Hand Packed bearings and slick shift

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fastback
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Hand Packed bearings and slick shift

Post by fastback » Fri Jun 27, 2014 4:52 pm

I'm planning a budget 091 tranny for a few dragrace passes based on slick shift and considering hand packed bearings on 1. and 2. gears.
but have never done either before.

is there any common (type 113,002,091,094) bearings i can use the rollers from to use as hand packed bearings on 1. and 2.?
i just tested rollers (using rollers from 2 bearings ) on the 1 gear , but the seemed to miss 1/2'a'roller to complete the circumference
and if they can be used, i asume 2 spacers are needed on the ends of the rollers
or is there special rollers needed?

for slick shift is it OK to remove 1 out of 2 engagement teeth on the slider and gear to make a OK compromise between shiftspeed and strenght?

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Re: Hand Packed bearings and slick shift

Post by Pablo2 » Fri Jun 27, 2014 6:08 pm

If you visualize loose needles rotating next to one another, you'll understand why clearance between them is a good thing. With a stock bearing, you've got more than 1/2 needle diameter between every pair, so you can see that that 1/2 needle width divided among the whole lot is nothing. Almost makes you want to leave an additional needle out.

It's difficult to find needles of the perfect length, but the ones out of stock bearings are a bit short. A loose needle kit will have longer needles. Often, those needles are ground to length, leaving one side with a sharp square edge, and the other with the original radiused end.

After each idler is bore ground, one side of the bore will be slightly larger diameter than the other. This is the direction that all the needles will migrate toward. Make sure all the radiused ends are on the side of thrust direction. Easy to determine .. just install the needles with oil and rotate the idler a bit.

With Type I transaxles, we always had the pre-'65 clutch gear http://images.thesamba.com/vw/gallery/pix/1191619.jpg to make for a strong hub, having a full compliment of engagement flanks. Not so with the 091. So slick shift is actually a better way to go than pro-shift in an 091. There were a number of other features (which escape me now) that made 091 pro-shift more trouble than it was worth, but I think slick-shift is a viable option. You really have to look closely at clutch gear and operating sleeve to determine how many of the remaining flanks on the sleeve will actually be driven .. but I imagine that it's quite doable. If you're smart, you'll do the flank modification by hand, leaving the center portion of all modified flanks in place. (I've done this same thing with a few other marques, just to prove the concept on the dragstrip before committing to the design costs of aftermarket racing gears for those marques.)

My own personal preference was to use a Berg-style intermediate housing for a hybrid racing transaxle, thus making pro-shift or slick-shift a far simpler task (which allowed using the early Type I clutch gear, too.)
aka Pablo, gears, Geary
9.36 @ 146 in '86

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Re: Hand Packed bearings and slick shift

Post by fastback » Fri Jun 27, 2014 6:42 pm

Great info as always Pablo, highly appreciated :)

As for the rollers/needles of the stock bearing i thought maybe they would do it with spacers ,replacing the stock (fibreplastic or what it i made out of) cage to keep the needles in their original position.
but i asume longer needles without spacer is a better choice??
i see the point of space between the needles creating less space for oil and more friction but i asume that is a compromise to make to get a more "stable" gear.
i actually did not feel any less play with the handpacked stock needles than an older style steel cage bearing so i thought maye the 1/2 needle gap caused that play.

will take notice on the radiused end of the needles!

I've seen the flanks on 094 gears that are never actually in contact ,and you have mentioned this before, but a quick look on the 091 gears seemed that all of the flanks showed signs of contact/wear.

if it is this you mean regarding the center section of the flanks ;my plan was to use a dividing head and my mill to only remowe as little as necessary of the flank's "depth" to avoid contact of those flanks.and still use the remaing center section for "guide/pilot"

googled some pic's of other brand's using slick shift and came across pictures of some using the 3 keys for the slider with a modified syncro (just to keep the keys in and springs in place ??) and some not using any keys at all.
what is recomended ?

will post som pic's later and appreciate any further comments :)

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Re: Hand Packed bearings and slick shift

Post by Pablo2 » Fri Jun 27, 2014 9:03 pm

Are you speaking of spacers at the ends of the needles? It wouldn't make much sense to place anything between them (which is what I visualize when you say “keep the needles in their original position”). One thing I don't like seeing is the needles migrating toward the engagement teeth side of the idler, and away from the gear teeth side (where support is most needed). A ring type spacer would be OK to use, which would keep shorter needles toward one side (so long as the radial thickness isn't too great, which would hinder what little oil flow there is).

Loose needles are definitely a compromise. If you visualize two needles bumping into one another, you'll see that the backside of one is rotating opposite of the frontside of the adjacent needle .. thus considerably more friction is generated. But it still seems to work OK in a drag car.

It sounds like your bores are a bit sloppy, if a full compliment of needles feels similar to the stock bearing. That minimal 1/2 needle gap certainly isn't the cause of slop.

We may be tripping up a bit on semantics. Yes, the engagement teeth of the 091 are all equal, which allows doing this with a stock 091 gear. You wouldn't be able to do it with earlier gears, which have clusters of narrow teeth, and clusters of wider teeth. We only did it with aftermarket, which have equal teeth.

