Silly question re speedo drive but I have to ask

[Colin Lindsay]

39 minutes ago, Pete Lewis said:

seem to recall the washer is of 7/16" dia     does that make a fit or rattling good fit  ??? we need to know when advising to fit or not to fit that is the .........

Pete

I used a 7/16 washer and yes it's a rattler. Pic for demo purposes only... compared with the copper one. It needs to hold the drive out to achieve distance, so as long as it does that it doesn't need to be any thicker or broader. It sat, fine and dandy, until the drive was tilted for fitting then I can only assume that when off-centre it pressed on the speedo drive sufficiently to jam the spindle. At least I'm hoping that's what caused it, as it's something I can avoid next time.

  

 

 

[Adrian Cooper]

Colin,

I had repeated failures of the angle drive on my Spitfire. I eventually worked out that the drive cable was too close to the exhaust because each time the angle drive broke it was after pausing during a long run; the drive would heat up on the hot exhaust pipe and seize up and destroy the angle drive, but be perfectly free when I came to take everything apart for repair. I got very good at repairing the angle drives. I did a post about the repair method on here several years ago but Pete outlines the method in his post above. Check the route of your drive cable?

Adrian

[Joanna K]

2 minutes ago, Adrian Cooper said:

Colin,

I had repeated failures of the angle drive on my Spitfire. I eventually worked out that the drive cable was too close to the exhaust because each time the angle drive broke it was after pausing during a long run; the drive would heat up on the hot exhaust pipe and seize up and destroy the angle drive, but be perfectly free when I came to take everything apart for repair. I got very good at repairing the angle drives. I did a post about the repair method on here several years ago but Pete outlines the method in his post above. Check the route of your drive cable?

Adrian

Adrian, that's really interesting. My new cable broke last week and today I found out that it snapped by the angle drive. this happened after a good 40min run on the motorway

[Colin Lindsay]

13 hours ago, Adrian Cooper said:

Colin,

I had repeated failures of the angle drive on my Spitfire. I eventually worked out that the drive cable was too close to the exhaust because each time the angle drive broke it was after pausing during a long run; the drive would heat up on the hot exhaust pipe and seize up and destroy the angle drive, but be perfectly free when I came to take everything apart for repair. I got very good at repairing the angle drives. I did a post about the repair method on here several years ago but Pete outlines the method in his post above. Check the route of your drive cable?

Adrian

Cable is fine; it rotates freely by hand with no binding or grating but I'll bear that in mind when refitting a replacement (no point in reusing the original only to have it wear more quickly due to age) - however on checking photos I've spotted that the cable ran along the top of the chassis rail so was well away from the exhaust. The angle drive is also above the rear gearbox mounting plate so I'd have presumed it's shielded from rising heat, to some extent anyway. I can raise the cable slightly and try to further insulate the drive, it'll all help.

Try an Internet search on 'broken speedometer angle drive', there are hundreds of results.

[NonMember]

On 25/06/2022 at 09:31, Colin Lindsay said:

Assuming of course the overdrive isn't playing up. Last night I moved off in first, went for second gear, and the car again gave a lurch as if overdrive was coming on... in second?

As you seem to have got to the bottom of the angle drive problem, I thought I'd respond to this, while you've still got it apart. I had this problem on my GT6, despite the overdrive being so worn as to only work when cold, and traced it to mis-adjustment of the solenoid to operating lever. That was a D-type, though - I don't recall whether you've got a J-type, where that adjustment isn't readily available.

[NonMember]

22 hours ago, Colin Lindsay said:

I can raise the cable slightly and try to further insulate the drive, it'll all help

On at least some of mine I've added a P-clip to support the cable off the gearbox top. Mostly I did this for neater routing but it also ensures the angle drive isn't being "rattled" and vibrated (I had one car where the knurled nuts kept working loose so the cable fell off).

[Colin Lindsay]

There are speedo cable clips available but no-one has yet confirmed where they go; however from the look of them it's to clamp against the chassis rail. I might just dig out one or two for peace of mind.