Distributor Modification?

For all cars made after 1945
Angus D'Arcy-Drake
Posts: 84
Joined: Mon May 21, 2012 9:05 am
Name: Angus D'Arcy-Drake

Distributor Modification?

Postby Angus D'Arcy-Drake » Wed Jun 29, 2016 9:57 am

The spring that holds the brush in my distributor cap was so corroded that it snapped the other day. Could the cause of this be trapped ozone gas within the cap? Would the cap benefit from having a ventilation hole drilled in it somewhere? Magneto caps on prewar Alvis had vents, so why don't the post war distributor caps? Would drilling a hole risk ignition of petrol fumes? Is there some other means of distributor ventilation that I have missed? If there is, why do the springs corrode? How can it be prevented?

Interested to hear all opinions on this please. I've been chasing an intermittent misfire for yonks and the corroded spring is all that I have found to be wrong so far.

Posts: 368
Joined: Mon May 21, 2012 10:14 am
Name: Richard Wallach
Location: Melbourne, Australia

Re: Distributor Modification?

Postby RichardWallach » Wed Jun 29, 2016 11:06 am


I too have had rusty carbon brush springs in the cap. That said they were very old springs. I have looked at the fit between cap and distributor body (DVXH6) and there are some gaps and these were with original Lucas parts. Personally I wouldn't be fussed. I have had no issue with new brush and spring currently fitted to the TA21.


Posts: 96
Joined: Tue May 22, 2012 12:53 pm
Name: David Turnage
Location: Colchester, UK

Re: Distributor Modification?

Postby DaveT » Wed Jun 29, 2016 12:32 pm

Re intermittent misfiring - I had this on the Sp25 for about 15 months. Eventually when it failed completely (M25 at night on way home from France!), I found a loose terminal screw in the junction box behind the fuses on the bulkhead.
Dave T
Colchester, UK
sp25 DHC
Jensen 541

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