The 091 clutch gear (hub) has missing flanks/cogs/teeth .. whatever you wish to call them .. unlike the early Type I clutch gears as shown in the link I posted. This requires that you do as you suggest .. remove only the engaging portion of the engagement teeth on the operating sleeve/slider, leaving the center of those teeth/flanks for necessary support. This is why the hand machined method is superior to what Liberty does when they machine for pro-ring. Liberty removes too much material, requiring that the early clutch gear/hub be used (talking Type I).

The beauty of slick-shift is that synchros can be retained. But this would be more for a street & strip vehicle. For drags only, you can ditch all those parts.

I wish my storage locker wasn't so far away. It's been many years since I've had those specific parts laid out to explore the possibilities. Using 091 forks for hard shifts is a bit dicey. That's why I liked using the Berg-style housing and all early parts (including forged 4mm forks), which were more suitable for dragracing. But it can be done, and it's rather satisfying doing it on a budget.
aka Pablo, gears, Geary
9.36 @ 146 in '86

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Re: Hand Packed bearings and slick shift

Post by fastback » Sun Jun 29, 2014 4:00 pm

I have a couple of these hub's with flanges all the way.
these are from the newer boxes with integrated lock for the pinion nut.
guess they'll do.

so any advice removing 1 out of 2 , or 2 out of 3 engagement teeth?

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Last edited by fastback on Mon Jun 30, 2014 3:41 pm, edited 2 times in total.

Bruce2
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Re: Hand Packed bearings and slick shift

Post by Bruce2 » Mon Jun 30, 2014 2:48 pm

I use the thin cutoff wheel in the Dremel tool. The discs are about 25mm in dia and work better getting between two adjacent teeth when they're worn down to 15-20mm.

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Re: Hand Packed bearings and slick shift

Post by fastback » Mon Jun 30, 2014 3:35 pm

OK
i do have a mill with very good tool bit and a dividing head, so today i did the second gear
also modified a syncroring for 2. gear as a spacer , as i will use syncroring and no mod's to 1.gear
Will use a 094 1 gear as it is wider, but when using these gears i had to narrow the slider and teeth for the reverse(as these comes very close to the teeth on mainshaft)
and remove the outer "thrust/stop" on the engagement teeth to get full engagement.
will do the slider tomorrow.
went for the 1 out of 2 teeth removal.

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Re: Hand Packed bearings and slick shift

Post by fastback » Mon Jun 30, 2014 3:45 pm

094 Left VS 091 Right

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Re: Hand Packed bearings and slick shift

Post by fastback » Mon Jun 30, 2014 3:48 pm

a pic of (another) slider showing reverse teeth close to 1 gear before narrowing

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Re: Hand Packed bearings and slick shift

Post by Pablo2 » Tue Jul 01, 2014 1:07 pm

Looks good, fastback. With your excellent photos, this is becoming the best thread in some time ..

.. and yes, you made the better choice by going slick-shift. I honestly think Liberty's pro-ring mod was chosen (by them) for the ease of machining a pair of flanks off .. and they did this far too aggressively.
aka Pablo, gears, Geary
9.36 @ 146 in '86

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Re: Hand Packed bearings and slick shift

Post by fastback » Wed Jul 02, 2014 6:26 pm

thx pablo
will post more pic's ad i make some progress .
:)

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Re: Hand Packed bearings and slick shift

Post by fastback » Tue Jul 15, 2014 5:26 pm

slight change in plans as it goes forward
i choose to use manishaft , R/P and gears from the 091/1 4 speed T3 vanagon.
It has a coarse 29-6 teeth - 4,83 R/P (coarse maybe not equal to stronger , but gives me a little bit better ratio)
the geartooths are wider than the 4,57 091 so i asume they are pretty strong
Have done this conversion before from a 5 speed 094 to 4 speed into 091 before so it requires a few mods.

Reduced the diameter a litltle bit on the mainshaft to clear reverser gear
cut off the reverse and made threads on mainshaft for the intermediate bearing and narrowed the gears a little bit.
some of the width on 1/2 gear was never in contact in the 091/1 tranny to narrowed it a bit to get necesseray clearance
also tested my drillbits in the mill and reduced some weight on 2 gear.
hopefully it will make the engagement teeth last a tad longer.
saw this on some weddle gears i had in another tranny
once i got ~0.3mm down the machining would go in normal feed rate.

got removed engagement teeth on the gears.
next is the sliders.


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Last edited by fastback on Tue Jul 15, 2014 5:50 pm, edited 1 time in total.

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Re: Hand Packed bearings and slick shift

Post by fastback » Tue Jul 15, 2014 5:30 pm

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Re: Hand Packed bearings and slick shift

Post by fastback » Tue Jul 15, 2014 5:33 pm

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Re: Hand Packed bearings and slick shift

Post by fastback » Tue Jul 15, 2014 5:37 pm

here's the 091/1 vs 091 gears
and this is what happend to another 091 tranny when i got to excited with a beefy clutch when shifting , together with a lot of torque and semislick tires :D


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