Alternative to gear lube

[herculewazo]

History: 1948 2 cycle air cooled Frazer Rototiller with bad seal (original leather) sucking 80 weight from gearbox into crank / fuel mix. Existing shaft has 20 + thou. damage at seal mating surface. Off the shelf seal sizes do not allow turning down this surface. Many Frazer users with this problem simply run the transmission dry to avoid a 'battle ship smoke screen event'. I'd like a better solution.
Question: This thing is very heavily built (picture a Troy's vastly bigger brother ... roughly 650 lbs of churning ...) so could I use a modern thick grease like lube, coat the bearings & once again use this machine? No bushings involved.
Machine is used in two hour intervals 4 times per year & 2 year tear down is not out of the question. I have three crank shafts with the same issue. My guess is that with years of storage the original leather seal allows moisture the pit the shaft at the low point.
Building up the shaft & turning it would also require balancing & these $s are not in this movie.
Suggestions?
Thanks.

 

[romke]

A thick grease might be taking it a bit too far. A typical softer gear grease (NLGI 0 or 00) might be more appropriate

 

[Tmoose]

http://www.skf.com/us/products/seal...als/wear-sleeves/skf-speedi-sleeve/index.html

http://www.skf.com/us/products/seal...er-transmission-seals/v-ring-seals/index.html

Block the gearbox breather to limit oil flow during low pressure events?

 

[herculewazo]

Thanks!
I have some NLGI 0!
Breather is the dip stick ... I may be able to thread the dip stick hole & plug or restrict it ... good point.
Customizing WW2 era equip. can be a challenge. These machines were made to supply the expected 25 acre Market Gardens of post WW2. Small tractors with PTO & 3pt hitch were just arriving & eventually walk-behinds died out. Built like a tank except for the leather seals!
Thanks again.

 

[MikeHalloran]

Maybe you can get a Speedi-Sleeve to fit the crank seal diameter.
It's just a thin stainless sleeve that you press over the worn part; no turning or grinding, if you can get one in the size you need. Then the original seal, or something similar, should work.

Another idea; maybe you can find space to fit a Merkel-Forsheda V-Ring Seal on the gearbox side of the crank.
It looks like a square section o-ring with a cone-shaped flange, all molded rubber, that bears against a radial face, e.g. inside face of gearbox, or old seal housing, or maybe a planar face built up from filled epoxy, in order to provide a reasonably durable face seal for a rotating shaft.




Mike Halloran
Pembroke Pines, FL, USA

 

[TugboatEng]

There are repair options for the shaft. Electroless nickel could likely be used to build up the lost material without distorting the shaft. The nickel can achieve very high hardness, HRC 65, close to hard chrome. This will keep it from wearing out again.

 

[Tmoose]

My links are to the products Mike H described.

Dan T