Author Topic: Best & Lloyd mechanical pumps  (Read 6599 times)

Offline JFerg

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Best & Lloyd mechanical pumps
« on: June 24, 2019, 08:39:35 AM »
I will probably regret raising this, but here goes......

A standard B&L Mk II pump will deliver at maximum 500ml per hour driven at 1000rpm, according to messrs Best and Lloyd.

Whilst this is no big deal with most poppet valve engines of the period, which simply belch the surplus out, it is an issue for the Barr & Stroud engine.  One of the best documented and most widely repeated tales is that of Philip Brown and his 1,000cc B&S V twin engined Brough outfit, who seized the engine one day in Dorset whilst trying to cut back the oil to reduce the smoking.  What happens in the oil-tight B&S engine is that the excess oil builds up in the sump until the flywheels can get it, at which point commences a smoke screen of battleship proportions.  I've had this happen with Ever Onward, which is 500cc B&S powered.  The fix is to stop and drain the sump, which solves the problem, but isn't convenient, ever.  With the B&L set perilously close to off, it still over-oiled terribly.  It now runs a Pilgrim.  I don't have delivery rate data for a Pilgrim, but at around 4 drops per minute, it's fine.

Later Best & Lloyd pumps were designed to deliver only 200ml per hour, driven at 1,000rpm, 40% of the earlier pumps, and a tacit acknowledgement that 500cc per hour is too much.

My current project is 500cc B&S powered, and I have a lovely B&L Mk II pump, with tell-tale that I'd like to use, but I need to reduce the pumping rate to around 40%.

Has anybody gone down this path before?  What did they do?

thanks,
JFerg

Offline john.k

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Re: Best & Lloyd mechanical pumps
« Reply #1 on: June 24, 2019, 09:51:34 AM »
I accept the smoking,but just because to crankcase oil level falls to where a steady level is maintained,an engine doesnt seize..............a sleeve valve is nothing special in this,if oil floods an ordinary dry sump motorbike ,clouds of smoke issue out,and the exhaust will fill with oil.........in fact the motor cuts from an oiled plug long before it runs out of oil.....anyway ,the simple way to limit oil delivery is to limit the pump stroke..........which is precisely what Harley Davidson did with the pocket valve motors,where in the 26 on motors oil delivery was  modified by the throttle position.,as well as an adjuster screw. Pilgrim pumps. are similar,delivery is set by an adjuster,which limits plunger stroke.

Offline cardan

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Re: Best & Lloyd mechanical pumps
« Reply #2 on: June 24, 2019, 12:17:36 PM »

Most of my machines use a hand pump, but the later ones use drip drip feed powered by spring pressure - just push the pump down against the spring pressure once in a while to keep the oil dripping at the required rate.

Have you considered using the mechanical pump to lift the oil up to an adjustable drip feed on the tank that feeds into the engine, with the excess pumped oil going back to the tank? This sort of thing was common on bikes in the mid 1920s.

Cheers

Leon

Offline john.k

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Re: Best & Lloyd mechanical pumps
« Reply #3 on: June 24, 2019, 01:10:18 PM »
When the Jawa Eso motors were used in road racing,return to the tank was by simply hooking up a pipe from crankcase ,and it worked quite well.........some here may remember the ESo s had a Czech made copy of the Pilgrim pump,that was much better made than the british one.

Offline R

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Re: Best & Lloyd mechanical pumps
« Reply #4 on: June 24, 2019, 11:43:44 PM »
which simply belch the surplus out,

Until you find a more elegant solution, why not fit a breather and just "belch it out" ?

A catch tank/coke can  could probably be disguised as a period fitting,
if the idea of becoming a road oiler doesn't appeal.
Although with the price of designer oils these days......

Offline chaterlea25

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Re: Best & Lloyd mechanical pumps
« Reply #5 on: June 24, 2019, 11:49:48 PM »
Hi All,
On a previous B&L topic I wrote that a B&L I have is fitted with a smaller piston/cylinder than the others I have seen
Vintage replica's pumps are the larger size, their demonstration jig at shows has a pressure guage ????
so feeding a drip oiler would need some kind of relief /bypass

How hard would it be to sleeve the cylinder down and either make a new smaller plunger or reduce the diameter of the existing one?????

John

Offline 33d6

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Re: Best & Lloyd mechanical pumps
« Reply #6 on: June 25, 2019, 01:20:22 AM »
Hi JFerg,
I think a simple solution would be to halve the speed of the pump via a reduction device similar to that used by Scott owners suffering the same problem.

Being a two-stroke their Pilgrim pump is driven at engine speed as there are no half speed timing gears for the usual style of fitment. They have thought up a device using the gears out of a three speed bicycle hub to slow the speed down. I have the details somewhere. I'll hunt them out. Meanwhile start scouring the hard rubbish for ancient bicycle wheels.

Cheers,

Offline john.k

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Re: Best & Lloyd mechanical pumps
« Reply #7 on: June 25, 2019, 05:23:01 AM »
There was someone making new replica B&L pumps from brass ,but that was a wee while ago(80s?)....if still around ,he would make a custom one with a much smaller plunger......Maybe thats why Ariels had a drip feed glass indicator mounted up on the tank.........so you could keep an eye on the feed,and maybe bypass some back to the oiltank.

Offline JFerg

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Re: Best & Lloyd mechanical pumps
« Reply #8 on: June 25, 2019, 07:31:15 AM »
Thanks, all.

