I’m finishing up a rebuild of both of the carburetors on my '50 '120 but have yet to trim the replacement throttle shaft ends to length. The original throttle shafts easily had 0.015+" of lateral play so now they’ve been rebushed back to specs also. As the original tension type of return spring makes for a strong downward force on the shafts and thus, accelerated wear, I’ve been thinking of doing away with it and replacing it with a torsion type of return spring like on MGA’s, Triumphs, Healey’s etc. Has anyone ever gone this route before? Also, as I’m not familiar with later carbureted Jag’s, when did they go over to a later set-up?
Any thoughts on this? The only snag I see is there possibly being not enough force to return all of the foot pedal linkage back to position. Why Jaguar didn’t use a cable instead all of those rods and bell cranks is beyond me, but probably beside the point here.
Here’s a picture of a pair of old MGA carbs. Notice the return springs on the throttle shaft ends:
Thanks. Looks like I missed that thread. I don’t do any racing with my car but I am mostly interested in minimising shaft wear as much as possible. Thus, the interest in this possible modification.
The pivot bolt at the base of the accelerator pedal might be too tight or in need of cleaning or lubrication. When that’s the case, too stiff a return spring may be found on the carb linkage. That in turn puts excessive wear on the throttle bushings. Especially on XK120s with only one return spring.
