G: Gearbox (Single - Burman) Burman lube questions...

A_HRD

A_HRD

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Matty,

An excellent summary, thank you! Two things though:

1. I understand that the modified Draganfly seal arrangement is supposed to be held in by the friction of the associated shims and washers under the outer circlip. But if that proves to be insufficient, what stops the whole seal-assembly turning?

2. I'm currently building two Series A gearboxes from what I believe to be early 1940s Ariel originals. (1BAPM/3 casting numbers). It has come to my notice that there are 2 different lengths of main bearing housings. I note the Draganfly website mentions it too. One is 11/16 inch from rear of housing to circlip groove, the other (and most postwar) is 13/16 inch. The seal mod fits nicely in to the 13/16 long housings but not so in the 11/16 ones - or at least not without some changes and considerable ingenuity. (This is just a "heads-up" in case anyone gets in to difficulties with fitting the seal mod).

Peter B
 
Matty

Matty

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My circlip was pretty tight against the oilseal and spacer from Draganfly and it was quite a tight fit on the periphery because of the thin O ring in the groove we cut into it on the outside.
I must confess that I also put some red Loctite round as well to help "stick things together"
Matty
 
brian gains

brian gains

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I was looking at the Draganfly oil seal revision but did not have room with only 11/16". Unforyunatly I took my eye off the ball and with the later necessary gearbox welding and machining repair I missed the opportunity to have the dim's altered to accept the 'modern' seal.
 
Matty

Matty

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Maybe you could have some turning done to the Draganfly seal metalwork to make it fit.
Matty
 
Matty

Matty

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It is a long time since I have seen a Draganfly Burman bearing spacer for the drive side but as far as I can remember it is really only a steel disc which is the same outer diameter as the bearing and has an oil seal pressed in, the inner of which which fits the drive side output shaft or perhaps a spacer on it
As I have said before I had a narrow groove turned into the outer of the disc and put a thin large diameter O ring in the groove which then became a tight fit and hopefully sealed the outside of the bearing .
Matty
 
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