Strictly looking for feedback from those who have successfully converted to the single coil, not for opinions on why I would mess with the factory dual coil set up.

last year I went through 2 units(aftermarket) from Moss and neither would rev beyond 4500rpm. Reverted to duals and it works again.

is there anything else required for this conversion that would stop revs at 4500? I find it unlikely that both units received could be bad in the exact same way.

is there anything else required to swap to single coil??

 

I've done the single coil conversion on both my V12s with no problem.

The problem, I suspect, is simply the quality of the coils being sold. There's a lot of junk out there. Visit other car forums and you'll find the coils are becoming a problem across the board. We started seeing this 10+ years ago with replacement coils for the AJ16 engines.

I haven't bought a 6093 single coil in a number of years so I can't tell you who is selling the good ones versus the bad ones.

Others will chime in.

Cheers
DD

 

Engel Imports has both aftermarket and “Jaguar” branded, i may try the Jaguar version and see how that goes.

if these are supposed to be plug and play, the brand Moss sells are junk. It wasnt even worth my energy to let them know the 2nd one they sent me was also faulty.

 

I pretty sure they were originally made by Ducellier.

If Ducellier still makes them, and Engel sells them, that would be great. Maybe Engel will open the box and let you know if the manufacturer's name is on the part.

My personal experience in recent years is the Jaguar-labeled stuff is often brand-x but with a higher price and sometimes longer warranty.

Let's hear what others have to say

Cheers
DD

 

Yes, the originals were made by Ducellier. You're looking for a primary resistance of about 0.5 Ohms or less. A coil for a points system will be in the region of 3 ohms.

When measuring resistances that low, you need to take into account the resistance of the test leads on your meter. If you can, touch your test leads together, take a reading and zero the meter; then read the coil resistance. If you can't zero the meter, note the resistance and subtract that from the reading you get when measuring the coil.

 

No issues with converting to a single coil and I have done it on three cars. Removed the wiring to and the second coil mounted behind the grille. Cleans up the aesthetics a bit.

 

thats exactly what I was after, just want less wires if possible.

did you use the jaguar single replacement or other?

 

Its been awhile but I'm pretty sure I would have gotten them from Welsh Jaguar.
You have to look closely on the posts that have two male spade connectors each to see the (+) and (-) indicators.
I had to fashion a female spade connector for the (-) amp wire.

 

I went to single, lasted one day before car wouldn't start. Back to twin coil and all good. I've stopped being influenced to change old parts for new. When its worn or neglected fix, otherwise tread carefully and keep all the old parts, never know when you'll need em.

 

As the years go by I've been taking the same approach as often as not. The quality of new parts is becoming totally hit-n-miss whereas existing older parts have stood the test of time.

Cheers
DD

 

Your original symptoms indicate the root of the problem. Because Math.

At 6000 RPM, a v12 engine is asking for 100 spark events per second, or one every ten milliseconds.
Running double coils, primary windings in parallel, cuts the coil resistance in half, allowing the coils to load faster; Asingle coil setup would require a primary resistance of around half an ohm to charge quickly enough to generate a spark.
As noted, most aftermarket coils are for points-switched ignitions serving fewer cylinders, around 2-3 ohms on average, and cannot "fill" fast enough for v12 application.

If you want to go to a single coil for some reason, be sure the primary resistance is well less than one ohm.

 

Jaguar did go to a single coil in later V12 production, especially on the saloons, as the Series III V12 cars never went Marelli and kept the Lucas ignition until 1992. Nick needs to replicate what Jaguar did.