Can anyone tell me if it would make any difference to performance or fuel consumption if I change the coil in my 66 F100 240 (all other things being equal)? The reason for asking is that I see the "performance coils" being advertised.

When I set the ignition timing on my truck the other day after replacing the points and spark plugs, the induction coil of the strobe seemed to struggle picking up the signal. Almost as if the spark is weak. The truck goes very well though.

I always thought that a coil either works or it doesn't.

 

Coils can do funny things right before they go. It's most likely fine. As for a Proformance coil you might notice a smoother idle an maybe a slight increase in milage but not the 25% some claim. Are they worth it, Yes are they a must, no.
Most coils are oil filled and MUST be mounted vertical to keep the windings cooled in the oil. So many times I've been at the race track to see guys tring to find an ign problem only to see there coil on it side. The hi-voltage wire going to the distrib cap most be on top ponited toward the sky.

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They also need to be kept on the air stream to improve cooling.
I've seen coils overheat and burn up simpley because a chrome cover was placed over the coil or it was mounted out of the air stream.
I like to put mine right up front on the manifold, or utilize an extra accesory hole of front of the head.

 

Exception to the vertical mount coil is MSD's High Vibration Blaster Coil PN8222, which I learned of only after installing a standard (vertical mount) Blaster. According to MSD literature in my installation instructions, the PN8222 "can be mounted in any position due to its epoxy potting compound."

 

I was intrigued by the assertion that oil filled coils MUST be mounted vertically. 240 and 300 sixes had them horizonatally for many years, stock.

I called Pertronix today and spoke with one of the engineers. He did confirm that vertical mountings do improve cooling slightly, but he stated that they have not had excessive trouble with their Flamethrower I and II coils when mounted horizontally. They have no recomendation in place to mount vertically.

So at least for Flamethrower coils, the need for a vertical position is not correct. I believe stock Ford coils are oil filled as well, and they are also horizontal in 240/300 at least. I have never heard of that being a problem.

As to Marnus' original question -- I don't think that the "performance" coils will give you too much more than a good stock coil. But when coupled with a duraspark or pertronix unit, the larger gap will give better ignition and many folks get slightly better gas mileage too. The debate about points versus electronic has been held lots of times, with the usual consensus being that points are slightly more secure and reliable in the hands of an experienced driver that can adjust them if need be, but for pure performance, the electronic units are meaningfully superior.

Beats me what an Ignitor II and Flamethrower would cost in S. Afirica -- in the USA I think it is a very good investment. Or a duraspark, if you can stand the change in appearance and clutter under the hood.

 

Thanks for the posts Guys.

I never knew that you had to mount the coil horizontally either. It is the stock Fomoco coil. I am going to ghange it to vertical just to see if it will make any noticeable difference.

I will see if I can get any prices on a Flamethrower or Ignitor II locally. Preparing myself for a shock!

I have heard of the Pertronix and Duraspark systems before and have no clue about them. Don't bother to respond, I will do a google search as well as search this site.

Kind regards
Marnus