Modifying 9Tooth MS for early gears

[Dougy Dee]

I have 8 or so of the late model 9Tooth mainshafts with the bearing end worn.
What is involved in having them modified to the earlier keyed style?
I had one cut down on a lathe and it was suggested to have them ground to size with a tool post grinder.
Is there a more efficient way?
Possibly a crank shaft grinder?

[Dougy Dee]

So... What about repairing the worn, undersized, bearing end on the 9Tooth MS?

I've been using Loctite 290 Green or Bearing retainer to repair. It seems to work well but using it for a high torque application like Subie or Diesel conversion I am a touch concerned. I am also using one of the Weddle MS bearing reinforcing plates to minimize movement in this area.
Recently I took several Gear Carriers to the machine shop to have the MS bearing hole tightened up. Too bad a MS bearing with an undersized ID isn't available...

[Marc]

Berg charges ~$110 for the entire operation (or $150 outright for a modified shaft) +$6 for a hardened key.
Doesn't say what machine they use, but they only set up for production runs every few months so I presume it's a machine that's normally busy doing something else...might be a crank grinder.

"LA TRANS020 Modify your 3.78 (splined at 3rd and 4th) mainshaft to the keyed type that accepts most all close ratio 3rd and 4th gears. You must convert back to the early keyed type mainshaft bearing and intermediate housing. We grind it to size, recut new snap ring groove, undercut reliefs and cut new woodruff key slot. From time to time we will have good used mainshafts that we can exchange. If you do not state that we must do the labor to your shaft we will exchange it if we have one to exchange."

"Conversion kit that allows you to use your late 1972-1/2-on intermediate housing with a modified GB 662 3.78 mainshaft. The kit consists of the following:
VWA020-311-123B Adapter bearing
VW 020-311-187 Early mainshaft circlip
VWB080-311-1511 Thrust washer
VWB113-311-309 3/4 slider keyed hub
VW 113-311-191 Mainshaft spring washer"

[Henryhoehandle]

Its been a long time but i think there is a way to just machine the end down and buy a special bearing to fit the later housing or use a sleeve.? I have a mainshaft that has been modified for the earlier hub, keys, etc. I have never used them but i have heard reports from other builders that after the shaft has been modified, that it is softer and that the key grooves wear out fast IF used in HP applicstions.

[Pablo2]

I never cared for the mod. A ton of work to end up with an unhardened keyway, doomed to fail eventually. Some guys experimented with two keyways with mixed results.

Berg used to sell synchro cones that were extra tall, which the customer finish ground to the correct height/clearance. In later years, we had some made this way too, which allowed cleaner installation of early gears on late mainshafts .. although you still had to machine clutch gear and gear bore.

One way to repair slightly undersized shafts is to have them ground and hard-chromed on just the damaged end.

[Dougy Dee]

I looked at the grind and hard chrome option earlier this year. $200 for one, 6 for about $150 each... Mind you, as much as I thought the guy was crazy the option is looking more attractive as time passes