Shift linkage - encourage spring-back to center pos.

[RussMcB]

Fishing for ideas.

This winter I'll be redoing my shift linkage. I'm in the early planning stage, considering various methods.

One thing I'd like to address is ensuring the shifter returns to the center position after the shift. I assume springs of some sort would do it. Would like to hear ideas or see pictures.

I'm open to low cost paddle ideas, too (low cost = something I can make myself).

Thanks in advance.

[Dennis Tapp]

Russ, I attached some pictures of the shift linkage Pat Prince built and installed on my car. I picked it up last week in Sterling. It is a bump shift, did not like the paddle on a kart so I did not want one on a car. You should be able to copy. It does have springs to center. This is hooked up on my car to upshift by pushing forward. My first go kart was that way so I am stuck with this for life. More people seem to go the other way. If you wanted the oposite you would have the shift lever on top of the shaft insead of down as on this car. Russ, If you want any other pictures from different angles let me know and I can e-mail to you. Dennis

[outlawzracing]

That looks great. Where did you get the shifter cable? thanks

[Dennis Tapp]

Any cable shop can make you one. It is an industrial cable, you just need to know what length you need.

[formulasuper]

Fishing for ideas.

This winter I'll be redoing my shift linkage. I'm in the early planning stage, considering various methods.

One thing I'd like to address is ensuring the shifter returns to the center position after the shift. I assume springs of some sort would do it. Would like to hear ideas or see pictures.

I'm open to low cost paddle ideas, too (low cost = something I can make myself).

Thanks in advance.

I've said it before & still believe the way to go on shift linkage for a motorcycle powered car is push/pull rods. On my Fireball Ralt/Hayabusa I used the original Ralt shifter handle assembly & push/pull tube linkage all the way back to the engine. I then used a bellcrank tube mounted with bearings on each end to transfer the motion to the left side of the engine/tranny where the foot shifter shaft is located on the tranny. I connected the bellcrank to a modified original foot shifter lever with a short rod. All connections are accomplished using small (5/16" & 3/8" shank) spherical ball threaded rod ends which gives it total adjustability. There is no friction & therefore no resistance to return to center. Pushing/pulling the shifter handle feels exactly like push/pulling on a foot shifter lever.

[RussMcB]

I agree that rods should give the best feel. That is Plan A for the winter re-do. However, I think it will be a challenge to route the bars in my car, especially the cross bar from the right to left side of the car. Not impossible, but everything is so tight & cramped in my car.

A lot of people have trouble-free cable linkages, so I don't want to discard it as an option. If I (ever) decide to make a paddle shifter, cable(s) will probably work better with that.

Thanks for the ideas. They're appreciated.

[Billy8910]

To make the shift linkage with push-pull rod even more rigid and slop free, I have been considering a left hand shifter handle. Then its a straight shot back to the shift shaft. Wonder if I could get used to shifting with the left hand? Think of a right hand drive car.

Billy

[RussMcB]

I think that is an idea worth considering, and I think a driver could get used to it. I discarded the idea because the left hand shifter area didn't have enough room in my car. On the right side, Van Diemen made more room with a bulge in the body work, so I left it there.

[formulasuper]

To make the shift linkage with push-pull rod even more rigid and slop free, I have been considering a left hand shifter handle. Then its a straight shot back to the shift shaft. Wonder if I could get used to shifting with the left hand? Think of a right hand drive car.

Billy

If you checked my linkage you probably wouldn't think you could make one more rigid & slop free. With good rod ends & good bellcrank bearings there is no place for any slop. Aircraft designers use this system & they are quite concerned about slop.

[John]

My AMAC used rods and we had to have special plastic bushings carrying the rods and every thing had to be free or it would bind and not return
The way to get the shift linkages to work is to make sure that the system is free. The less expensive rod ends work best as they impart less drag, I use a cable shifter in my Maloy now with inexpensive rod ends at the ends, and it works well, keep the bends to a minimum and the shifter will work fine.

[cparsons]

Russ, I have spent a couple weekends playing around with electric door lock actuators for use as electric shifters. The door lock actuators are bi-directional solenoids so they will shift up and down. The spring tension of the trans does return them to "center." And the door lock button can be used as the shifter button. I am using 2 "nose to nose" with a short extension on the original shifter arm. I haven't found the sweet spot on the shifter extension yet but am SO close. I wish they had just a little more "ooomph" Neutral presents a slight problem, but I think I can solve that with a 3d solenoid to act as a stopping point and have a separate button for neutral.
I used GMC actuators. If the shifter doesn't work I can always use the parts in my van.

[stephen wilson]

Chuck, you should contact JD King about the electric actuators. He tried using them also, and last I heard he was having trouble with them. I'm not sure if it was the amp draw, or intermittant actuation, as you say, no oomph.
Steve

[RussMcB]

Over on the D Sports Forum someone shared their opinion that the reason they didn't like electric actuation (or any automatic actuation) was because the driver has no feel or physical confirmation that a gear has been selected.

Just passing that along. I can't comment on it because I don't know how true it is.

[cparsons]

I am going to hit them with 24 volts to see what happens, if I can remember my Electronics 101 theory. I plan to use a gear indicator from Accumen or Datatool(?) but now understand that they may NOT indicate a gear change until AFTER the clutch is released. That might make for a big oops. (Not that I never missed a gear before...)

[cparsons]

Thanks guys:
Stephen, can you provide contact info for JD?
Russ, I checked the sports racer site, Good stuff there, thanks.

[sidney]

I am going to hit them with 24 volts to see what happens, if I can remember my Electronics 101 theory. I plan to use a gear indicator from Accumen or Datatool(?) but now understand that they may NOT indicate a gear change until AFTER the clutch is released. That might make for a big oops. (Not that I never missed a gear before...)

You gotta be careful using more voltage to get more power. The problem is the coil is not designed to dissapate the energy you are putting through it. It will work for a brief period of time, but then overheat. We have a similar problem when customers try to use a 12V coil with a 24V system in the hydraulic world. It works great the 3 times the guy in the shop tries it, but then the customer gets really angry when it wonly works for 10 minutes.

[stephen wilson]

Chuck, a link to JD's email can be found under the members list, search under J.D. King. He also posts in the FF section.

[sidney]

I found a post either here or in the sportsracer site that mentioned Kevin Mitz at Rennwerks had some Stohr paddles for sale. I got one from Kevin for a very reasonable price. Russ, or anybody else may want to give him a call. Very nice guy to talk to. He was very excited about FB. He also mentioned that he had a number of assemblies available. Good Luck on your winter updates.

[10rmotor]

Over on the D Sports Forum someone shared their opinion that the reason they didn't like electric actuation (or any automatic actuation) was because the driver has no feel or physical confirmation that a gear has been selected.

Just passing that along. I can't comment on it because I don't know how true it is.

Don't know who said it either Russ but I totally agree. I have a linkage setup with right hand shifter, a link going back to a cross shaft, and another link continuing rear to the trans shift lever. When at speed having "feel" isn't too critical, but when slowly rolling when in the hot pit lane for example, and trying to get into neutral feel really is important. Electric or air actuated shifting just doesn't give you this. I'm not a fan of cables either because if the routing of the cable is too tight it can stick or cause friction. The return springs in the shift drums of the new motors are not as stiff as older motors and don't have enough force to return the shift lever to the middle position. Also, if improperly routed to close to heat sources, cables can melt.