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Lightning strikes twice?
DavidM - 20/10/08 at 11:04 PM

On my Crossflow I was running a Lucas distributor with Lumenition Magnatronic electronic ignition. About 4 weeks ago the ignition amplifier went up in smoke.

I changed to a Bosch electronic distributor from a Valencia engine (cheers Trev) and now the ignition amplifier on that has failed too.

I'm thinking maybe this is too much of a coincidence and that something else is causing this to happen.

Could it be a problem with voltage regulation, if so given the engine is not currently running, how can I test this?

Does anyone have any other suggestions as to a possible cause? I'm wary of fitting anything else, in case it is just going to cook.

David

hicost blade - 20/10/08 at 11:32 PM

Does it have a ballast resistor?

DavidM - 20/10/08 at 11:33 PM

No ballast resistor, 12v electronic ignition coil.

David

zzr1100rick2 - 21/10/08 at 06:17 AM

If your distributor still has points you could try one of the ignition amplifiers from maplins

We had 24v through ours and it survived ( dont ask )

nitram38 - 21/10/08 at 06:43 AM

quote:
Originally posted by DavidM
No ballast resistor, 12v electronic ignition coil.

David


Could that be the problem?
Was the original amplifier through a ballast resistor and now it is not?
It could be that instead of something like 9V supplying it, you are now putting 12v through it?

r1_pete - 21/10/08 at 07:06 AM

Could heat be the problem? is the unit mounted on a steel / ally surface? mounting on glassfibre can cause an insulating effect and result in overheating.

jollygreengiant - 21/10/08 at 09:59 AM

Amps fail usually for 1 of 3 reasons.

Bad earth.

Excessive voltage.

Over heating.

a good diagnostic tech with the proper break-out box could sort the problem. you just need it running first.

Dusty - 21/10/08 at 10:50 AM

Not sure I remember clearly but I believe I had to run my magnatronic with a standard points type coil, not electronic.

MikeRJ - 21/10/08 at 12:20 PM

quote:
Originally posted by nitram38
quote:
Originally posted by DavidM
No ballast resistor, 12v electronic ignition coil.

David


Could that be the problem?
Was the original amplifier through a ballast resistor and now it is not?
It could be that instead of something like 9V supplying it, you are now putting 12v through it?


Electronic systems don't use ballast resistors. The resistor was essentialy a crutch for the shortcommings of points based systems.

The magnetronic system is designed to be used with a standard points type coil rather than a low impedance electronic unit (as stated in the instructions!). This is alsmost certainly the cause of death of the Lucas system.

As for the Ford system, it's demise may or may not be related. The amplifiers aren't exactly immune from failure on these, I had two go during the time I had a Mk2 Fiesta (first one completely dead, the second causing the engine to cut out intermittantly due to broken connections internaly, putting pressure on the connector would make it work). Also not all electronic coils are the same, you should be using the correct Ford (or aftermarket) one that is matched to the amplifier.

hicost blade - 21/10/08 at 04:08 PM

R u using variable dwell coil?

David Jenkins - 23/10/08 at 08:38 AM

If it's the sort of amp that is screwed to the side of the dizzy, take it off, clean the mating surfaces nicely, then put some heatsink compound on them and re-mount the amp. The heatsink stuff can be bought in a small tube from Maplins.

DarrenW - 23/10/08 at 10:59 AM

I cooked my first pinto amp by fastening to plastic panel. Replacement one was fastened to ali panel. They should also have heatsink paste on the back.