1935 B35-3 Big-end oil feed quill

[Phill A]

Can anyone shed any light on which way round the big-end oil feed quill should be fitted on a B35-3?

When I stripped the engine, the steel end was fitted into the crank. However, looking at the sectioned view in the 1935 parts book, it appears the brass end should go into the crank instead.

I've searched online but haven't found a definitive answer. What I have found is that on a number of similar bikes from the same era with a comparable arrangement, the quill is usually fitted with the brass end into the crank.

What makes me question it is that the steel end seems to match the profile of the centre hole in the crank much better than the brass end. On the other hand, the brass end has a flat which seems to suit the flat-bottomed hole in the timing cover.

Has anyone rebuilt one of these or knows for certain which way round it should be fitted? Any advice or first-hand experience would be much appreciated.

[Steve.S]

I'm afraid I can't give you a definitive answer, but the following may help (or not).
You should have the following parts.
15-1776 Oil Feed End....the brass thing.
27-185 Oil Feed Retaining Washer. This is a spring steel washer with ears at right angles.
27-183 Oil feed sleeve. Looks like a steel bullet.
15-1774 Oil feed sleeve spring.

The stepped steel adaptor fitted to your crankshaft does not appear to be a BSA part. (I can't find it in the parts book, and my engine is not fitted with one.)
It seems I had all the correct parts, but all I can remember is that after a little head scratching, it soon became clear how it all went together (and I am on the wide side of thick.)
Perhaps if you could post a photo of the inside of your timing cover with the retaining washer fitted, it might jog my memory?

[Phill A]

Thanks Steve,

I have found reference to Part No.27-183 in the 1935 parts book and the corresponding image looks to match, see attached.

It would seam that I have all the four parts listed.

[Phill A]

I have attached an image showing the orientation relative to the timing cover in which it came apart. You can just see the retaining washer sat to the side.

[Steve.S]

I wonder if there is an internal taper in the end of the crankshaft?
If memory serves, the brass mushroom is spring loaded in the timing cover, held in place by the retaining washer.
The spring would be fitted inside the sleeve bullet, and the brass mushroom would be slid into the bullet, and the brass mushroom head would poke out of the retaining washer which clips over the timing cover boss and would then seal against the taper in the crankshaft.
What I thought was a spurious part is clearly the sleeve bullet. However, I have always found that the illustrations in the Parts Books are very accurate, but your bullet seems to have a much larger major diameter than is shown.
Why don't you assemble it as I have suggested, and let us know how you get on?

[Phill A]

Thanks again Steve,

Looking again at the section view I've just noticed that it does show the spring closest to the crank. The spring lives inside the steel part so maybe it was correct how I took it apart?
 
I have coloured the steel ends radius in black marker pen and spun it in the crank centre hole with a drill. It does appear to make good contact but I may lap it in a little too.

What worries me is that I bought the bike as a non runner and the big and was very worn. I guess it will be fairly low oil pressure anyway as its all roller or ball bearings for the bottom end assembly.

[Mark Cook]

Not that I'm an expert on these engines, but from other experience I would have thought that the steel part presses into the outer casting.  The brass mushroom is pushed against the end of the crank with the spring.

Mark

[Steve.S]

We seem to have varying opinions here.
It's worth bearing in mind that Mark is a top class engineer who runs PES Engineering, and has an enormous amount of BSA experience.
You now have 2 people suggesting that the brass mushroom runs against the crankshaft, but you don't seem to like this idea.
It seems that both Mark and I believe that you had it arse about face.
Could you tell me whether or not the steel bullet will slide fully into the timing cover with the closed end first?
If so, then the order would be bullet, spring, mushroom and finally, retaining washer. The mushroom end would be sprung loaded and poke slightly out of the retaining washer....to lightly contact the crankshaft when assembled.
I have a feeling that your mushroom has been got at, because I don't recollect it having a 'nose'.
I think a previous owner has turned it down in a lathe.
Also, the surface looks poor and needs dressing, so you would need to check contact with the crankshaft internal taper using engineers blue.
To complicate matters, it seems to me that BSA made several minor changes to the lubrication system in the Thirties. I have seen several BSA diagrams of this section, and they are all very small, indistinct and slightly different.
I suppose you could assemble it your way, but with the (incorrect?) nose on your mushroom, it would not seal against the oil hole in the timing cover, whereas the bullet would.
I wonder if you could try to assemble it as we both suggest and let us know how you get on? It will either all fit together, or it won't.

Oil pressure when cold should be around 8lbs, but in theory it doesn't need much pressure at all, just flow.
I would send the crankshaft and conrod to Alpha, so they can overhaul it all, although I'm sure PES could do the same.

 

[limeyrob]

BSA were always very diligent with their bearing surfaces and materials.  I would expect the "bullet" not to rotate and for the rotation to take place between the brass mushroom and the crank shaft.  This makes sense as the surfaces that are "running" are the correct materials.  We are calling it "brass" but I suspect it was originally phosphor bronze

[Phill A]

Thanks all.

I can also vouch for Mark's experience. He kindly reverse-engineered and made a replacement set of timing pinion shaft bushes with the correct double-loop oil grooves for me. PES did a cracking job. They're BSA part no. 31-240 if anyone's ever looking for a set.

Alpha have been contacted and will be overhauling the crank. It's good to know there are still British companies like these keeping the old bikes going and able to support projects like this.

@limeyrob, I think you're right – it could well be phosphor bronze, or at least that's what it was intended to be.

As I mentioned, I bought the bike as a non-runner, and it was assembled with the steel end into the crank. The "bullet" fits fully into the cover, and the whole assembly will fit either way round. The surface looks rough in the photo, but that's just the light catching it – both parts are actually in remarkably good condition.

As a mechanical design engineer, I'd also say it makes more sense for the non-ferrous part 😉 to run in the crank.

The sectioned drawing looks to show a radiused bottom to the hole in the timing cover, but mine's flat-bottomed. I'm wondering if a previous owner had done this, then machined the flat into the end of the bronze/brass piece to suit?

It all seems a pretty sloppy fit in the case as well.

[Mark Cook]

Thanks Steve and Phill.
I'm glad your happy with the bushes Phill.
I'm not trying to tout for more work as we are behind with a lot of projects.
But just to let people know, we make Big End Kits, shafts, conrods and whole cranks.
And all manner of other parts.

Mark