The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Greybeard on 16.06. 2019 12:39

Title: Dowty Washers size?
Post by: Greybeard on 16.06. 2019 12:39
I would like to get a couple of Dowty washers for the rocker banjos. I could buy a selection box but would probably never use most of them. When I've looked for specs the washers are shown in BSP pipe sizes. If possible please will you tell me what size I should be looking for, so I can order a few? Thanks.
Title: Re: Dowty Washers size?
Post by: Simon59 on 16.06. 2019 15:13
Hi Neil

I have bought some dowty washers for the same purpose, but I've not tested them in anger yet! They are ID of 11.35mm, OD of 22mm (which is probably the measurement you want) and 1.6mm thick. I think they were cheaper than the fibre equivalents and I'm sure they will work a lot better! I can send you two if you can't get them? The place I bought mine from is just around the corner from where I work and I'm going back there this week to pick up my new oil pipes they are making up for me.

Cheers, Simon
Title: Re: Dowty Washers size?
Post by: Greybeard on 16.06. 2019 15:35
I have bought some dowty washers for the same purpose, but I've not tested them in anger yet! They are ID of 11.35mm, OD of 22mm (which is probably the measurement you want) and 1.6mm thick. I think they were cheaper than the fibre equivalents and I'm sure they will work a lot better! I can send you two if you can't get them? The place I bought mine from is just around the corner from where I work and I'm going back there this week to pick up my new oil pipes they are making up for me.
Thanks for the offer, Simon. I'll try to buy some first. Can anyone relate those dimensions to BSP sizes?
Title: Re: Dowty Washers size?
Post by: JulianS on 16.06. 2019 17:07
Lots of Dowty washers on Ebay in BSP sizes.
Title: Re: Dowty Washers size?
Post by: Greybeard on 16.06. 2019 19:00
Lots of Dowty washers on Ebay in BSP sizes.
Julian, I know, I just need to know the size so I don't waste my money.
Title: Re: Dowty Washers size?
Post by: TT John on 18.06. 2019 10:54
Why? You've got plenty. *smile* *smile* *smile*
Title: Re: Dowty Washers size?
Post by: Greybeard on 18.06. 2019 14:42
Why? You've got plenty. *smile* *smile* *smile*
What, money? Oh yes, I'm rolling in it!
Title: Re: Dowty Washers size?
Post by: RDfella on 18.06. 2019 20:43
1/4 BSP is around .525"
Title: Re: Dowty Washers size?
Post by: Greybeard on 18.06. 2019 22:06
1/4 BSP is around .525"
Thanks RD; that sounds about right for the rocker spindle diameter.
Title: Re: Dowty Washers size?
Post by: duTch on 19.06. 2019 05:10

 Maybe I'm misinterpreting and giving an unneeded egg suck lesson, but the spindle doesn't need sealing it only centres the washer, just the outer of the banjo union circumference needs sealing
Title: Re: Dowty Washers size?
Post by: Swarfcut on 19.06. 2019 08:24
GB.. Plain Fibre, Aluminium or Copper washers  should easily seal the flat banjo against the rocker cover, provided the faces are undamaged. The tapered feed bolt can be lapped to the banjo, ensuring no abrasive enters the oil ways. Then a dab of Loctite on the taper if you have some handy should get you an oil tight joint.

 Swarfy.
Title: Re: Dowty Washers size?
Post by: Greybeard on 19.06. 2019 09:59
I've heard that people use Dowty type washers on the rocker banjos with success. I would like to give them a try. DuTch, surely the banjo ID fits around the spindle OD so a washer that does the same should be the correct size. I would like to hear from someone who has done this and can tell me what size to buy.
Title: Re: Dowty Washers size?
Post by: duTch on 19.06. 2019 11:25

 
Quote
... DuTch, surely the banjo ID fits around the spindle OD so a washer that does the same should be the correct size. ......

 Maybe you mean "the banjo ID fits *snug* around the spindle OD" ? If so, it may be close but I don't think mine does, but maybe also didn't come with my engine...been a while since I had it off but if I recall the wall thickness is *~about* 1/8"- if that...I can't find any dowty washers locally anyway, but as I've said before I made a couple of washers from nitrile sheet a couple of years ago and they seem to be functioning ok (cut a hole to fit the shaft snug to locate them) works for me, but I hope you find what you're looking for.

 nb I remember someone (maybe BSA500 ?) looking into it a year or two ago but the size mentioned didn't relate to anything I could find at the time but 1/4" BSP sounds familiar
Title: Re: Dowty Washers size?
Post by: coater87 on 19.06. 2019 13:28
Hi GB,

 I have done this, and it worked great for me.

 1/4 bsp bonded seal (dowty) washer is what you need.

 But dont cheat yourself, get a small selection. These things work great  on drain plugs too.

 Lee
Title: Re: Dowty Washers size?
Post by: Greybeard on 19.06. 2019 15:36
Hi GB,

 I have done this, and it worked great for me.

 1/4 bsp bonded seal (dowty) washer is what you need.

 But dont cheat yourself, get a small selection. These things work great  on drain plugs too.

 Lee
Thanks Lee.