Shifter question

[7tooZ]

While cleaning up my transmission for installation I was pondering this.

If i drill a new hole where the X is, wouldn't that create a shorter throw. Would it raise the pivot point?

What problem might it create?

Need help from you engineers.

 

 

Don's iPhone using Classic Zcar Club mobile

[siteunseen]

No engineer here but the ball/cup at the bottom of the shifter would be too high and not engage the gears. A ZX shifter with the plastic sides would be a short throw on a wide B.  I had one on mine for a minute, tore the inner rubber boot and my knuckles hit the radio.

[7tooZ]

This is a close ratio from 83 Z. My thinking is not to raise the shifter only to raise the pivot point. Isn't that what a short shifter does?
I would have to drill both pieces.


Don's iPhone using Classic Zcar Club mobile

[Captain Obvious]

Yes, it would shorten the throw above the pivot by increasing the throw below the pivot. If the change in pivot location is confined only to the locations you have shown, then I can't imagine any other problems that could cause. All the other geometry should be the same before and after.

Looks like there is plenty of room on the ears, but is there really enough metal on the shift shaft to put a new hole?

[7tooZ]

There seems to be on this shift lever. That is what would dictate the maximum amount I feel would be safe. Plus I would be concerned about making the throw too short.

I was looking at the short throw shift kit on our 2.4 RS subie and it only raised the pivot point about 3/4 inch.

Plus I can't see how it would affect going back to the original point if needed.

Would you drill a small pilot hole and then enlarge increase the bit size?

 

 

Don's iPhone using Classic Zcar Club mobile

 

[Captain Obvious]

if you're really interested, you could calculate the change in throw. It's linear and straight up ratiometric.

I would definitely drill a pilot hole first, for two reasons... First, just to ease the drilling process with the larger bits, but also to double check the concept and look for issues before it's too late. You could walk the small hole around a little with a file if necessary to tweak things into place before you finalize with a larger size. The size of the final hole is important though since it needs to be a good fit with the shifter bushings, right?

If the new holes don't overlap with the old holes, then you could always just go back to the stock location without a problem. Call them lightening holes to decrease mass and increase shifting speed and gas mileage. 

[Zed Head]

You have to change the hole in the lever, not the ears, to change the ratio of travel between the top of the lever and the bottom of the lever..  Travel of the bottom of the lever will be the same, it will just be higher up, if you only drill the transmission ears.  The bushing at the bottom of the lever slides up and down in a cylinder as the lever tip moves back and forth.

Another way to get a shorter stroke is to cut the top of the lever down.  You can simulate that by holding  the lever lower when you shift, if you want to gauge the increase in force needed.  The downside of the short-stroke.

[7tooZ]

Ops. Was I wrong because that make no sense to me. The bottom of the lever has to stay static to even work. I may stupid about this but it seems to that the fulcrum has to move to gain movement on one end and shorten on the other. Drilling thru both and moving the pin higher makes more movement to the shift mechanism in the trans. Right?
If that works then shorting the lever is still an option which is what I did on my series I trans.
Love the input to help me get the thinking right.


Don's iPhone using Classic Zcar Club mobile

[Zed Head]

The fulcrum is the pin in the hole in the lever.  If you just move the holes you're moving both the fulcrum and the lever.  No effect, except pressing on a different part of the same object.

[7tooZ]

Hummm guess it won't work because if I drill holes and raise the lever the lever moves out of the transmission mechanism.
Anyone see a reason NOT to try it? I Can always move the pin back to the original position.


Don's iPhone using Classic Zcar Club mobile

[Zed Head]

You don't see how the top of the lever will move the same distance no matter where you put those holes?  You'll be moving the lever and the fulcrum.  You need to move the fulcrum relative to the lever.  Not relative to the object being moved.

The point of the short shifter is to move the internal mechanism the required distance (the required distance stays the same) with less movement at the top of the lever.  If you don't change the ratio of the top of the lever to the bottom of the lever (moving the fulcrum) then by definition, it won't work.  It won't have any effect.

[Mark Maras]

I believe you'd have to cut the lower end and weld in a piece to lengthen the shifter.