091 pinion bearing into early box

[Kiwi1966]

Good Morning,
After some advice please when using the 091 Fag pinion bearing in a early 002 bus or a beetle case.I have used two of these in previous 002 gearboxes I have rebuilt and omitted the thrust washer between the pinion and first gear due to the 091 bearing being wider than the original bearing and did not put oil grooves in to the 1st gear thrust side. Im currently building a AO box up for my 54 beetle with the same 091 bearing and am thinking since the thrust washer I am omitting has oil grooves maybe I should be putting oil grooves in to the thrust face of first gear so oil gets to the 1st gear bearing. As I said I did not do the oil grooves on the 002 bus box in my westy and it seems to be ok so far but wondering if this bearing may get starved of oil. Thoughts please gearheads

Thanks Ross

[[email protected]]

The OEM 091 1st gears do have 3 oil reliefs. Weddle has them on both gear sides of their hd gears.

[Casting Timmy]

The 113 big nut pinion bearings took the washer and the gear didn't need oil groves cut, or at least the factory didn't cut them in.

The 002 and 091 pinion bearings didn't use the washer and the factory cut oil groves in the gear.

I would suggest cutting oil groves in the gear. First gear also needs a little more end clearance than the other gears, I shot for .010" end clearance. Sometimes it will be a little more (or a lot with aftermarket gears at times) and that's fine.
_________________
T1 IRS Rebuild Book on Lulu.com
http://www.lulu.com/shop/tim-marshall/t1-irs-transaxle-book/paperback/product-24055997.html
As seen in Volks America Issue 14 Page 11 (Full page review)

[gears]

Not a real problem thrust surface, and grinding oiling slots would GUARANTEE a cracked pinion bearing inner race.
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[Kiwi1966]

Thanks for your replies, was the original thrust washer oil grooves to lubricate the thrust surface or the 1st gear needle bearing or a combination of both ,
and Gears are you saying if I was to put oil grooves into the Ist gear thrust surface this could lead to cracking of the pinion ibearing inner race.I really appreciate you guys advice as I do enjoy be able to wrench on my own Vws

[gears]

What you should pay attention to is adequate side clearance (for a street car, the high end), and using new needle bearings whenever possible.

Yes, you could very well end up with a cracked inner race if you grind oiling slots (on the flip side of your photo).
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[[email protected]]

[gears]

Grinding oiling slots on the inner race of the bearing leads to cracking of the race.
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[Casting Timmy]

The inner race does crack enough on it's own I wouldn't touch it.

Actually Folts told me the trick of modifying 1st gear idler and the race but cutting them the thickness of the thrust washer. Then with a narrower bearing you can use the thrust washer on top of the inner race of the 091 pinion bearing to keep it from cracking.

He will still put some oil groves in the 1st gear idler even knowing it's going on top of the thrust washer with oil groves.

I really wish there was a hybrid of the 113 and 091 big nut pinion bearings. Thrust washer present and compromise the bearings with small in back and larger in front like the 091, but they'd have to do smaller than the 091 to make it work. Maybe something like the 113 sized bearing in back and an 002 in front?? I think the 113 big nut would be a better bearing for a lot of T1 based off road cars.
_________________
T1 IRS Rebuild Book on Lulu.com
http://www.lulu.com/shop/tim-marshall/t1-irs-transaxle-book/paperback/product-24055997.html
As seen in Volks America Issue 14 Page 11 (Full page review)

[[email protected]]

I do like Dave’s modification to use a thrust washer with an actual 091 bearing, but what “stress level” is this suggested?

I can count on the fingers of one hand the amount of split 002/091 front inner races, or 113 thrust washers I’ve found in transaxles. 99% were due to the pinion bearing retaining nut being loose so that the bearing halves were slaming into each other. I’ve serviced transaxles from drag cars with 300+hp running hundreds of passes, and off-roaders with V6 Honda’s, and Ecotec’s that didn’t have cracked races. Are the races cracking in 350hp applications? 400hp applications? The air gets pretty thin in the Aircooled VW world of those using VW based transaxles with 400+hp. Dave Folts, and gears have forgotten more than most, including myself, will ever know about VW transaxles. I just am not seeing 002/091 races cracking in 85% of the VW enthusiast world in 2020.

If the 113 311 219A bearing with the 4 bolt retainer is not having issues cracking inner bearing races, then why aren’t the 113 311 219B bearings more popular?. The 219B bearing uses the exact same inner rollers/races as the 219A, but has the late outer race that uses the single large retaining nut. With the exception of maybe the gear roller bearings that went to plastic versions with shorter/fewer rollers, and some of the tiny case mainshaft bearings on the other side of 1st, just about everything that has evolved in a VW transaxle imo was for added strength/reliability. No one wants to pay to manufacture all the variations of 113/002/091 parts if there is an interchangeable version that is the most economically feasible to produce, and is the “best” design.

[gears]

The 219B bearing was the off-roader's choice. VW may have taken a step backwards with the 091 bearing. I understand their reasoning .. bigger rollers on the power-thrust side .. but this, combined with removal of 1st gear thrust washer, introduced a weakness that didn't previously exist.

