Gland oil hole positions

[BRIAN MARSHALL]

Hi, Now here is a subject for us to argue about, oh all right then, ‘debate’, over the Christmas holidays…. Logically the holes in the crankcase sealing glands ought to line up with the holes in the cups when there is the most partial vacuum in the crankcase, just before the inlet ports open, so as to suck in the oil as effectively as possible, whether the engine has an oil pump or drippers. However the glands are different between pump engines and dripper engines. WHY ?
Then we have glands with two, even three holes. Again WHY ?
In my collection of bits and pieces I have glands where the holes have been carefully elongated into slots, and I can see the logic behind that, because the holes in the glands pass the delivery holes in the cups for what must be only microseconds, and the faster the engine is turning over the shorter the time, even if it is more often !
Right then, come on, argue, sorry, debate !!
Christmas Greetings to all our merry readers, and Bah Humbug to the not so merry…
Brian

[richard norris]

When Glyn Chambers helped me rebuild my 3 speed motor (well he did all the tricky bits) we looked through his collection of c/s glands to find replacements for mine which had tiny radial cracks. As Dave says we found 1,2 or 3 holes or a slot and neither of us could think of a reason for the variation. Maybe even the Works didn’t know which was best? I can’t remember what we ended up with but it was for end float reasons rather than holes. And best wishes to everyone at this “holey” time of year (groan).

[Dripfeed]

Gd moaning all.
could it be that dripper engines were earlier and a mod to glands would have taken place even if pill grims etc had not been fitted . I have run Scotts from a 1927 flyer through29 2 speeder 29 tourer to 1937 flyer all with drippers and 50 to 1 in the fuel tank had no trouble with lubrication on any of them . righto boys I can hear the hurricanes and spits taking off lets have it . Happy Christmas. Regards D F.

[richard norris]

I prefer drippers too. I have stopped putting oil in the petrol, just rely on the drippers. Doesn’t weaken the mixture and I think there is an article in technicalities pointing out that oil in the combustion chamber is not necessary. Mind you I don’t thrash the bikes.

[Dripfeed]

Hello Richard .
I used the 2 speeder as my every day bike in the 1970s and it was flat out at every opportunity I find the undersides of the pistons ( small ends ) look a little more comfortable . Regards D F .

[richard norris]

Good point, I haven’t examined mine and hope not to have to for now. Perhaps I’ll reconsider – what with anti-ethanol additive and oil there won’t be any room left for petrol!

[djcb]

All my engines have gaco type seals on the cranks which means the normal metal sealing glands are replaced with a plain aluminium bronze thrust washers. As the pump is quite capable of delivering oil at considerable pressure, I have seen 90 psi against a dead head, the thrust washers are recessed by .015″ on the oil delivery side out to about half the distance to the OD with three radial V grooves filed in about 010/015″ deep to the OD This then acts as a non return system as well as floating the cranks on a film of oil at the thrust washers. Very straight forward and very reliable. Not suitable for drip feed systems.

[BRIAN MARSHALL]

Hi Dave, Are your thrust washers ground to a set thickness to give the correct end-float on the crank assembly, which the factory stated as 1/64″ for standard glands?
Brian

[djcb]

Hi Brian ,seasons greetings.

The thrust washers are machined to the same thickness as the gland plates and the end float is taken care of by using shims in the same basic way as with standard glands. Shims of course if required go between thrust washer and main bearing end face. Just as an aside, at the tender age of 20 I went to St Marys Row to pick up a bottom half that Matt had refurbished for me.We discussed some of the finer points particularly on crankshaft end float, and his instructions were quite simple minimum .015″, maximum .040″ provided everything rotated freely. My preference is .025″.

[Author]

Posts