Technical Different ignition, same problem.

[JollyRedNotSoGiant]

Hi All,

I have a 1966 500F, and I've been through several ignition setups and they keep blowing up.
Car came with the stock setup, which worked fine until it rattled itself to pieces and we couldn't keep it running. Switched to a 123 distributor, which lasted all of about 50miles before cutting out stone dead, no spark at all, tried bypassing all the car electronics and going straight from battery to coil, no dice. Rebuilt the original distributor with new points, coil, cap, and condenser, which worked fine until again it sputtered out, actually looked like there were some gouges in the cap due to loose fitting retaining springs. Gave up on that as a new cap still did not correct the issue. Fitted on of these: https://www.fdricambi.com/en/os1015-electronic-ignition-kit/ along with the recommended coil and voltage regulator and she fired right up. Lasted again about 50 miles. In both cases that the engine cutout with electronic ignition fitted I was coasting downhill in gear.

I have read in another thread that it may be due to heat coming off the engine/exhaust, however I don't see a good work around. Hoping someone could shed some light as to why these things keep blowing up on me, at this point I have spent more time rebuilding ignition circuits than driving the car...

Thanks!

 

[ZaphodB]

I have read in another thread that it may be due to heat coming off the engine/exhaust, however I don't see a good work around.

CLASSIC FIAT 500 D F L EXHAUST HEAT SHIELD METAL Powder coated in Blac

CLASSIC FIAT 500 D F L EXHAUST SHIELD IN METAL - BRAND NEW!! Fits on the shell of the Classic Fiat 500 D F L (Fiat 500R available in other listing) - right side in the engine bay. It is fitted in order to protect the distributor from the heat exhaled from the exhaust. Powder coated in the...

autobellaparts.com

Fits on the shell of the Classic Fiat 500 D F L (Fiat 500R available in other listing) - right side in the engine bay. It is fitted in order to protect the distributor from the heat exhaled from the exhaust.

Or from https://www.ebay.co.uk/itm/265630754414

 

[JollyRedNotSoGiant]

CLASSIC FIAT 500 D F L EXHAUST HEAT SHIELD METAL Powder coated in Blac

CLASSIC FIAT 500 D F L EXHAUST SHIELD IN METAL - BRAND NEW!! Fits on the shell of the Classic Fiat 500 D F L (Fiat 500R available in other listing) - right side in the engine bay. It is fitted in order to protect the distributor from the heat exhaled from the exhaust. Powder coated in the...

autobellaparts.com

Or from https://www.ebay.co.uk/itm/265630754414

Hi, yes I have this piece in there.

 

[the hobbler]

Hi, yes I have this piece in there.

Yes, one of the problems with "electronic" ignition units IS heat---but it is the heat that is coming out of the Thermostat-housing and then blowing over the distributor. Practically ALL of the "electronic" units, irrespective of cost, have a "wilt"(spelt D.I.E.) point of 100C. In fact there used to be label on the side of the '123' distributors pointing this fact out. After a hard run on a hot day, that 'engine-cooling' air can easily exceed 100C. I suffered such a failure, and after giving the problem a lot of thought (whilst drinking many cups of tea), I came up with a relatively simple (though slightly tedious) answer---a 'heat-shield' built into the Thermostat-housing directly in line with the distributor. I don't know if this was the actual answer to the problem, or that I have been extremely lucky, but (touch-wood) I haven't had a problem with my 'electronic' ignition (a simple "Hall effect" unit) for quite sometime. I wrote an article about this for a Fiat 500 club's magazine, and if you would like a copy of that article you are very welcome to it. If you would like to e-mail me direct ( [email protected]) with your address, I will put a copy into the post for you.
I have no obvious answer as to why your distributor should fall apart, but the answer to negating the heat problem to your distributor if you wish to retain "points" ignition, is also simple. Modern "pattern" condensers are, to put none too fine a point on it, crap! (they also do not like heat). The answer to THAT problem is to fit a"Competition" condenser, as supplied by"SWIFTUNE".These condensers do NOT need to be attached to the distributor (and therefore also in the direct line of the very hot "engine-cooling" air), as due to their design (long leads for both supply AND earth) they can be mounted up by the coil, away from the engine heat.

 

[JollyRedNotSoGiant]

Yes, one of the problems with "electronic" ignition units IS heat---but it is the heat that is coming out of the Thermostat-housing and then blowing over the distributor. Practically ALL of the "electronic" units, irrespective of cost, have a "wilt"(spelt D.I.E.) point of 100C. In fact there used to be label on the side of the '123' distributors pointing this fact out. After a hard run on a hot day, that 'engine-cooling' air can easily exceed 100C. I suffered such a failure, and after giving the problem a lot of thought (whilst drinking many cups of tea), I came up with a relatively simple (though slightly tedious) answer---a 'heat-shield' built into the Thermostat-housing directly in line with the distributor. I don't know if this was the actual answer to the problem, or that I have been extremely lucky, but (touch-wood) I haven't had a problem with my 'electronic' ignition (a simple "Hall effect" unit) for quite sometime. I wrote an article about this for a Fiat 500 club's magazine, and if you would like a copy of that article you are very welcome to it. If you would like to e-mail me direct ( [email protected]) with your address, I will put a copy into the post for you.
I have no obvious answer as to why your distributor should fall apart, but the answer to negating the heat problem to your distributor if you wish to retain "points" ignition, is also simple. Modern "pattern" condensers are, to put none too fine a point on it, crap! (they also do not like heat). The answer to THAT problem is to fit a"Competition" condenser, as supplied by"SWIFTUNE".These condensers do NOT need to be attached to the distributor (and therefore also in the direct line of the very hot "engine-cooling" air), as due to their design (long leads for both supply AND earth) they can be mounted up by the coil, away from the engine heat.

That makes a lot of sense, I'd love to read more about it. Short of building some kind of flex shaft to relocate the dizzy entirely, a heat shield makes a lot of sense. I work at a boat dealership and one of my techs suggested fitting a blower to cool the unit... I'll send you my address. Thank you!