Magneto ignition

BBfangs · #1 (**permalink**) 03-28-2010, 09:14 AM

I recently purchased an EM cobra that was built with a magneto system in it. When you are idling or driving that tach bounces around 2,000 rpm in variation than what I believe it should be at. The seller told me he has tried fixing that tach but his mechanic told him it was because of the magneto and that was the best it would be. Any advice? I know nothing about those systems. Should it bounce around as much as it does? It is a new Pro Comp gauge so I wouldn't think it wasn't that. Is it because the high voltage pulse that is create? I know enough to get into trouble probably.

Rick Parker · #2 (**permalink**) 03-28-2010, 12:01 PM

As far as I know, a magneto can only use a mechanical tach.

brobehr · #3 (**permalink**) 03-28-2010, 02:51 PM

the magnets used in magnetos are very suseptible to corrosion. Could add to wandering idle rpm readings

brobehr

BBfangs · #4 (**permalink**) 04-21-2010, 02:58 PM

I called Vertex and they suggested a Mag Tach Converter. I found that the car already has one. I have a Auto Meter Pro Comp Ultra lite tach. Then the Vertex guy suggested running a ground. I found the car already had one from the mag to the frame. It seems to jump very little at idle but really bounces as the rpm's go up. What might be the next step? Any help would be appreciated.

CobraEd · #5 (**permalink**) 04-21-2010, 03:04 PM

Quote:

Originally Posted by BBfangs

What might be the next step? Any help would be appreciated.

Uh, . . get a coil & distributor

It will be easier to understand / diagnose /work with, overall.

.

BBfangs · #6 (**permalink**) 04-26-2010, 04:30 PM

I am trying to find out what the cost is to fix my problem, if it is enough, I might as well change to a conventional distributor and coil set up. I can't seem to find an old school person who works with magnetos. They are fantastic for the spark that is generated but it is doing a number on my tach.

Jerry Clayton · #7 (**permalink**) 04-26-2010, 04:45 PM

try this guy--I've known him for 50 years--he was doing magnetoes when they still ran 8 carbs-- Lennie Hughes Magneto Service
56105 Barbarrah Drive
Bristol In 46507
Phone 574-293-6688

Tell him I sent you----might be good for a story or two

Jerry Clayton

BBfangs · #8 (**permalink**) 04-27-2010, 06:37 PM

Thanks, I really appreciate it. I will try to drop him a line tomorrow. I have been kicking around an MSD Billet distributor, a MSD 6 AL-2 box , with a blaster coil but all with labor I am expecting $800-$1,000. I was hopnig it would be cheaper than that too fix.

BBfangs · #9 (**permalink**) 05-10-2010, 03:14 PM

I am going to go with my first thought and replace it with the MSD system. I guess that will be my weekend project. Maybe a sprint car guy will be interested in buying the Vertex setup.

FWB · #10 (**permalink**) 05-13-2010, 08:48 AM

BB, do you have a FE motor in your car? i'm changing some stuff on my 427 and i have a MSD pro billet dist. with approx 5000 miles on it i want to sell.
it comes with a new cap and tweeking accessories. i'm in the allentown area.

fred

BBfangs · #11 (**permalink**) 05-18-2010, 04:41 PM

FWB,

Thanks but I don't have a FE motor plus I just bought and installed an MSD system over the weekend. I need to tweak it a bit once the rain stops. Are you going to the Revolution?