914World.com > Improved shifting for side shifters, bolt on? Maybe.

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Dr Evil

Apr 14 2014, 10:14 PM

I have had this though for a long time to try and remove as much slop as I can in the shifting system. The tail shifter is a bit trickier, but not impossible. I have a side shifter in my new 914 and so, while I build up a transmission for it to drive to Hershey this weekend (this will be the raffle transmission, BTW. Trial by fire!), I decided to see how simple it would be to remove some of the slop.

First, see how much of a gap there is between the shift selector comb and the rod. Click to view attachment

This is a huge amount so any bit that can be removed should be an improvement.

Step one was to add material to the sides of the comb faces (Yes, Scotty, I welded). Then, I hand filed the faces and re-formed them to a specific profile. The metal that was added was hardened and a real bitch to file. I figured it was worth it.

The end result was a much tighter fit.
Click to view attachment

There are a few parameters that I will not go into that need to be respected to get this to work, but the preliminary results were nice on the bench. With the material added and profiled on the faces, the stick throw fore and aft to select gears decreases significantly. There is still refinement that needs to be done on the profile, but so far the preliminary results are encouraging.

Next, I will build a jig so I can directly observe and adjust my profile. And I will also be able to see where I can add material to take up the slack that one feels when they are in gear and can wiggle the stick back and forth.

Once I get this prototype done and tested, I can do this treatment to any side shift console on an exchange basis and it will be a quick bolt on improvement (I hope).

boxsterfan

Apr 14 2014, 10:23 PM

'73-914kid

Apr 15 2014, 12:05 AM

What kind of clearance are you aiming for between the comb and the shift fork selector? .08-.1"? Seems like too tight might be a problem, but I love this solution... The never ending process of making these cars shift better should interest a lot of people..

HalfMoon

Apr 15 2014, 01:18 AM

bulitt

Apr 15 2014, 04:37 AM

Seems the play may be "designed in" to compensate for movement of the engine and trans under braking and acceleration ? But finding out how much is too much is trial and error (which I assume is what you are trying to determine). Could be dependent on the condition of your motor and trans mounts also.

Dr Evil

Apr 15 2014, 07:16 AM

QUOTE('73-914kid @ Apr 15 2014, 02:05 AM)

"Seems like too tight.." This is why I actually built and tried it. As mentioned, it works. Clearance will be my secret.

No armchair engineering here. Do or do not, no guessing.

IanS

Apr 15 2014, 09:34 AM

So you say this can be similarly engineered for tail shift? Do you have access to a tail shifter to test/engineer?

CptTripps

Apr 15 2014, 09:54 AM

QUOTE(IanS @ Apr 15 2014, 11:34 AM)

So you say this can be similarly engineered for tail shift? Do you have access to a tail shifter to test/engineer?

If there's one thing I'm certain of...it's Dr. Evil's rolodex of people with tail-shift transmissions.

mskala

Apr 15 2014, 10:43 AM

QUOTE(IanS @ Apr 15 2014, 11:34 AM)

So you say this can be similarly engineered for tail shift? Do you have access to a tail shifter to test/engineer?

For the -6 version of the tail shift, I did basically the same thing last year:
914-6 shifter slop improvement
It didn't hurt, but I didn't notice any real improvement either.

Dr Evil

Apr 15 2014, 10:53 AM

For a tail shifter you would need the external shift rod, too. You have to add material to the ball. Then, you have to take the whole stack out to get to the internal shift actuator and add material to that. The real problem with the ball on the inside actuator is you have to put some material in a specific place on it (hard to describe) so that you do not get it wiggling side to side when it is in gear. To make a tail work as well as I can make a side.....it would be a task. I am interested in doing it, but do not have a car with this set up. Also, side is sooooo much easier.

Dr Evil

Apr 15 2014, 10:59 AM

QUOTE(mskala @ Apr 15 2014, 12:43 PM)

QUOTE(IanS @ Apr 15 2014, 11:34 AM)

So you say this can be similarly engineered for tail shift? Do you have access to a tail shifter to test/engineer?

For the -6 version of the tail shift, I did basically the same thing last year:
914-6 shifter slop improvement
It didn't hurt, but I didn't notice any real improvement either.

Mark, without addressing the internal shift mechanism you will see limited results. The problem with the tail shifter is majorly within the box. If you saw how these things actuate internally, you would be shocked. It is so loose as to be a joke. So much room for improvement. I would love to do a mod on a /6 if anyone is interested. I would throw it in with a rebuild. The stuff that needs to be done to a tail shifter would best be done with the whole box here. If I have the box to play with, I can adjust to the box and its rods. Otherwise, I have to leave a little slop so it will fit all boxes.

GeorgeRud

Apr 15 2014, 11:36 AM

I always looked at that coupling and figured there was room for improvement in the design. Tightening the clearances should help, but I assume there must be some 'wiggle room' to allow the slight angulation as you shift through the gears.

