Rover V8 kickdown linkage

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ratwing
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Rover V8 kickdown linkage

Post by ratwing »

I'm looking for the three parts at the inlet manifold end, the rod/lever that pulls the kickdown cable inner, the bracket/bearing that supports the back end of the rod/lever and the bracket that holds the kickdown cable outer. Parts from any Rover V8/BW auto would do if anyone's got them?
King Herald
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Re: Rover V8 kickdown linkage

Post by King Herald »

I made my own brackets when I built a RV8 years ago. It had to have a slotted fitting in the end to allow the throttle to move freely without pulling the kick down cable until just before wide open throttle.
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1130cc
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Re: Rover V8 kickdown linkage

Post by 1130cc »

For years, I have been thinking of making mine electronic, activating it using a button next to the throttle.
The button would trigger a ram, which in turn pulls the cable.

I was going to use a boot release plunger, that I have lying around, but it would need a constant power to it, rather than it just trigger and release.

Maybe I will get around to it one day :)
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ratwing
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Re: Rover V8 kickdown linkage

Post by ratwing »

This is for a ZF4HP22 (with 4HP24 internals) so the cable needs to move with the throttle. I don't have my notes to hand but apart from extending the lever a little (IIRC BW35 cable stroke is 35mm, ZF4HP is 39) the BW parts will bolt straight on and do the job nicely.
I'd prefer to use the Rover/BW parts just to save having to make them and fortunately it doesn't look too difficult to do because they don't seem common and I haven't managed to get hold of them so far.
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1130cc
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Re: Rover V8 kickdown linkage

Post by 1130cc »

The kickdown only operates on full throttle, so the addition turn of the throttle to initiate kickdown is probably less than 5 degrees.
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ratwing
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Re: Rover V8 kickdown linkage

Post by ratwing »

I take your points but on the ZF as well as actuating the kickdown valve near full throttle, the cable varies throttle pressure in the valve body all throughout it's travel so it's important to get the whole range of movement right to avoid clutch slip or excessively hard or soft gearchanges that ends up destroying the gearbox.
It's looking more likely I'll end up making the linkage, all the Rover V8 engined vehicles I know of that used the model 22 had fuel injection so I'm left looking for very much older and as it turns out, harder to find V8/BW parts.
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Re: Rover V8 kickdown linkage

Post by Barneyb »

1130cc have you thought about a cheap servo motor, you can vary the angle to what you want by varying the pulse. If you do anything with microchips it could be quite easy, pulseout to a logic gate mosfet then to the servo.
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Re: Rover V8 kickdown linkage

Post by Ghoulie »

Looked at this from Rimmer Bros when I was sorting out recon gearbox for Misty Blue - https://rimmerbros.com/Item--i-RA13234WDKD

Marc had disconnected the kick down cable on old box. (Said Misty was trying to kill him with kickdown on - his idea of riding seemed to be throttle full open - back end just spun round !!) Wasn't sure if the fittings were there or not. When mechanics came to fit the box - fittings were there still - but from the previous 4 barrel Holley carb set up (prior to Marc putting me a 4 barrel Edelbrock carb on) - so they fettled some missing linkage for me. Marc must have had the cable tension all wrong.
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Re: Rover V8 kickdown linkage

Post by King Herald »

Ghoulie wrote: Mon Mar 25, 2024 5:29 pm Looked at this from Rimmer Bros when I was sorting out recon gearbox for Misty Blue - https://rimmerbros.com/Item--i-RA13234WDKD

Marc had disconnected the kick down cable on old box. (Said Misty was trying to kill him with kickdown on - his idea of riding seemed to be throttle full open - back end just spun round !!) Wasn't sure if the fittings were there or not. When mechanics came to fit the box - fittings were there still - but from the previous 4 barrel Holley carb set up (prior to Marc putting me a 4 barrel Edelbrock carb on) - so they fettled some missing linkage for me. Marc must have had the cable tension all wrong.
I only hit the kickdown at full throttle once, in my RV8 hot rod, then I went home and disconnected it. The bang and jerk of it downshifting scared the cack out of me and I thought I’d broken something. It was a light car, 1000kg.

If I wanted to shift down I’d move the lever, after that.
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ratwing
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Re: Rover V8 kickdown linkage

Post by ratwing »

This is a late reply but it's just in case anyone searches with a similar question.
I'm now changing the twin SU's for an Edelbrock and it appears straightforward to make a bracket and alter the length of the nearside levers to pull the kickdown cable. Nice and simple, no extra rods/joints/bellcranks etc needed and gives a minimum of bends in the cable run too.
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