Throttle coupling replacement

Davedstone

Member
Any advice welcome on this one. Drove my car over the weekend for a short journey to test it before a longer drive over the weekend and to cut a long story short, the nylon throttle coupling broke (accelerator pedal link to carburetters) and I managed to rig something up in order for me to drive it back home. (less than a mile) I ordered a replacement coupling which arrived and I went to fit this, but not able to access this due to lack of access due to the carburetter adaptor and tie bar being in the way. I managed to get the coupling in place but I am unable to insert the split pin to secure the shaft connecting to the accelerator pedal.

The manual suggests keeping the carburetter (twin) attached to the inlet manifold and to remove as one unit. Has anyone else had to replace this coupling?
Is there another way?
Is it not possible to just remove the carburetter away from the inlet manifold?
Thanking anyone in advance.
Regards,
Dave
 
If this:

View attachment 20217

Is the part you mean you should be able to fit it after removing the air cleaner assembly.
Yes this is it. I removed the air cleaner which allows a small amount of access, but not enough. My fingers need to be 12 inches longer. It's as if I have to remove the link plate for the carburetters or even the tie bar above. I managed to get the coupling on, but not able to fit the split pins and of course without these in place, it won't be long before it breaks. Too dark now to do anything, but will take another look tomorrow afternoon.
Thanks for your swift response. Very much appreciated.
 
Did mine about 8mths ago.
Used a little aggression and pushed the two rods apart, got the knuckle in Ok and just wriggled and jiggled the pins in place.
Was on a V8 though.
I keep a spare in the glove box , as after 50 years of use I dont want to be stranded again.
 
Did mine about 8mths ago.
Used a little aggression and pushed the two rods apart, got the knuckle in Ok and just wriggled and jiggled the pins in place.
Was on a V8 though.
I keep a spare in the glove box , as after 50 years of use I dont want to be stranded again.
I was struggling last night and tried pushing one of the pins which was not totally aligned correctly which then folded in on itself so a trip to get a few more pins from Alfix fasteners this morning with another crack at this later. Oh the joys!
 
Haha -I got caught with that too. I used a common garden variety panel pin, bent to stay put after driven home with a 5kg mallet.
 
Haha -I got caught with that too. I used a common garden variety panel pin, bent to stay put after driven home with a 5kg mallet.
Lucky for me, I was less than a mile from home so managed to gerry rig it in order to get back. Try and do that on a car will ECU's all over the place. You can't beat mechanical things.
 
The throttle coupling failed on me this week. Second time in near 30 years of having the car, but as usual at a bad time.

FYI, I bought a replacement from Wins and noticed that Geoff now has a batch made in US and notably more robust than the OEM dimensions and a different resin material.
I wondered if these are unique to Rover V8s or common to other similar twin carb set-ups. I thought perhaps the dimensions could be simply enlarged considerably more to avoid further the risk of splitting or failure local to the split pin housing. There's nothing located near to limit their dimensions.

1708022144404.png
 
Maybe you could design a beefier one and have it 3D printed out of a tougher material than the original item? I think our fellow P6er sdibbers over in the US does low volume 3d print stuff, doesn't he?
 
Nice idea - that shape would work well for 3D printing. I would hope 3D print resin is Ok for the temp extremes it has to work it - hot engine or freezing cold days ..
For my case, I pumped the pedal a couple of times before starting on a cold day and snap - split down the middle ..
 
Last edited:
I don't really know much about 3D printing, but I gather it is possible to print metal (!!!) and actually have it be quite strong these days.
I should probably keep a couple of spares of that part in the glovebox, having also had them fail on me on two occasions. The original ones go yellow and become brittle over the decades.
 
yep - as you say decades - I guess the idea was that they should need to work for a few years. I'm also finding similar things now failing after multiple decades, eg things with spring clips, plastic light fittings, even the alternator mounting arm failed in a classic fatigue crack only last year ..
 
We designed and supply these for Geoff at Wins International. They are printed in nylon 12 with an improved design that addresses the usual failure point. They are suitable for the TC and V8 models (and the SC if used there - I’m afraid I haven’t a reference for the single carb setup).
 
I don't really know much about 3D printing, but I gather it is possible to print metal (!!!) and actually have it be quite strong these days.
You can print in metal, at a cost factor of about 5-10x the price. Nylon makes a good material for this as it’s self lubricating, its failure mode is to bend and not crack (unlike the original POM/acetal plastic used). Bear in mind the originals lasted for about 45-55 years before failing, so I think that’s a reasonable service life :).
 
I thought perhaps the dimensions could be simply enlarged considerably more to avoid further the risk of splitting or failure local to the split pin housing. There's nothing located near to limit their dimensions.
The reason we don’t make it just thicker is that the plastic can distort during printing when it’s a heavy cross section. This can cause things to become stiff around the drive pins on the torque rods, which could cause a sticky throttle. Or loose around the pins giving a slack area of lost motion in the throttle linkage. Just to explain the reasoning of the design decisions taken.

If you’d like to look at the technology used to producing these parts google multijet fusion printing.
We’ve used this same technology to make intake runners for tuned Alfa Romeo Busso V6 engines. We know of one set now that has 15,000 miles of use on them and they still perform well.
 
You can print in metal, at a cost factor of about 5-10x the price. Nylon makes a good material for this as it’s self lubricating, its failure mode is to bend and not crack (unlike the original POM/acetal plastic used). Bear in mind the originals lasted for about 45-55 years before failing, so I think that’s a reasonable service life :).
Ive had to replace mine once recently. I think after 50 odd years of service ,Im not going to grumble. The only piss off was it broke on a busy motorway and a long way from home.
 
Back
Top