Triumphrat

Thruxton · 09-06-2007, 07:36 PM

Has anybody had a T-140 transmission open?
I'd like to know if there are any yellow metal (brass, bronze, copper) parts in there.
I'm changing my transmission oil, and if there are any yellow metal parts, I'll need to get GL-4 gear oil, (hard to get).
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GrandPaulZ · 09-07-2007, 09:57 PM

Not sure about the T140, but the T120 has two brass bushings, one on each end of the layshaft.

Just use a good 90 wt. gear oil, like Castrol.

Thruxton · 09-08-2007, 12:17 AM

Quote:

Originally Posted by GrandPaulZ

Not sure about the T140, but the T120 has two brass bushings, one on each end of the layshaft.

Just use a good 90 wt. gear oil, like Castrol.

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NO, NO, NO:
if there's any yellow metal in there, it's GL-4 ONLY
I just ordered some.
It can be had, but you have to order it.
Any brand of gear oil that is GL-5 rated will attack brass and bronze bushings and thrust washers.
read = http://www.eng-tips.com/viewthread.c...=120197&page=1
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Mecchanica · 09-08-2007, 07:00 PM

Old wives tales. Maybe applicable to the preunits, but not a modern unit bike. The sulfur additives are not very active. If you have oilite bushes, as in preunit layshaft bushes/thrust surfaces, which have very large surface areas because of their porosity you might worry a little.
The modern unit boxes use hard phosphor or aluminum bronze in two gears and two layshaft thrust washers, and some of the aftermarket items are now using AMPCO 45 high nickel bronze. No worries.
You should use synthetic 75/85 (I use Royal Purple) Hypoid gear oil. Brit gearsets are not honed and lapped after hobbing, and they need the high pressure additives.
I have put nearly 90,000 miles on my 68 Tigerville since I rebuilt it with a T140 gearset. There have been NO glitches and nothing except clear oil drains out of the box. And that is with an engine which is 765cc, cammed, and running in very warm Hawaii, often in traffic, and also on the freeway.

Thruxton · 09-09-2007, 08:06 AM

Quote:

Originally Posted by Mecchanica

Old wives tales. Maybe applicable to the preunits, but not a modern unit bike. The sulfur additives are not very active. If you have oilite bushes, as in preunit layshaft bushes/thrust surfaces, which have very large surface areas because of their porosity you might worry a little.
The modern unit boxes use hard phosphor or aluminum bronze in two gears and two layshaft thrust washers, and some of the aftermarket items are now using AMPCO 45 high nickel bronze. No worries.
You should use synthetic 75/85 (I use Royal Purple) Hypoid gear oil. Brit gearsets are not honed and lapped after hobbing, and they need the high pressure additives.
I have put nearly 90,000 miles on my 68 Tigerville since I rebuilt it with a T140 gearset. There have been NO glitches and nothing except clear oil drains out of the box. And that is with an engine which is 765cc, cammed, and running in very warm Hawaii, often in traffic, and also on the freeway.

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I've confirmed from too many sources that GL-5 is damaging to yellow metal.
I'd rather not take any chances.
I'm married to an old wife, she hasn't misled me yet.
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Mecchanica · 09-09-2007, 02:34 PM

Going back over my notes, the big reduction gearboxes in a large commercial vessel I used to work on had four large phosphor bronze bushings (along with a fair number of ball and needle bearings) and the recommendation was for Hypoid 140. Never had any problems with those units.
I suspect that any problems with sulfur additives comes with the addition of water....the hygroscopicity of mineral oils allows more water to be mixed with the sulfides in the oil, creating sulfurous and sulfuric acids.
With enough heat, as can happen at wear points, I suppose the sulfur could bond directly with the zinc or (less likely) the copper to form zinc sulfide. But, as long as the lubricants are doing their job, there should be none of that contact. That would also argue for the synthetic oil base, as the film is stronger and less likely to allow that to happen, and it's much less hygroscopic.
Again, I think any problems were probably in humid climates, with mineral based oils and oilite bushes. Oilite is a very porous material made from powdered bronze which is then compressed and heated in a mold. That porosity increases it's surface area enormously.
The problem with giving credence to stories which appear in many places, is that they sometimes have a common source. Many bells ringing but only one wedding.
I consider my bike a to be rolling experiment, given all the modifications I have tried. The synthetic oils have been a huge success. 90,000 miles of experimentation is a pretty good baseline.

Thruxton · 09-10-2007, 01:37 AM

Quote:

Originally Posted by Mecchanica

Going back over my notes, the big reduction gearboxes in a large commercial vessel I used to work on had four large phosphor bronze bushings (along with a fair number of ball and needle bearings) and the recommendation was for Hypoid 140. Never had any problems with those units.
I suspect that any problems with sulfur additives comes with the addition of water....the hygroscopicity of mineral oils allows more water to be mixed with the sulfides in the oil, creating sulfurous and sulfuric acids.
With enough heat, as can happen at wear points, I suppose the sulfur could bond directly with the zinc or (less likely) the copper to form zinc sulfide. But, as long as the lubricants are doing their job, there should be none of that contact. That would also argue for the synthetic oil base, as the film is stronger and less likely to allow that to happen, and it's much less hygroscopic.
Again, I think any problems were probably in humid climates, with mineral based oils and oilite bushes. Oilite is a very porous material made from powdered bronze which is then compressed and heated in a mold. That porosity increases it's surface area enormously.
The problem with giving credence to stories which appear in many places, is that they sometimes have a common source. Many bells ringing but only one wedding.
I consider my bike a to be rolling experiment, given all the modifications I have tried. The synthetic oils have been a huge success. 90,000 miles of experimentation is a pretty good baseline.

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I'm happy for you.
as for me,
I'm told that GL-4 won't hurt anything
GL-5 MIGHT be damaging (actually I'm told it WILL be damaging)
so you can take the risks, I'm not a gambler.
http://www.google.com/search?hl=en&p...bronze&spell=1
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CommandoRdster · 09-10-2007, 03:40 AM

Thruxton- If you want to run synthetic gear lube(which I recommend also)there are lots of synth GL-4 lubes available.Redline,Amsoil,and Pennzoil come to mind. GL-4 should not be hard to find.Lots and lots of cars and trucks specify GL-4 in their manual trannies,for exactly the reason you gave.Any real auto parts store will have it.Maybe not the synth,but at least the regular dino whiz. If you really can't find it,let me know.We've got gallons of the stuff at the shop.

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Cheers!
Bruce

Thruxton · 09-10-2007, 08:11 AM

Quote:

Originally Posted by CommandoRdster

Thruxton- If you want to run synthetic gear lube(which I recommend also)there are lots of synth GL-4 lubes available.Redline,Amsoil,and Pennzoil come to mind. GL-4 should not be hard to find.Lots and lots of cars and trucks specify GL-4 in their manual trannies,for exactly the reason you gave.Any real auto parts store will have it.Maybe not the synth,but at least the regular dino whiz. If you really can't find it,let me know.We've got gallons of the stuff at the shop.

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Cheers!
Bruce

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Thanks for the offer, but I've got GL-4 on the way, VIA USPS
I can't find it in any retail stores but I can get it by mail order.
BTW, any thing that claims to meeet GL-4 and GL-5 specifications is unacceptable, it has to be GL-4 ONLY.
I get mine here = http://members.aol.com/antiquebmw4/gearoil.html
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GulfCoastDave · 09-10-2007, 01:34 PM

I've had the transmissions apart on both my T140s and both have bronze bushes at each end of the layshaft.
Best regards,
Dave