[Fot] Gearbox thoughts

[rkramer3 at austin.rr.com]

I'm another guy that dumps a lot of oil. I've used VR1 dino oil in the crankcase and EP90 GL4 in the tranny and diff for a long time and changed it out almost every weekend or two. This works great with the hour or less racing I have done. I get the EP90 from Car Quest and it is jumped all the way up to $15.00 a gallon. I understand that the EP90 I is not recommended for use in overdrives so be careful with that. The dino oil in the Lemons/Chump/WRl endurance TR6 boiled and left after about 4 hours so that car now runs synthetic.

I now have a car with synthetic oils and I have let them run longer between changes.

Bob Kramer
rkramer3 at austin.rr.com

---- Dean Tetterton <tr3a58 at verizon.net> wrote: 
> Boy, Lots of good thoughts on this. Still lots of unknown's. Where are the engineers, Ha!
> 
> First off Glen is right, one needs to change the gear oil to keep the ground up piece's
> of metal to a minimum. Cheap to do and doesn't take that long. I even run a second
> magnetic plug in the fill hole.
> Second could not agree with Steve more. Double the bearing area is a good help. I have
> a question as to the TR4 press in bearing. Good in it gives more bearing area with the
> small rollers but I feel it suffers from oil flow. Is there any why to improve on that? I use them
> a lot but would feel better if I could see a way to get more oil thru them. I have pulled apart
> boxes where the rollers are packed with crud. 
> Third with the helical cut gears, there is a bit of pressure applied to the thrust washers as they
> try to push away from each other. Would the needle bearings help with that? Who knows?
> Is it worth the expense? Guess the answer here is straight cut gears. Yeah, a dog box...
> 
> Still lots of questions but nice to hear what other people think. We need to get together
> with some cold one's and solve all these problems. 
> 
> How about a T5?
> 
> Dean T
> Never stop improving the equipment.
> 
> 
> 
> 
> 
> On Oct 15, 2015, at 1:49 PM, Steve Yott wrote:
> 
> > I have had the opportunity to rebuild many TR gearboxes and a handful of
> > Stag boxes and would like to offer my opinion and that is what it is... my
> > opinion.
> > 
> > The Stag box added a lot of complexity to the area of the laygear and shaft.
> > The layshaft is different in that it has two outside dimensions that match
> > up to the spacers for the needle bearings. Now you have needle bearings,
> > spacers and thrust washers.  I am basically not a fan of this arrangement as
> > there are many more parts to fail and the needle bearings are known to fail.
> > Where the Stag laygear does benefit is from having two rear bearings!
> > 
> > The real problem occurs when excessive torque on the single rear bearing
> > causes the bearing and or shaft to fail.  Once there is play in the bearing
> > to shaft fit the laygear starts floating up, down and side to side which
> > then causes non-parallel loads on the bronze thrust washers and they begin
> > to fail.
> > 
> > I have bored a good number of laygears to install double rear bearings in
> > the rear of the gear.  I do not use the "open cage" bearing as the TR6 uses
> > but I use the TR4 type enclosed bearings.  I do this operation on all
> > gearboxes I rebuild now because I am sold on this fix.  The bronze thrust
> > washers will withstand the loads on them as long as they are square with
> > each other and the laygear end float is properly set and I use no more than
> > .006" of end float.
> > 
> > Just my opinion!
> > 
> > Steve Yott
> > 
> > -----Original Message-----
> > From: Fot [mailto:fot-bounces at autox.team.net] On Behalf Of Dean Tetterton
> > Sent: Thursday, October 15, 2015 9:20 AM
> > To: FOT Triumph
> > Subject: [Fot] Gearbox thoughts
> > 
> > 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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