ESA with disc spring washers

Vincent Brake

Well Known and Active Forum User
VOC Member
Hi out there,
anybody whom has done a conversion of the ESA yust simple by turning the PD3 narrower, adding disk spring washers (how do you name them in UK language) face to face and back to back, and close the whole kit by ring PD8 + nut PD7.
advantagese are obvious, no broken springs.
the only disadv I can think of is the progressive action on the disk springs, however they may be (when hard driving) be locked up firmly, no harm done.
I cant find anything in MPH nor in forty +10 years litarature.

???

thanks for nonsence and sense on this item

Vincent Speet
 

clevtrev

Well Known and Active Forum User
VOC Member
Hi out there,
anybody whom has done a conversion of the ESA yust simple by turning the PD3 narrower, adding disk spring washers (how do you name them in UK language) face to face and back to back, and close the whole kit by ring PD8 + nut PD7.
advantagese are obvious, no broken springs.
the only disadv I can think of is the progressive action on the disk springs, however they may be (when hard driving) be locked up firmly, no harm done.
I cant find anything in MPH nor in forty +10 years litarature.

???

thanks for nonsence and sense on this item

Vincent Speet

I have a design using nested wave form springs.
Similar to bellville washers, which I doubt have enough lift in the stack.
 

Vincent Brake

Well Known and Active Forum User
VOC Member
Hi, I am intending to use belville washers d=31 x D=63 x t=1.8 and machine them down to 1,5 thickness, then I can stack them and with a bit of luck fit them in de casing (while not using a to thick gasket of say 10 mm ) I will make a design up for it I think as there seems no one whom have made it up before.

Clevtrev, is this deisign of yours in thrust ways compatable to a series D number of holes in theirs ESA

keep m rolling and brake well

Vincent
 

Tom Gaynor

Well Known and Active Forum User
VOC Member
Esa

I've been reading the PEI autobiography. The ESA was designed to use a rectangular section wire spring (as most other bikes i know of did) but although Vincent got the go-ahead to buy it (material was "rationed") couldn't find a supplier so used altered the design at short notice and used Velo clutch springs, soon augmented by even smaller springs inside the already small "big" ones. It's a reasonable bet that by the time the D came along they were committed to a system using thousands of silly little springs, but that a better solution wouldn't cause PEI to rotate in his grave....
Must dig out the textbook reference to Belleville springs though.......
 

timetraveller

Well Known and Active Forum User
VOC Member
John Emmanuel made up a special jig so that he could run his Shadow engine without the full primary chain case and used a stroboscope to investigate the action of the standard ESA. It was hopless in that on load it immediately goes to maximum movement in one direction and on over run goes to maximum movement in the other direction. This indicates that with the standard 'B' or 'C' number of springs there is not enough pressure. Dick Sherwin fitted one of the Australian adaptors which uses a lot more springs to his Knight. After several thousand miles of solo use we took it apart and it was clear that there had been almost no movement at all. If these two examples are telling the whole story then it suggests that the B/C set up is too week and the Australian set up is too strong (for solo use). Square section springs are readily available but it needs someone to set up a jig and to determine the spring rate with existing set ups before we would know which catalogue item to buy or what spring rate to specifiy for manufacture.

Spring Heel Jack
 

Tom Gaynor

Well Known and Active Forum User
VOC Member
ESA Springs

That's very interesting, if not wholly unexpected. I decided to upgrade to the D set-up. It seems OK, but I haven't looked since i fitted it. I would be prepared to, in a good cause, which I think this is. Simon Linford (who has stripped a lot of Vincents) reckoned that a lot of damage was done by riders exploiting the "low speed pulling power" and working the B/C ESA to death. That sounded plausible to me, so I've made a point ever since of letting it "spin" - relatively speaking - rather than lugging it. Where do we go from here (Trevor.....)?
John Emmanuel made up a special jig so that he could run his Shadow engine without the full primary chain case and used a stroboscope to investigate the action of the standard ESA. It was hopless in that on load it immediately goes to maximum movement in one direction and on over run goes to maximum movement in the other direction. This indicates that with the standard 'B' or 'C' number of springs there is not enough pressure. Dick Sherwin fitted one of the Australian adaptors which uses a lot more springs to his Knight. After several thousand miles of solo use we took it apart and it was clear that there had been almost no movement at all. If these two examples are telling the whole story then it suggests that the B/C set up is too week and the Australian set up is too strong (for solo use). Square section springs are readily available but it needs someone to set up a jig and to determine the spring rate with existing set ups before we would know which catalogue item to buy or what spring rate to specifiy for manufacture.

Spring Heel Jack
 

stumpy lord

Well Known and Active Forum User
Non-VOC Member
hi all,
there is in forty years on an alternative to the standard engine shock absorber, that does away with all the little springs. this was devised by Frank Shillito in 1959,and utilises a few B.S.A. parts. for further details see Forty years on page64 item53.
What it does not tell you, is how you are supposed to compress the spring to get the nut fitted, this you no doubt will realise beat me, and I now have a set of B.S.A. parts that are a available to any body who would like to have a try at this mod. And the best of luck.
cheers norm.:rolleyes:
 

Vincent Brake

Well Known and Active Forum User
VOC Member
Hi Norm Thanx, for your remark, I imagine this BSA spring is made of a wound rectangular steel Or else?? It was rejected by works due to a reason (money, availab??) I would like to see it so I'll buy it from you if possible you can put me an email and I will wire the sum requ. and you can sent it over to Holland then Please. I want to examin every way to solve those "silly little springs" once and for good
Cheers
Vincent

By the way the server is real sloww Graham, it used to be a lot better when it was still in the UK, can I help to do something about it??
 
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