Would a system composed of rod ends allow for the necessary movement and cut down on slop, or is there more clearance inside the gearbox that would negate any improvements to the external components?

Dr Evil

Apr 15 2014, 12:05 PM

My side shift kit would just be the shifter comb. All other factors are being evaluated and controlled for. The fore and aft have been tested. Tight tolerance used and effective. Now I need to see about removing the side to side shift rod play in the cabin by adding beef to the thickness of the comb teeth rather than just the width of them. I need a jig for this and hope to make one tomorrow if I can find my sawsall

Harpo

Apr 15 2014, 03:16 PM

Looks good Doc popcorn[1].gif

David

Dr Evil

Apr 15 2014, 03:23 PM

Thanks man

veekry9

Apr 15 2014, 03:39 PM

Dr Evil:
Delicate work,reducing the tolerance and clearances within the shifter forks.
Question:Are you using a jig to determine the distance to the ball detent?
I am about to embark on a re+re of the original tailshift TX that is now on the floor of the shop.Here it is 4 decades hence and I am considering a hydraulic shift mechanism
for the unloved early box.I have seen a number of attempts to resolve the "loose'
shift characteristics with limited success.There's gotta be a better way.

Krieger

Apr 15 2014, 03:51 PM

Cool!

'73-914kid

Apr 15 2014, 03:52 PM

Keep on pushing through with this Mike. BTW, if you need someone to do some testing per say with this, I'd be more than happy to.. Being a daily driver, my car undergoes more wear and tear than most, so it might be a good candidate for testing this out.

In all seriousness, I'm not trying to get a free part, but for longevity testing on the tightened clearances, it could be the perfect platform.

Woody

Apr 15 2014, 03:53 PM

914_teener

Apr 15 2014, 04:06 PM

Doc.

My box will be in transit in a week. I am cleaning it.

I would love a tighter shifting box.

All inuendos intended and true.

Dr Evil

Apr 15 2014, 05:39 PM

I'll at least be testing the one iteration of this to, at, and from Hershey this weekend. I will let others check it out, too. I hope to get both parameters that I am shooting for resolved to my satisfaction. It all depends on tonight and Thurs. The transmission is pretty much done other than the case seals and assembly. Once the shifter comb upgrade has been tested in the testing jig I will be building, and shown to work, I t goes in the box and the box in the car.

I am serious about doing a tail shifter one, just for the hell of it. I just need a candidate. Anyone need a rebuild? I can also do a 911/912 box.....I think I will use my local friend for that. A 911/912 box would be markedly easier than a 914 tail box. Only one shitty connection to worry about rather than 3.

stugray

Apr 15 2014, 05:50 PM

I have a tail shift laying in pieces from my last rebuild.
I wont be needing any of the tail shift pieces ever again.

I would donate to the tailshift cause if it also helps with the side shift development.

Let me know if you need some parts.

Stu

Dr Evil

Apr 15 2014, 06:08 PM

Ok, recruited a neighbors early 912 box that I just rebuilt.

Dr Evil

Apr 15 2014, 06:09 PM

QUOTE(stugray @ Apr 15 2014, 07:50 PM)

Thanks, Stu. I am balls deep in tail shifter parts, I need a whole box that will be built, modified, and then extensively tested by the owner.

mepstein

Apr 15 2014, 06:48 PM

QUOTE(Dr Evil @ Apr 15 2014, 08:09 PM)

QUOTE(stugray @ Apr 15 2014, 07:50 PM)

Thanks, Stu. I am balls deep in tail shifter parts, I need a whole box that will be built, modified, and then extensively tested by the owner.

Mike - let's talk at Hershey. I'm driving my '71. All stock and keeping it that way but I wouldn't mind a tighter shifter

Dr Evil

Apr 15 2014, 06:51 PM

Excellent

yeahmag

Apr 15 2014, 07:00 PM

Killer!

Dr Evil

Apr 15 2014, 11:57 PM

Success!

Tonight was very good. I made a jig for evaluating the comb in action. Did so, and got a lot of good data that I used to direct where to add material. I added material, honed the profiles, and saw a marked 90% reduction in the movement that will be translated into lateral movement in the cabin stick shift.

The profile for the fore and aft aspect still needs refinement, but with a transmission to finish, and with being freaking close to perfect for what I was trying for, I opted that an 85% reduction in fore and aft cabin stick slop would have to do

The test tranny is almost done. About 1hr left and then I need to jack up the car and swap them out. I wish I could have gotten a short shift kit in time, but Pelican said 7 days to process order, and the rest of the retailers would have likely been too slow as well. If I can score one at Hershey, I will install it on the spot. I hope to get feed back from several people as they take a turn driving.

