mechanical throttle linkage, what's the problem ?

[bartsscooterservice]

Everybody knows the problem: it's really hard to drive away without flooring it right away and having a wheelspin. I lubed everything, I adjusted the play, even did the bellhousing modification, that helped a little, but still I have problems driving away normally. What's the problem here ?

It's driving me crazy..

[AZ-240z]

Bart,

It is a design short-coming in the geometry of the 240z throttle linkage, and plagues every car. I have heard that it is possible to solve

this problem by re-configuring some of the linkage attachment points, but I have not done any further investigation.

I'm sure someone here has attempted to do a modification to the linkage to allow for a smoother accelerator pedal application.

Dan

Edited August 22, 2013 by AZ-240z

[siteunseen]

It is a design short-coming in the geometry of the 240z throttle linkage, and plagues every car.

Boy oh boy that makes my day. Same problem here too and was on my short list, to do very soon. Mine starts "hopping" when I try to leave out easy from my driveway.

Edited August 22, 2013 by siteunseen

[zKars]

The common fix involves reducing the included angle of the two bell crank arms from ~90deg to ~50deg or so. There is a thread on here somewhere about this.

Just cut the mounting tube in half, rotate and re-weld. Change length of the upper rod end to match.

You could also convert to cable throttle, the best solution in my mind. Depends on whether original look or vastly improved functionality is your goal.

[Mikes Z car]

The PO for my car bent the arm on the linkage to help with throttle jerk but it doesn't get rid of the prblem completely. I sure remember my other 240Z from 30 years ago taking off fast from every start. A passenger mentioned it to me once. (Is that why you like these little cars?)

More info here:

Throttle jerk fix - Blogs - Classic Zcar Club

Edited August 22, 2013 by Mikes Z car

[240260280z]

Karl & Dan got it here: Accel. Linkage Fix

I recommend taking the slop out of the linkage and lubricating as a first step.

FYI Some of the linkage rods are threaded for doing this.

Hardway and I cut and chased new threads on his to improve performance.

[240dkw]

Here is the post

 

[Mike W]

So unless you have an aversion to moving away from stock, which is a perfectly valid reason to stick with the OEM setup, then moving to a throttle cable is the best and only way to go in my opinion. I run with triple Webers and have for years, and constantly fought the "drivability issues" that the OEM linkage introduced. I know that some have been successful with getting the OEM setup correct, but no matter what I tried I could never get there.

So I went with a Lokar universal cable setup. It did take a little modification at the pedal to get the connection right and I also had to figure out the connection to the throttle rod for the Webers, , but enough other people had done this, I found numerous choices.

I wish I had done this years ago. My car is some much more drivable and responsive it just makes you want to drive it more as I am not constantly fighting the jerkiness, etc. And the return to idle is always perfect now.

This probably ranks in the top 2 improvements I have made to my car and could be #1. I'm so happy with it that when I had my car painted last year, I had the shop totally remove all of the brackets in the engine bay associated with the OEM linkage. Needless to say, I'm never going back.

Mike.

[grannyknot]

Bart, Lokar cable. Smooth and simple,

[Zedyone_kenobi]

I do not find this to be a fault with the Z. My Z had this exact problem when I first bought it. It was quite bad actually. When I got the SU's rebuilt at Z therapy, It came back with new linkage rods on them. The cars problem were 100% gone. All of the parts were bone stock. Nothing was cut, bent, modified or any other creative bandaid. I am just saying that if the parts are in good non worn out condition, the throttle will be perfectly OEM.

I would recommend calling Z therapy and asking them how much it would be for a complete set of new push pull rods with new ends on them

I think if you get that, and remove all the slop, you will see your problem goes away.

Moral of the story, when the car was new it did not have a sticky throttle, so return it to new....

Or you can get a lokar cable, as it work very well just as Mike said.

[bartsscooterservice]

I want to keep it Original, so cable is no option. I did the bell crank mod, and for a while that seemed to help but the problem is back. @ Kenobi : I was thinking the same way, the problem wasn't there when new ! It must be wear.. or a little sticky butterfly valves in the idle/lower part ?

[bartsscooterservice]

mm, so the problem must be in the butterfly shafts on the carbies...