[Fot] Gearbox thoughts

[Jeff Durant]

Bob and Dean,
I've built up 2 gearboxes using Stag cases and laygear set-ups.  The 1st uses a late TR6 gear set, a J-type with a Volvo annulus and planetary(28% I believe).  It is in my TR250 street car running an old regional race engine.  It is the smoothest TR gearbox I've ever had.  The tall OD is great for very high speed cruising with the 3.45 rear.  The engine pulls it effortlessly.  I run redline synthetic.
The 2nd is a early, steel bushed, CR gear set on a modified late MS, Stag case and Laygear set-up for the TR6 racer.  I have not run it yet however.  
I've heard even this set-up will fail under hard racing conditions but last far longer than a standard TR6 Laygear set-up.
The dog box or a jericho is the way to go I'm told but pricey as the last several posts have commented on.
Regards,
Jeff Durant
TR6 #12
TR250 street


> On Oct 15, 2015, at 9:10 AM, <rkramer3 at austin.rr.com> <rkramer3 at austin.rr.com> wrote:
> 
> I bought a Stag J-Type box a while back intending to convert it but I haven't done it yet. Curious what the group has to say.
> 
> Bob Kramer
> rkramer3 at austin.rr.com
> 
> ---- Dean Tetterton <tr3a58 at verizon.net> wrote: 
>> Since we have been thinking about gearbox's. The Stag layshaft was changed by Triumph to try and make them last longer due to the additional torque of the V8. They added needle bearings in place of the brass thrust washers at each end and an additional bearing  in the lay gear at the end where 1st gear is. Has anybody tried this set up in a racing box? Does it help in the wearing of the layshaft? 
>> 
>> The addition of needle bearings means that the spacing of the box inside where the lay gear rides is greater. The needle bearings being thicker than the thrust washers. This means that the Stag box is different inside. 
>> I have been able to make a tool that will cut the inside of a TR box to be the same as a Stag. I plan to build a box using the needle bearings. Don't at this time plan to put another bearing inside the lay gear. If I make the lay gear deeper inside, I am afraid it will not be hard enough for the bearings to ride inside. 
>> 
>> Before doing all this, has any body gone down this road before. If so what has been the experience? 
>> Also any body with thoughts chime in. Is it worth the effort?
>> 
>> Dean T.
>> 
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