I am beat, and pretty freaking happy.

Krieger

Apr 16 2014, 08:24 AM

Id like to see one track tested this summer and hear the results.

Dr Evil

Apr 16 2014, 08:28 AM

You and me both

I will make a few to send to people for such testing, I expect.

I think I will run down and take a vid of a stock one with play, and the modified one both being used in the jig

Stand by!

CptTripps

Apr 16 2014, 09:46 AM

Can't wait to see it this weekend!

I MAY have a short-shift kit from my last build somewhere. I'll have to dig through a few piles tonight to see what I can come up with.

(I really need to start digging through stuff tonight to see what I can/should take out there anyway.)

boxsterfan

Apr 16 2014, 09:48 AM

Awesome thread!! Would love to reduce the bowl of soup shifting feel in my side-shifter. Looking forward to a "production" model. :-) popcorn[1].gif

Dr Evil

Apr 16 2014, 09:52 AM

Stock shift console with stock play:

https://www.youtube.com/watch?v=vb2lBHNAVk0

Modified

It was not harder to shift, just harder to line up with one hand now that slop is significantly reduced.

https://www.youtube.com/watch?v=P2SmpwTKYvY

Dr Evil

Apr 16 2014, 09:53 AM

Technical difficulties with imbedding....wait one. (fixed)

'73-914kid

Apr 16 2014, 09:59 AM

Yepp, I'm sold. Love the lack of slop. Sign me up!

CptTripps

Apr 16 2014, 10:01 AM

That's bad-ass dude. Going to be a HUGE hit.

Black22

Apr 16 2014, 10:04 AM

Looks good!!

Dr Evil

Apr 16 2014, 10:06 AM

Do or do not.....

I am feeling pretty good. Cant wait to drive it.

Doug, that would be friggen awesome!

Mblizzard

Apr 16 2014, 10:18 AM

I am in for this!

Dr Evil

Apr 16 2014, 10:24 AM

Where as a Rennshifter addresses the problem at the end of the chain, my solution will address it at the source and will be far less.

The only thing that I see as a potential for loss of optimal is the in and out play on a box where I have not adjusted the internal rods. If your rods are cocked ever so slightly, then you can run into binding. The easy cure would be to allow for more slop in this direction. Thus, it is looking like two sets will be offered: I install and custom fit one to your box, or I send you a unit to install that will be only slightly less awesome, but still a huge improvement.

As for the 911/912/tail folks, I am still working on ways to get rid of the side to side play in the stick. The anatomy of the mechanisms are different enough to not allow for the simple solution done to the side shifters. Probably need to make a special shifter ball end.

bulitt

Apr 16 2014, 11:05 AM

Remind me how difficult it is to pull this rod out for shipping

914werke

Apr 16 2014, 11:06 AM

QUOTE(Dr Evil @ Apr 16 2014, 09:24 AM)

Where as a Rennshifter addresses the problem at the end of the chain, my solution will address it at the source

Are you suggesting that it would be either or of these solutions or would combo of the two allow the heavens to open and beams of light to shine forth from your shifter?

bulitt

Apr 16 2014, 11:34 AM

QUOTE(rdauenhauer @ Apr 16 2014, 01:06 PM)

QUOTE(Dr Evil @ Apr 16 2014, 09:24 AM)

Where as a Rennshifter addresses the problem at the end of the chain, my solution will address it at the source

Are you suggesting that it would be either or of these solutions or would combo of the two allow the heavens to open and beams of light to shine forth from your shifter?

JWest

Apr 16 2014, 11:44 AM

The RennShift addresses the large amount of friction in the factory shifter and adds the gate springs that 99% of manual transmissions are blessed with from the factory. Reducing play is only part of the picture. Lots of weak areas in the shift mechanism - have to hit all the links as each improvement makes the next one the weakest.

Edited out the drama after a good night's sleep...but you still get to see it quoted...

ablesnead

Apr 16 2014, 05:47 PM

QUOTE(JWest @ Apr 16 2014, 01:44 PM)

QUOTE(Dr Evil @ Apr 16 2014, 11:24 AM)

Where as a Rennshifter addresses the problem at the end of the chain, my solution will address it at the source and will be far less.

I don't see a slam on your product at all...I have seen before a defensive attitude in your response to perceived criticism ..I have seen great respect and appreciation from this site chatter for the rennshift..I am saving to purchase one soon...in in hobby viable solutions at a cheaper price than currently available will generate buzz...its not automaticly a knock on an already existing product .You and Jake get some skin thickner
Rant warning - sorry - you brought me into this...

I find it interestingly sad that many 914 owners feel the need to attack and put down those that produce parts specifically for these cars. I don't belive that I have EVER wronged anyone in a sale, yet you guys seem to treat me like the evil corporation after your money. I'm not StuffMart producing crap in China to put others out of business...

