wiring j type overdrive switches + overdrive 2nd

[dazzer]

On a J type I assume that to operate overdrive on second gear I would need to fit a switch in place of the blanking bolt over the 2nd gear selector?

Once I've done this does anyone have a diagram or could explain how to wire the switches please.

I need overdrive on second for quick changes in short tests. I'm also presuming that overdrive 2nd will be close to 3rd anyway.

Many thanks for any advice.

[AlanChatterton]

Yes, take out the large 1" blanking bolt and replace with a switch (isolator/reverse switch...... all the same)

Wire it in parallel with the 3/4th isolator......... ie a wire of each side of the 3rd/4th one to each side of the 2nd one.

However, be very careful.............. J types not that strong (unless you have had a special one built) and using o/d in 2nd it won't last long!

[thescrapman]

Overdive 2nd is half way between 2nd and 3rd, bridging the chasm between gears nicely.

And as indicated, do not expect the OD to last long.

Cheers

Colin

[dazzer]

Thanks guys

For the wiring detail and the warnings.

If it self destructs I'll replace it with something stronger.

Interestingly the A type on my TR4 has been wired to only operate on 3rd and 4th (normally on 2,3rd and 4th) due to the risk of damaging the OD with the uprated engine. So perhaps its a weakness in A and J types?

I'll post if it implodes.

Cheers

Darren

[Charles H]

I have a J type wired to work on second on the 2000 Mk1 rally car. I only use 2nd OD on tests that require more than second gear can manage, other than that it is a cruising gear. Not broken it yet, but it only produces 87bhp! :) I am led to believe that the J type is stronger than the A type! ;)

[Ridgetone Triumph]

My A Type OD is available on all gears Ist to 4th and reverse if you knock the switch in by mistake, only done this twice (makes  reversing hard :-/) until I realise what has happened.
I was using 2nd OD all the time when racing, just needed that split between 2nd and 3rd, not so much now, as I have more BHP :).