ET: Engine (Twin) Series ‘D’ Breather

[Cyborg]

On the VOC Spares site, the photo of the D spindle part number ET159/1 (or the later parts book MO13) shows the flat. I have an NOS one here in the photo, but didn't want to use it due to some pitting from corrosion, although the pits might help hold oil.
Based on your responses (thank you) I decided to go dig out the idler that mounts on it and there are two oil holes in the bush that line up with the flat, so now it becomes obvious that they put the flat there to hold whatever oil mist should find its way in. I recall looking at this pinion previously and wondering if it was OEM or something that was just made up by someone.... but now looking at a later (D era) MO13, it shows the oil hole in the bushing. As for indexing, I'm assuming the flat should be towards the top in order to hold more oil while hopefully keep it away from the cam and mag pinions because of the aforementioned reduced bearing area. If anyone can confirm my assumption on the indexing, it would be appreciated.

 

[Bill Thomas]

I have never had a "D", The Boss on that looks much shorter than a C type ?, So the casting on the cases must be thicker ?, When I did my Special C, I used a D spindle because I had one !. And I don't use the standard C breather anyway.

 

[timetraveller]

Interesting. That is what comes of having the works prototype. This bike, the prototype Black Knight has a late 'C' engine gearbox unit and the original log book shows that it was owned by the factory for about a year. The photograph you show indicated a rather short bush in the pinion whereas mine, being made from a 'C' engine has a long bush, presumably because the crank case had been machined to a depth suitable for a 'C'. I had never realised that this machining was shallower on the 'D's when compared with the 'C's.

On a different matter, I also have a 'D' rear frame triangle, nothing to do with the prototype, which has the correct parts for the prop for the enclosed 'D' rear cowl. 'D' rear chain guard etc. but also has the cross drilling for the brake cross over arm as was used with the 'B' and 'C. rear brakes. No such thing as a standard Vin.

 

[Cyborg]

Interesting. That is what comes of having the works prototype. This bike, the prototype Black Knight has a late 'C' engine gearbox unit and the original log book shows that it was owned by the factory for about a year. The photograph you show indicated a rather short bush in the pinion whereas mine, being made from a 'C' engine has a long bush, presumably because the crank case had been machined to a depth suitable for a 'C'. I had never realised that this machining was shallower on the 'D's when compared with the 'C's.

On a different matter, I also have a 'D' rear frame triangle, nothing to do with the prototype, which has the correct parts for the prop for the enclosed 'D' rear cowl. 'D' rear chain guard etc. but also has the cross drilling for the brake cross over arm as was used with the 'B' and 'C. rear brakes. No such thing as a standard Vin.

The crankcases I'm using are die cast, but not sure if that automatically makes them D. I had a look through KTB, the Vincent by Paul Richardson, and instruction sheet No. 6 and no clues on the D spindle flat location.
Thanks for the mention of the short bush Gents,
Top photo is the die cast set..lower photo is a B set. Seems you are correct on the machining.

On a side note, I seem to recall ( some time ago) someone on the forum wondering about what size the main bores were in a set of new OEM cases. These cases just create more questions than answers because the mains are .005" undersize and the bores where the G14 and G15 fit in the timing side case are undersize as well. Speaking of non standard Vincents.

 

[Bill Thomas]

Still learning !. Looks longer to me ?, "C" type. Or is the pinion wider on the "D" ?.

 

[Pushrod Twin]

I had a problem with the breather pinion seizing. It has a dural bush. I gave it a bit more diameter clearance and a bit more end float. Seems OK now.

Me too! In my die cast C motor 10545. Bush seized onto the spindle, well tight! Had to split it longitudinally with a hacksaw blade. Polished the spindle & fitted the the pinion from my '48 B motor which has what appears to be a cast iron? sleeve. The inside of that sleeve had plenty of natural lubrication grooves, it gave the distinct impression of having been drilled in manufacture, not bored, and certainly never honed!
So is there a preference for sleeve material?
I need to make a new bush to replace the alloy one, I am leaning towards cast iron, an old sash window weight could be good?

 

[Bill Thomas]

Can't find a "D" breather pinion on the spares company to compare.

 

[timetraveller]

Die cast cases do not mean it is a 'D'. They were used on the later 'C' models but I cannot tell you which engine number they changed over at. Those cases also included the better design for the top of the gearbox which can be seen by the hollow under the dynamo.

 

[Cyborg]

Can't find a "D" breather pinion on the spares company to compare.

They call it a D small idler spindle ET159/1

 

[Cyborg]

Die cast cases do not mean it is a 'D'. They were used on the later 'C' models but I cannot tell you which engine number they changed over at. Those cases also included the better design for the top of the gearbox which can be seen by the hollow under the dynamo.

yes, when I first got my hands on them, I was admiring the new and improved casting. Less chance of my gearbox and case turning into chutney.