Ever Onward is a flat tanker with a hand pump and a drip feed, fed by the Pilgrim, as Leon suggests, but the current project (New Onward) has a saddle tank, so is not conducive to that arrangement.  I want something neater and tidier.  Interestingly, B&S initially made their engines with a B&L mechanical pump, but soon offered a "Mk I" variant which had no oil pump.  At the time, 1923, mechanical or "automatic" oiling was regarded with some suspicion, and an engine without the pump was naturally cheaper.  Finally a "Mk II" appeared, using the later, 200ml, B&L pump.

John K thinks like me.  Problem is that the B&L pump at minimum setting still pumps too much.  My thoughts had turned to machining the plunger to half the area and sleeving the bore, but I'm yet to look seriously at that.  It's a preferred option at the moment, but the B&L pump is a remarkably complex little pig, and I am yet to investigate fully.

33d6's reference to the speed reduction by the Scott technique is interesting.  I will look into that, and will start immediately scrounging for a 3 speed Sturmey Archer bicycle hub to donate the gubbins.

cheers,
JFerg

Offline john.k

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Re: Best & Lloyd mechanical pumps
« Reply #9 on: June 25, 2019, 10:08:13 AM »
havent  seen  SA hub on a bike in years...........Sturmey Archer still exist,in Taiwan,and make a very expensive 7 speed hub for mountain bikes....................there used to be an interesting story on Sturmey Archer,some con artists got controll of the company ,took the Nottingham council for a million or so,and then stole more millions from the remains of Sturmey Archer.......E DIT.....one place to find a small planetary gearset,or three is in a cheap air drill...probably lots of other similar tools have them too.
« Last Edit: June 25, 2019, 10:46:11 AM by john.k »

Offline cardan

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Re: Best & Lloyd mechanical pumps
« Reply #10 on: June 25, 2019, 12:05:21 PM »
havent  seen  SA hub on a bike in years...........Sturmey Archer still exist,in Taiwan,and make a very expensive 7 speed hub for mountain bikes.....

A bit off topic, but my wife's daily ride uses a Shimano 11-speed hub gear - quite a marvel! https://www.sheldonbrown.com/alfine-11.html

The Sturmey 3-speed hub goes back to the early 1900s in bicycle form, and was popular - but not very successful - in motorcycle form around 1912-1914.

Leon

Offline Rex

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Re: Best & Lloyd mechanical pumps
« Reply #11 on: June 25, 2019, 12:21:08 PM »
I believe it was used in an early tank too. Far better mechanical device than those French derailleurs!
The bloke making them for Scotts apparently isn't taking any more orders at present, either because he's snowed under or stopped doing it. Over-egging the pudding I think personally. The old Pilgrim, for all it's alleged faults, has worked well-enough on Scotts for decades.

Offline JFerg

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Re: Best & Lloyd mechanical pumps
« Reply #12 on: June 30, 2019, 02:48:10 AM »
In order to know exactly what I am dealing with, I've done some measurements.

Set the B&L pump in the lathe, measured 900 rpm.  B&L claim 500ml per hour at 1,000rpm, so I'm expecting 450ml at 900rpm, and 100ml in 15 minutes or so.  The B&L dial is marked in 16 increments between full and off.

With an oil tank mounted at the same height above the pump as it will be on the bike, and a delivery line to the same height as it will be on the bike, 1/4" copper line (B&L are designed for 5/16, but I have 1/4, so am using it) and 50weight oil, this is what happened:

Setting.             Tell-tale.                   Feed rate
100%. #16        out, steady.              32 - 36 drops per minute, approx 100ml in 14 minutes
50%  #8            pulsing 30per min.   36 drops per minute
#7.                    pulsing 30per min.   30 drops per minute
#6.                   pulsing 29 per min.   30 drops per minute
#5.                   pulsing 29 per min.   29 drops per minute
#4.                   pulsing 29 per min.   16 drops per minute
#3                    pulsing 29 per min.    5 drops per minute
                        only about half way
#2.                  pulsing 29 per min.     nothing in 3 minutes
                        only just lifting
#1.                  nothing                      nothing
OFF.                 nothing.                     nothing.

I can see why Philip Brown had his issues.  I will fit a Pilgrim.

Offline 33d6

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Re: Best & Lloyd mechanical pumps
« Reply #13 on: June 30, 2019, 06:55:59 AM »
Now repeat the exercise with the Pilgrim and put up the figures. I can recommend a good psychiatrist. Depression is an easily treated condition nowadays.

Offline JFerg

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Re: Best & Lloyd mechanical pumps
« Reply #14 on: July 24, 2019, 07:59:12 AM »
The Pilgrim is a far less complex design than the B&L, a very simple worm driven plunger.  Feed from the pump is controlled by a simple screw that limits the plunger travel.  Mine is an early one, with a plain screw and locknut, as opposed the engraved "dial-wheel" and spring loaded detente of later Pilgrims.  Thus there are no markings to guide the degree of operation, as there are on the B&L.  Against that, the Pilgrim has a built-in sight glass.

When I bench run the Pilgrim at the same measured 900rpm on the input, the pump delivers around 65 squirts per minute from the beak.  That remains constant, but as the plunger travel screw is wound in, the duration of each squirt reduces.  As that output volume diminishes, the volume of oil pumped up to the height of the engine oil inlet diminishes, from 105 drops per minute at full plunger travel, down to around 20 drops per minute with the screw fully home.  The limit here is the length of screw thread and thickness of the locknut.  A longer screw would allow greater reduction to the plunger travel.  I'll pull the locking nut out and try again another day, just to see what happens.....

33D6 is/was, as usual, spot on.  This could well drive me nuts for no relevant or useful purpose.