sanity check for speedo mod required

[Tony Martyr]

I would be grateful for anyone with experience to sanity check the following

proposed modification.

Since I can't stop the Speedo drive in the tail end of my 6 speed box from

leaking oil I am going to abandon and seal it.

I will replace the entire Speedo with an electric type using a magnetic

pick-up like the Eclipse unit on page 139 of the DT catalogue.

I assume that this can work off a magnetic fixed to the prop-shaft or front wheel.

I want to remove the old Speedo drive shaft with the gearbox in situ. Can I

knock it out upwards and push out the top sealing core plug with the whole

box in situ? I seem to remember that the little shaft and drive wheel goes

in from the top and the plug goes in afterwards.

Putting the core plug back in will be tricky but should be possible with a

modified G clamp?

Once the shaft and seal are out I will turn up on a lathe an O ring sealed

plug with the same disk collar as the brass cable drive fixing had, that can

be held in place with the same circlip.

Does this all seem feasible?

 

 

[EFA]

Tony,

 

I noticed in assembling the Counts car that there is some sort of rubber/metal washer that holds the speedo drive in tight and seemingly oil no loger leaks. Have you tired this...?

 

On the other hand, I do not know how you will seal it. I still run the pinion gear in my box although its only ever run with a Stack.

 

Are you going to weld up the casing or something???

 

 

 

 

 

Fat Arn

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Edited by - fat arnie on 9 Oct 2001 19:29:19

[Tony Martyr]

Arnie,

The shaft comes through a metal and bonded rubber lip seal that is pressed into the ali casing bore and this seems to be the only support it has . I intend to replace this seal, when the shaft is out, with a plug that is retained by a circlip and sealed with an O ring.

I am going to take the car for a run with the speedo drive disconnected to see if the seal leaks as much when unconnected - which must be the normal state for your car.

Where do you take the speed pulse from for your Stack unit?

Tony M

[Nick VVC]

Tony,

 

Although I've still got the standard speedo installed, even though it gave up the ghost a while ago, I have a Stack ST50 fitted with the sensor mounted on the front offside wheel. This seem to work fine and is, as far as I can tell, far more accurarate than the standard Caterham speedo ever was.

 

Nick