The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: BSA500 on 30.07. 2018 13:12

Title: Dowty washers
Post by: BSA500 on 30.07. 2018 13:12
Hi
 I replaced my old dowty washers on the rocker feed banjo with the fibre washers because the dowty were old and leaky. Well since I put the fibre ones on it leaks like the Torre canyon. There is oil every where. Could someone please tell me what size the dowty ones need to be because they are sold in BSP sizes and I do not know how that relates to the banjo size etc.
many thanks Andy
Title: Re: Dowty washers
Post by: bsa-bill on 30.07. 2018 13:37
Rocker feed ? is this at the tank end or at the rocker shafts, I have fibre washers on both and no leaks.
My understanding of Dowty washer is a steel washer with a rubber inner, is that what you had on - similar to pic
Title: Re: Dowty washers
Post by: Greybeard on 30.07. 2018 14:06
I've only ever used fibre washers. After the first run, they show signs of leaking. I tighten them, after the next run they show signs of leaking. Eventually they stop compressing and do not leak.
Title: Re: Dowty washers
Post by: duTch on 30.07. 2018 15:00
 I can't find fiber washers the right size, so made some from nitrile sheet rubber- as GB says, they leaked a few times and B-Bolts came loose but after a while they stopped leaking. I also got bored with the B-Bolts vibrating loose, so drilled the heads and made a clip to stop them loosening (too much)
Title: Re: Dowty washers
Post by: a101960 on 30.07. 2018 15:34
Quote
I replaced my old dowty washers on the rocker feed banjo with the fibre washers because the dowty were old and leaky. Well since I put the fibre ones on it leaks like the Torre canyon
Yes, that was my experience, and Dowty washers were the only thing that worked for me. If you can wait until tomorrow I will let you know what size I fitted.
Title: Re: Dowty washers
Post by: Greybeard on 30.07. 2018 19:01

 I can't find fiber washers the right size, so made some from nitrile sheet rubber- as GB says, they leaked a few time snad B-Bolts came loose but after a while they stopped leaking. I also got bored with the B-Bolts vibrating loose, so drilled the heads and made a clip to stop them loosening (too much)

My impression is that the washer compresses, rather than the bolt undoing so your idea may be null and void.
Title: Re: Dowty washers
Post by: BSA500 on 30.07. 2018 19:40
The dowry washers seal right away so no need to keep checking them.
Title: Re: Dowty washers
Post by: BSA500 on 30.07. 2018 22:49
Yes, that was my experience, and Dowty washers were the only thing that worked for me. If you can wait until tomorrow I will let you know what size I fitted.
[/quote]
Yes please
Title: Re: Dowty washers
Post by: duTch on 30.07. 2018 22:50
 
Quote
My impression is that the washer compresses, rather than the bolt undoing so your idea may be null and void.

 I say it's a bit of both, I can't remember when I did the job, but that photo was taken early Feb., and haven't had to touch it since- and that's using the bike most days (Need to let the Gutzzly out for a trot occasionally).

 The clip is more to contain the bolts so I don't lose them... worth saying that fibre washers that size are hard enough to find around here, but Dowty washers more-so, though I did see some not long ago- somewhere *conf2*
Title: Re: Dowty washers
Post by: BSA500 on 31.07. 2018 13:11
Quote
My impression is that the washer compresses, rather than the bolt undoing so your idea may be null and void.

 I say it's a bit of both, I can't remember when I did the job, but that photo was taken early Feb., and haven't had to touch it since- and that's using the bike most days (Need to let the Gutzzly out for a trot occasionally).

 The clip is more to contain the bolts so I don't lose them... worth saying that fibre washers that size are hard enough to find around here, but Dowty washers more-so, though I did see some not long ago- somewhere *conf2*
There are plenty on ebay but the quoted sizes are in BSP so I am not sure which is the equivalent to the washers
Title: Re: Dowty washers
Post by: duTch on 31.07. 2018 14:33

 
Quote
...There are plenty on ebay but the quoted sizes are in BSP so I am not sure which is the equivalent to the washers...

 Yup- ta, I don't really need any at the moment, but shall investigate sizes- I wonder if they come in metric too.  When I saw the ones I didn't know what I needed...maybe was at a swappie.... *conf2*
Title: Re: Dowty washers
Post by: a101960 on 31.07. 2018 15:02
BSA500 Right, I have measured the Dowty washers that I used on my rocker lube banjo fitting, and the size is 7/8" (O.D.) so you need 7/8" BSP Dowty washers.
Title: Re: Dowty washers
Post by: BSA500 on 31.07. 2018 16:45
Brilliant thanks for measuring and in answer to an earlier post they also come in metric sizes on eBay😁
Title: Re: Dowty washers
Post by: coater87 on 31.07. 2018 19:19
 The more you use these things, the less you use fiber or cork or o-rings ot TFPE tape to stop leaks.
 I use them on everything now, not just this bike.
 Bought a large kit of various sizes, and just restock a size when I need too.

 Lee
Title: Re: Dowty washers
Post by: a101960 on 31.07. 2018 19:46
Quote
The more you use these things, the less you use fiber or cork or o-rings ot TFPE tape to stop leaks.
Spot on. I really don't no why anyone would waste money on fibre washers or copper washers when you can so easily buy something that actually works.
Title: Re: Dowty washers
Post by: muskrat on 31.07. 2018 21:14
G'day all.
Just found a supplier with a great range of sizes just up the road in Sydney. http://www.sealingaustralia.com.au/bonded-washers/
Cheers
Title: Re: Dowty washers
Post by: duTch on 31.07. 2018 22:45

 
Quote
..Just found a supplier with a great range of sizes just up the road in Sydney. http://www.sealingaustralia.com.au/bonded-washers/.....

 After my last post on this, I did a search and came up with the same result fairly quickly, but by that time had somewhat squared eyes.. *countdown*
Title: Re: Dowty washers
Post by: duTch on 06.08. 2018 18:41

 To be honest (is there any other way?), I can't see how Dowty washer will  effectively seal in this application except through sheer luck...apart from the bevel in the bolt hole, the only area that needs to seal is the outer edge which is only ~1/8" wide, and that's where the metal part of the washer is, which I wouldn't think would effectively seal without extra help *conf2*

 but hey, if it works- it works