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Leaky distributor cap - Printable Version

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Leaky distributor cap - Adrian Payne - 14-01-2020

Hello All
My BLIC magneto cap is absorbing moisture and making it very hard to start. Resistance as low as 20 Meg, leaking the HT spark.
Baking in the oven restores the performance. Is there a way of waterproofing the bakelite or using EHT spray etc to prevent absorption. New caps do not appear to be available.
Many thanks.
Adrian.


RE: Leaky distributor cap - Robert Foreman - 14-01-2020

Adrian,
 some Blic distributor caps are a brown and some a reddish colour. I suspect the reddish ones were painted with a red insulating varnish when new. 
Once you have cooked the cap and removed as much moisture as you can. You can  use a hygrometer to check how dry you have got it. 
  Then I would try a high voltage insulating varnish. Varnish inside and out and when completely dry clean the contacts inside.
   Hope this helps.


RE: Leaky distributor cap - Greig Smith - 14-01-2020

Adrian a good soaking of DWF (De Watering Fluid) aerosol spray should sort it out, it's made for spraying electrical stuff, I've soaked dizzy's with it, inside the cap as well. It dries off and repels water.

Aye
Greig


RE: Leaky distributor cap - Adrian Payne - 14-01-2020

Many thanks for the suggestions.
I have read somewhere that if a spark tracks across an oily surface then a carbon track is left behind which can never be removed. Most dewatering products seem to lubricate as well so could they be oil based?
I think I will try the varnish first and see how that goes.
Many thanks.
Adrian.


RE: Leaky distributor cap - Ruairidh Dunford - 14-01-2020

Does anyone know if these type of caps could be 3D printed?


RE: Leaky distributor cap - Adrian Payne - 14-01-2020

Hello Ruairidh
The shape would not be a problem, but the dielectric strength of the printing filament might be a problem.
I once read an interesting article about a group trying to recreate distributor caps for the liberty engines. They tried several resins I believe without success.
Adrian.


RE: Leaky distributor cap - Ruairidh Dunford - 14-01-2020

That’s a shame, maybe one day soon...


RE: Leaky distributor cap - andrew34ruby - 15-01-2020

(14-01-2020, 10:50 PM)Adrian Payne Wrote: Many thanks for the suggestions.
I have read somewhere that if a spark tracks across an oily surface then a carbon track is left behind which can never be removed. Most dewatering products seem to lubricate as well so could they be oil based?
I think I will try the varnish first and see how that goes.
Many thanks.
Adrian.

Any varnish type product is likely to cause problems. After a few years it is likely to slightly crack, peal, etc. And it's then difficult to remove the 'varnish'. Holts wet-start used to do this, it was a very temporary fix. Holts damp-start was an oily water repellant and never gave problems. Thirty-odd years ago I used WD40 and Duck oil on thousands of old distributor caps with long lasting success.

If you can see a carbon track, just sandpaper it away, then spray.


RE: Leaky distributor cap - Robert Leigh - 15-01-2020

It may be worth trying Donald Day. He does stock new BT-H caps, so possibly he has others as well. Sit down before he tells you the price!
Robert Leigh


RE: Leaky distributor cap - Colin Swinbourne - 15-01-2020

I wonder...maybe it’s not possible (currently) to 3D print them, but what about using 3D printing to create cost effective tooling to allow them to be cast / injection moulded?