Short Shift kit eliminate gear grindage?

[Avezoh]

Raced a Toyota in the hills the other night and did pretty well- beat him handily by winding the engine out to just below the ignition cut-out and gassing it through the bends. Here's where the car wasn't so impressive. When trying to down shift from 5th to third- ( there are times where you slow enough that bypassing the next lower gear is desireable ) get the usual balkiness where it's hard to find the lower gear(s). In speed shifting up from second to third though always get a slight crunch as though I'm beating the synchronizer's ability to synch up with the next higher gear pair. If I keep the revs down there's never a problem.
My analysis is that this is true between second and third because they are accessed via the shifter diagonally across the "H" shift pattern and that the already present slop in the remote linkage aids tyhe problem. My guess is that speed shifting at higher r's manifests in "beating" the synchro because the inaccurate linkage probably doesn't positively select the synchro and next higher gearset completely and higher rpm's bring out the synchro falling down on the job. If I'm correct, does the short shift kit ( along with adjusting the linkage to fully engage each gear ) eliminate what appears to be an inherent tendency to slightly grind the synchro between second/third on up-shifting at decent revs as well as the difficulty to downshift out of fifth to the lower sets?
Thanks in advance.
Steve

[petrified.rabbit]

just a question, how sloppy is your shifter? and what are you miles, year?

the actual front back pivot is two (or three depending on how you look at it) plastic cups, you can adjust them slightly to be preloaded, but i think it would cause very fast wear. Also how is your clutch work? are you doing one firm push? ae you hitting it into the next gear at the floor?

the transmission is extremely notchy, unfortunately the shifter is so sloppy. It does tighten up with the short shift kit, but it really sort of make it "harder" to put in gear on faster hi rpm shifts, not grinding so much for me, but force like i am making the syncro work faster than i can (same as your conclusion it sounds)

[Avezoh]

Shove the clutch in all the way and in one firm movement. However, sometimes I up-shift motorcycle style and push into the next gear ahead of the clutch action- is actually smoother and more positive. The mileage is 29685 and the year is '08. Play is pretty much side to side- quite sloppy.

Only notchiness I notice is on the up-shift between 2 and 3 at above 3000 r's. It's only a slight graunch- reminds me of old British sports cars like MG's and Trumpet 6's when speed shifting- could beat the synchros on them too. Of course, I atttributed that to the old truck transmissions they were running...

Will experiment also with a synthetic aftermarket trans fluid next. So, are you saying the kit may exacerbate the notchiness?

Steve

[petrified.rabbit]

I wont say it will make it better or worse, from your description i honestly think your feeling the syncros. And you also know the short shifter doesnt change the syncros. But the adjusted length of a short shifter does tighten the side to side some. they too have plastic caps which are some what sloppy, i think you can turn the rod pivot to preload them as well. That would make it better, and is essentially what the short shift kit does.

I guess I need to be careful calling it notchy, as everyone will have a different definition of that. With the short shifter i can definitely shift faster, the shifter (once adjusted) is more precise, but if your really pushing the car and fast shifting you will still be fighting the syncros just like on the oem shifter, but you be doing it faster.

With your mileage and year you should still have just the factory slop, i don't think anything is worn out yet. It is definitely a design that could be improved upon.

[Avezoh]

Agreed. Wonder if replacing the plastic cap/joints with rod-ends would allow enough pivot to mimic stock but would eliminate wear issues ( rod-ends with dust covers- not the open racing spec ). Adjusting the linkage and seeing ( removing the drain cover ) that it properly fully engages each gear would definitely help. Trying a different gear oil ( just putting in clean, fresh, contaminant-free fluid would probably be a huge improvement )may be a factor as well.

Steve

[xintersecty]

When I drive with my hand on the stick, I notice a feed back from the engine. When I accelerate, the stick pushes back in my hand, and when I let off the accelerator, the stick moves slightly forward. I can tell the engine is shifting in its mounts. I saw a mod to stiffen the engine mounts, would that help this feeling in the stick? Or this feeling in the stick a way of telling I should check my engine mounts.

Rabbit you made the shifter kit. I think I saw that in an other thread. Do you still have any left?

[Avezoh]

When I drive with my hand on the stick, I notice a feed back from the engine. When I accelerate, the stick pushes back in my hand, and when I let off the accelerator, the stick moves slightly forward. I can tell the engine is shifting in its mounts. I saw a mod to stiffen the engine mounts, would that help this feeling in the stick? Or this feeling in the stick a way of telling I should check my engine mounts.

Rabbit you made the shifter kit. I think I saw that in an other thread. Do you still have any left?

I was thinking about the engine moving about as part of the equation. Come to think of it- the instances where I've noted, and even tested for repeatability, the "synchro beat" has been on uphill or downhill sections where the engine would surely be moving forward or backward on the mounts. Haven't tested on a flat section yet. Definitely know the engine moves quite a bit as I have to modulate ( feather/back-off/adjust/etc. ) the clutch/throttle on even mild take-off to keep the front wheels from stuttering.
Rabbit? What's your input? And yes, you got any kits left? Wanna get one.
Steve

[petrified.rabbit]

the was a member here who had a bad mount and when he hit the gas it would pull the car back out of gear.. so movement is a factor. Aside from a complete mount redesign (oem mounts use two horizontal bolts the fact each other allowing the whole engine to pivot and leaving all the work to the dogbone). I think the best solution is to space out the dogbone to limit its torque deflection. but it might not be the solution, because honestly i have not looked to see if the torque pushes the mount or pulls it. I am assuming pushes.

I dont currently have any short shifters ready to go, i was going to order the cad drawn plates with the next set of coilovers. but they have been sitting here a while. I do have an arm here, so once i get them, i can modify it and ship it out pretty quick.

replacing the plastic cup joints would benefit the system, but you would need to make custom arms on the linkage as well. I have those pieces of the shift linkage, and have been thinking about trying it, but was waiting for my shifter to wear out, as its my daily i cant keep pulling off the road for all the projects i have planned for it. VW used a similar set up in the 80's as our shifter and they have many heim joint replacement kits that greatly improve shifting. So it would work. but you would need to make two custom upright arms on the linkage to support the use of the arms. not a big task by any means but still more than just buying the right size and sticking it in the current system.

[Avezoh]

Yes, the old you change one thing and then three things interconnected have to change... For this application time and the biggest effect for the simplest change would pay the largest dividends in time vs. effect. I've seen what one owner did by filling in the mount voids with a rubberized epoxy IIRC- though that is a little too "woodshed engineering" for my taste. Analyzing whether the mount is compressed or operates in tension would be the first step- and you obviously have been thinking about it already. Wonder if making or extending the bracket the mount and/or dog-bone attach to ( the mount attaches to the dog-bone? ) and attaching a stop bolt on one side to limit the mount movement or dog-bone deflection might work and would be a simple modification. I'm trying to picture how the dog-bone is situated with the mount and how spacing it out further would limit deflection?

Steve

[petrified.rabbit]

simply put it looks like either a plunger(if a compression mount) or a hook (if a tension mount) so moving the mounting plan to stiffen it would help which ever direction it needs to go.. but it is only possible to move toward the engine. since it is unter the axle. and the axle spins forward at the top the it should be a compression mount. the other problem is the single horizontal bolt through it as well. all the joints are pivots in the same direction as the axles..



the window weld, or even poly mix filling the mounts is as good as or even better than the prothane inserts that are out there that just slip into the openings.