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Overdrive Or 5 speed?

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Thank you all, for your comments. On balance and after much research I am going with the rebuilt A type OD & transmission as a unit from Quantum Mechanics. I will have a local British car Mech. install it so it should go well. Again, Thanks to you all and Happy Triumph motoring to you.
 
P.S How would you describe a monster fire breathing TR6? What kind of HP are we talking about? My TR4 dynos at 115 HP with 135 Ft lbs tourgue. Only modification is 87 mm pistons and I went to SU carbs with Petronix ing.
 
lpool15 said:
P.S How would you describe a monster fire breathing TR6? What kind of HP are we talking about? My TR4 dynos at 115 HP with 135 Ft lbs tourgue. Only modification is 87 mm pistons and I went to SU carbs with Petronix ing.
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New-off-the-showroom-floor especially the later de-tuned TR6's were little better, if any, than the TR4's. In fact the power to weight ratio might have not been as good.

Remember that the 1970's were the years of the Noids, as in paranoids. And the government restrictions on vehicles became a smothering mess.

The potential difference becomes more obvious when rebuilding and at somewhat comparable build levels from the Paeco charts the four has about 75% to 80% of the power of the six. Which I feel is still impressive.
 
lpool15 said:
...I am going with the rebuilt A type OD & transmission as a unit from Quantum Mechanics...
Click to expand...

FYI - I just put one of John's Type A's in over Christmas. Very nice except it was very difficult shifting into 2nd. I mean almost impossible.

John said to give it time as it was probably just that the new synchro would need some miles/shifts to break in.

Somehow I managed to put 1,000 miles on it in January w/o even leaving town -- as John predicted it was shifting much better after 500 miles and is just great now.

I just pass this along in case you encounter something similar.

My only regret here is that I waited so long before doing this.
 
i have the same dilemma. i have an a-series overdrive that needs rebuilding, but as some of you know, i am aiming for 145hp, 148 ft-lbs torque. can the early gearbox and tranny take the power. NOTE:this is the early thin bell housing. I am very mechanically inclined and am not afraid of doing the rebuild myself or doing a supra 5-spd conversion. i like the originality that really makes it british but i don't want to do a tear down every 2 years. (mostly road driving).
 
The boxes are supposed to be good up to about 200hp.
At that point you want to be taking a close look at your diff and halfshafts too.
 
the toyota will take more than 200 but its' the triumph gearbox that i wouild like to use if its' strong enough. according to Kastner and Piggot, i'd be on the edge of reliability. anyone with 150hp with the early gearbox had any problems because of strength?
Rob
 
OK - here's my TR6 O/D 'war story'. About 10 years ago a guy sold me a g/box and A-type OD pulled from a scrap car for $750. Had to replace the side cover that the solenoid mounts to - it's vulnerable to breakage when it's off the car. Not too much of a problem since it was available from VB. Also had to buy the speedo angle drive, longer speedo cable (I think), the electrical harness, and switch. The disappointment was that the gearbox was done for - one of the gears up front was was mostly ground away (I think it was the gear on the layshaft that engages with the gear on the input shaft). The gearbox I was taking out was already noisy, and I wasn't going to attempt stripping it down, trying to switch the output shafts, etc. So I used the dead gearbox as the exchange one for a rebuilt one from Rimmers in UK. As I recall the shipping to the US was very low (free special even??) - sending the exchange back was $$ though. I went through and changed some parts in the overdrive- the accumulator o-rings seem to stick in my mind. 10 years and probably 30k later I have been happy with it. It does leak, I should have changed the tail shaft seal, and I think it is oozing at the joints between g/b and o/d. As far as being hard to get into second, the old one and new one have been the same way- only an issue for about the first 5 minutes in the cold. As far as all up $$ - I think all together it was around $2000- more than I had planned on, but I do think it adds a lot to the car. People are looking for it when they're TR6 shopping, for sure. Good luck with the new one.. - Pete
 
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