Advice opinions please

[Green411]

Aaah...... light dawns, Andrew has a 4-speed....hadn't realised. I bought a part throttle kickdown module for my TF727 a while ago. It goes under the front of the valvebody and replaces another part. But I haven't summoned up the courage to take the valvebody off yet! I dropped the pan and changed the fluid earlier this year, not technically difficult although holding the spacer under the filter at the same time as getting the new filter in the right place so the bolts go in needs 2 and a half hands, which due to some design fault of mother nature I don't posess (yet...). I was going to do the kd module at the same time but chickened out, in case small unidentifiable bits boinged off into oblivion....
Thanks for the links.

[David C]

When you finally summon the courage to fit the kit you may want to consider fitting some updated Sonnax valves at the same time. The important one allows the torque converter to fill in park and avoids the clunk on take off.

I would advise against a shift improver kit. Martin Barnes talked me into one many moons ago and although it gives a more positive change it's a bit more boy racer and less Bentley. Personal preference but I prefer refined understatement until the pedal squashes the carpet.

[Green411]

Agree completely with David C about shift quality. I had a shift kit in the TH350 in my old V8 Ford Popular hot rod years ago. It was a solid shift at any rpm - great when drag racing but it deffo wouldn't suit a Bristol. If I do actually end up putting a GM 200-4R in my 411 I'll need an uprated one (to take the torque) but want it with a stock feeling shift - all the trans companies I've looked at build them for hot rodders & bracket racers, so they advertise much firmer shifts.

[Geoff Kingston]

My 411/3 sold some years ago did not have any half throttle kickdown response but when I decided to fit an Edelbrock Performer Carb and Manual choke set to the car and adjust all the linkages as the installation instructions suggested all was well and I had full and part throttle kickdown no expensive mods and I remember reading years ago that Bristol had set up the linkages on their cars of this period to exclude the half or part throttle kick down both of which operate on my 603.
This video which I have just come across may offer some insight into the issue or not as I got distracted when viewing it but but decided to post the link anyway as we may all learn something.
Geoff.

https://www.motortrend.com/how-to/th...-down-linkage/

[AndrewA]

The article highlights the problem I had on mine when it came back from having the selector fitted.
My gearbox is wider than original and Martin Barnes got round this (when he did the conversion nearly 23 years ago) by engineering in a bit of flop (not slop!) into the rods and linkages and extended a few others. The garage tightened everything up before they gave me the car back and removed the flop hence no kickdown. It took me about two hours of looking and thinking but once I'd understood what he'd done and why it was a five minute job to put a bit more slack into the system.
I did seriously consider the Lokar solution - you apparently do need to use their gas/accelerator pedal as well - or so I've read - but then local mechanic pointed out that what I've got works perfectly well so why not stick with that - at least until current setup fails - so I am!

[David C]

Here is a picture to illustrate the difference Andrew refers to. The gearbox tunnel was originally pretty much symmetrical. The hole for the linkage at the top of the red area has had to move outward about 2 inches to get a clean vertical drop down the side of the transmission.
Modification to the tunnel and re-engineering the linkages is about the most time consuming part of upgrade to overdrive.

Many thanks to Geoff for the helpful link on how to adjust the kickdown.

[David C]

With any luck the picture is attached this time...http://www.bristolcars.info/forums/a...1&d=1697129123