The RennShift addresses the large amount of friction in the factory shifter and adds the gate springs that 99% of manual transmissions are blessed with from the factory. Reducing play is only part of the picture.

As for the price, this is a very small market. If not for the similarities with the 911 version, I would not be able to make this a viable product at all.

I did make a cheaper version for a time - the RennShift Jr. Most of the features of the RennShift for half the price. Sold 2 in as many years. Price is not everything...

Sorry, but I feel that you guys go out of your way much too often to alienate rather than support those that make products for these cars (and it's not just me).

If you can make this product work well then it will be a good combo with the RennShift. Good luck with your progress - when I tried this mod I found that the pattern was overly constrained so it took too much deliberation follow a square corner from gear-to-gear. Much like driving with a true gated shifter in a Ferrari - cool, but kind of a pain.

Dr Evil

Apr 16 2014, 07:34 PM

QUOTE(JWest @ Apr 16 2014, 01:44 PM)

QUOTE(Dr Evil @ Apr 16 2014, 11:24 AM)

Where as a Rennshifter addresses the problem at the end of the chain, my solution will address it at the source and will be far less.

Rant warning - sorry - you brought me into this...

I find it interestingly sad that many 914 owners feel the need to attack and put down those that produce parts specifically for these cars. I don't belive that I have EVER wronged anyone in a sale, yet you guys seem to treat me like the evil corporation after your money. I'm not StuffMart producing crap in China to put others out of business...

The RennShift addresses the large amount of friction in the factory shifter and adds the gate springs that 99% of manual transmissions are blessed with from the factory. Reducing play is only part of the picture.

As for the price, this is a very small market. If not for the similarities with the 911 version, I would not be able to make this a viable product at all.

I did make a cheaper version for a time - the RennShift Jr. Most of the features of the RennShift for half the price. Sold 2 in as many years. Price is not everything...

Sorry, but I feel that you guys go out of your way much too often to alienate rather than support those that make products for these cars (and it's not just me).

If you can make this product work well then it will be a good combo with the RennShift. Good luck with your progress - when I tried this mod I found that the pattern was overly constrained so it took too much deliberation follow a square corner from gear-to-gear. Much like driving with a true gated shifter in a Ferrari - cool, but kind of a pain.

Dude, unclench.

1- Renshifter is $500+, FACT
2- It addresses the issue at the END of the shifter circuit, FACT

Did I post derogatory comments about your product? NO. Do I own one? YES. Have I always posted uncompensated positive reviews when asked about it? YES. So cool you jets.

I merely wish to build a better mouse trap. My enhancement, which has yet to be tested, if it works as I anticipate, will fix the problem at the source and cost a fraction of a Rennshifter, FACT. Also, stupid easy to instal.

If you dont like ingenuity and want us all to just accept what is already out there, then you are mistaken. My concept and potential product in no way diminish what you make and sell. For all we know, the Rennshifter will still be the superior solution, and I may not sell any of my units, and they may work stupid well in concert together. I dont know, that is why I am testing it and trying to refine it.

I in no way was making a personal attack on you, Rennshifter, or any other vendor. I have supported your product to people in public and private, and I only use it as a benchmark to beat.

Cant we all just get a long?

JWest

Apr 16 2014, 07:40 PM

OK, unclenching performed - do I need to send a copy of my insurance card or is the first time medical advice free?

Evil, carry on and make this thing work!

Dr Evil

Apr 16 2014, 07:42 PM

Drama off:

So, to change this unit you would need to drain the oil, remove the external shifter rod, transmission in neutral, remove two nuts, pull the console, install the new console, reassemble everything, put new oil in, adjust shifter.

As for 914 stuff, this is pretty easy.

If I installed it on your rebuild, nothing different would need to be done when installing.

Sooo, on that note, I am about to finish the assembly of the test/raffle box and then drop the trans out of my car and maybe put the new one in depending on how tired I am. I was up tweeking until 3am with this and the transmission, back up at 830 and feeling it.

I got my latest tatt finished, today

Dr Evil

Apr 16 2014, 07:46 PM

QUOTE(JWest @ Apr 16 2014, 09:40 PM)

QUOTE(ablesnead @ Apr 16 2014, 06:47 PM)

It's not excessively defensive when my product is called out by name...I had no business on this thread until that point.

Again, sorry for the rant - I've just seen too many sideways comments about good vendors (not the known bad ones) without real product feedback or useful criticism and I'm piling this on, not accusing the Dr. of doing this.

Evil, carry on and make this thing work!

I know how stressful it can be, Big Guy. Niche market, good product at a great price that is still not cheap enough for the masses makes it even harder. I still think your stuff is titts.

Have a beer on me

timothy_nd28

Apr 16 2014, 08:10 PM

Homeostasis has been achieved once again

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