complete with an aftermarket brass ignition key with the Triumph (Standard) shield as the main part. I keep the broken on that set so their easily found out of the 3 Triumph model sets of keys& spares I keep on my bookcase.

I agree I think it was broken on first run in 68 there are radial scores on one side and no rubbing/wear marks on either surface, as said previously I think the Rotaflex drive feeling any effects.