The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: A10 Tim on 25.02. 2021 09:46
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Hi all.
Can any of you fine gents tell me which mainshaft pressed on G pinion goes with which gear cluster.
I have two clusters one marked EN36 and one marked V18 on the pinions (what do these marks mean)?
The one on the left I think is for standard s/a box and has nothing stamped on it.
The one in the middle came out of a s/a box pressed on to a plunger shaft to accommodate the Norton clutch and has V18 stamped on the pinion. Which is the shaft I want to fit.
The one on the right is a plunger shaft with V18 on the pinion.
Are all theseG pinions compatible with both clusters, as the dogs seem to engage ok?
Many thanks for your help.
Tim
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EN36 is a steel grade.
My observation is that the later pinions are sometimes marked EN36 and the earlier V18. I presume V18 was also a grade of steel but cannot confirm that.
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Hi JulianS,
Thanks for the info on the different markings.
The question now is, the dogs are different on the G pinions and are they all compatible with the pinion
Next to it.
Thanks again
Tim
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There is a tendancy for these boxes to jump out of third gear when the ends of the dogs get worn and rounded. The pinions on the plunger shafts look worn and I think may cause problems if used.
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The 24 tooth mainshaft sliding gear 67 3202 appears to be the same on plunger and S/A boxes with standard ratios. The full length teeth pinion on the right is a very early type (in my estimation) that maybe started life in a Longstroke Gearbox.
Julian can possibly assist here. The other two pinions should both be OK as regards compatible application, as the sliding gear is common, but yes, too much wear and rounded off and and they jump out of gear. Give them a try before adding to the scraps box as mix'n'match sometimes come good. They are examples of early and late variants, but for once I can't remember which is which. Bugger.
Swarfy.
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That's great info JulianS and Swarfy,
I'm restoring two s/a gearboxes, one for the bike and one to keep as spare.
Both boxs had the usual problem, worn layshaft and bushes.
I've replaced the bushes, oil seal and bearings in the first box.
The other box I managed to find a new RRT2 layshaft, Torrington bearings and thrust washer 42-3079.
But can't find the thrust washer on the blind bearing end which is part 42-3078.
Anyone know where I can purchase one? I've got the dims.
Perhaps I can get the machine shop to make me one.
Anyhow many thanks for the info chaps,
Tim.
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Hi Tim,
Have you tried Autocycle Engineering for the thrust washer?
I would not mix EN36 and V18 gears that run against each other
A 10 and Gold Star gearboxes seem to have EN36 gears , B31 and C series heavyweight seem to be V18
From experience with Rudge gearboxes V18 or VIB seems to point to a material called Vibrac
But I do not know if this is the same for BSA's ??
John
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Wow. I Googled Vibrac and got no results!
Update: it appears Google doesn't want to play with me today *razz*
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CJ Agree running mis matched parts in not ideal, but with a perhaps limited choice of readily available components even marginal parts that are serviceable make the difference between a runner and a stalled project. Worth a try if only for short term use.
Google Search of Vibrac brought me back to this very Forum, and a thread "BSA Gear Materials" from October 2011 to which you contributed most eloquently.
Swarfy.
Additional. Armstrong, Whitworth and the rest have an interesting backstory of the UK engineering industry of the 1920's. Takeovers, consolidations and back stabbing, Wikky has it all. Armstong Siddeley's Chairman, John Davenport Siddeley, later elevated to the1st Baron Kenilworth, was a tax exile, fingers in pies etc. A man very much in the right place and right time. We wonder where the money goes.....nothing changes.
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From 1922:
The manufacture of a new kind of steel known as "vibrac," the discovery of H.H. Ashdown and others of Armstrong, Whitworth Co. of Manchester, England, is told in advices received from that country. This new steel is asserted to have the valuable property of never tempering brittle and of being absolutely reliable and consistent in its behavior under any normal treatment.