Aside from loose tensioning nut, shockloads found in off-roading cause the majority of cracked inner races. I wouldn't expect drag racing to cause cracked races, nor would I suspect higher horsepower to have much to do with it. (Knowledgeable off-roaders can lessen shockloading with precise throttle control when airborne.)

Flat grinding the race is completely different than grinding grooves. I'm glad guys like Dave (and Rancho) are experimenting with adding thrust washers back into the 1st & 4th gear designs. These guys add tremendously to the group knowledge. Anyhow .. fun discussion.
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[gears]

Since Ross's original question has been addressed, and his thread has morphed into a more general discussion, here's a brain twister for the trans builders:
When is "adding oiling grooves into the thrust surface of a gear" counterproductive ?
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[[email protected]]

Hmmm..... Since Weddle’s gears have 3 grooves, and the hd hubs have the three through holes, I thought the more the merrier. Even the splined hub 002 3rd/4ths with their .020+ endplay have the three thrust grooves on the tiny surface of the syncro cone. I’ve seen a few 4th gears that ride along an 091 mainshaft bearing grooved since the bearing race is the thrust surface. Maybe adding oiling grooves to a 4th when it has a spinning thrust washer with the grooves already?

[Casting Timmy]

Some of the new gears I've seen from Weddle with hardly a thrust face to them? Hahaha

I would think that areas like 3rd's face against the 2nd of the mainshaft would be bad. While not the on power thrust direction, it would do the off power braking thrust if using the engine to slow down. Maybe gear cut against gear cut situation, or when a thrust face is used as a solid stop under load like in the bronze load bolt of a Mendeola, or possibly your fourth gear thrust set up for drag racing??

Awesome question Gears, not sure if I got it right....but like the brain twister.

[gears]

Like the 091 pinion bearing, the 091 mainshaft ball bearing has also incorporated the thrust washer into the inner bearing race. 4th gear now thrusts directly against this inner race, instead of a thrust washer.

This isn't really a problem in the Type I vehicles, but with our 5,000+ pound Syncro Vanagons with TDi and SVX engines, some of which the owners insist on doing 75mph up hills (and freeway driving for hours on end), it becomes a REAL problem .. even with the larger diameter 123C bearing.

The erosion that occurs on this inner race is NOT from lack of lubrication, and in fact efforts to "get oil between the two surfaces" by adding oiling grooves merely reduces surface area, and exacerbates the problem.

What's really occurring is illustrated by these two links:

Mechanical Precession https://commons.wikimedia.org/wiki/File:Animation_of_mechanical_precession.gif

linear friction welding https://www.youtube.com/watch?v=iG3t0Q7UuCU

BTW, I had help from a smarter guy than me in sorting this out .. Ron (Howesight)

So, what causes Mechanical Precession in this case, and how do we address the issue ?
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[[email protected]]

I would have thought that the mechanical precession would be kept to a minimum with the gear roller bearing. I’m not much of a fan of hand packed bearings for street cars, but is adding support to keep the surfaces better aligned part of the solution? I would have thought the difference in speed where the wear would occur would be when the trans is not in 4th gear. Wouldn’t the mainshaft, inner front bearing race, the hub/slider/gear be all going the same speed when in 4th gear?

[gears]

Virtually ALL the erosion is occurring while 4th gear is engaged. A helical gear will always be cocking when under such an extreme load as presented above (heavy vehicle, high horsepower, high speeds, large frontal area/wind resistance).

The continuously cocked gear rubbing against the inner race in an elliptical manner (while the two shafts rotate) is the mechanical precession, leading to minor friction welding between 4th idler and the bearing's inner race .. essentially eroding the hard steel inner race (surprisingly more than the softer gear).

Additionally, in more extreme cases, all wear on the gear teeth is to one edge, while the opposite edge is almost without wear. Anyone servicing drag race transaxles sees a similar wear to one edge of the 1st gear idler, all of this wear occurring during launch. You can hand pack to try reduce cocking, but nothing eliminates it. Clearance for the needle bearings is necessary, so the problem will never be fully eliminated.

Gear cocking causes wear to one side of the gear tooth:

_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[[email protected]]

So this is more like a spinning coin coming to rest on a hard surface?

[gears]

I prefer to call it ovalling or orbitting, rather than mechanical precession. If the idler were running zero clearance on the bore, it would be stationary against the race, because it wouldn't be cocking. But clearance allows it to run on an ever so slight elliptical path, with the helical design causing the cocking, while the helix is also thrusting it against the race. The constant high frequency vibration/friction between surfaces leads to erosion and the appearance of a light friction welding on both surfaces.

That's an .011" step eroded from the race by the idler gear.
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[Ohio Tom]

This is why reducing the thrust clearance helps to keep the gear square.

GBE suggested .001" for first gear. I have found that to be too tight, but I got less than .005" on first gear.

When welding 3rd or 4th. I always add material and grind the thurst surface to reduce thrust play for the same reason.