To Resist(or) or not to Resist.......

[ludwig113]

Ok, I know i'm going to open a can of worms here but it has to be asked.

GT6 mk3 1972

I'm starting out with all new wiring and electrical componants, so do i go with a Ballast Resistor or just a Resistance Wire loom...

Are there any advantages to either one? or dis-advantages?

 

cheers paul

[Nigel Clark]

I would opt for a separate ballast resistor, easier to replace should it go wrong. And that's what I've had on my '72 Mk3 since the resistance wire failed.

Nigel

[ed.h]

Many cars do just fine without a ballast at all.  With an appropriate coil of course.  Makes for a simpler ignition circuit.

Ed

[NonMember]

34 minutes ago, Nigel Clark said:

And that's what I've had on my '72 Mk3 since the resistance wire failed.

My '72 Mk3 has a separate ballast resistor because it's what the factory fitted.

[Peter Truman]

I’d go the seperate ballast resistor as Nigel says easier replaced if there’s an issue, also if you subsequently fit an electronic ignition most require the full 12 volts supply so the ballast can easily be bypassed to give the 12v

[Pete Lewis]

+2 for a seperate resistor  

just check  a resisitve coil is  1.5 ohms    the full 12v is a 3 ohm coil

but dumping all  the ballast does make things a lot simpler 

Pete

[PeteH]

Ford. Used the Resistive wire a lot, and it was a frequent fail fault, to the extent that I by-passed them every time I had a different car wether working or not!. Could never understand the "philosophy of thinking" behind it.?

Pete

[NonMember]

47 minutes ago, PeteH said:

"philosophy of thinking"

No thinking, just penny pinching

[PeteH]

11 hours ago, NonMember said:

No thinking, just penny pinching

Unsurprising, given Henry`s, original "Stack-em-high, sell-em-cheap", sales methodology. The Original "Tesco" Principle.👍

Pete

[Pete Lewis]

the ballast idea is down to having minimal design capacity and with cold and a lower battery state it boosts the ign to give a higer HT to help when chranking up.

so the manufacturer saves ££ using a minimal battery rather than one with more cold capacity    

Pete

 

[ludwig113]

Thanks for the reply's, i'll start with the ballast and as Peter said , it can always be bypassed to fit an electronic ignition.

 

cheers paul

[NonMember]

1 hour ago, ludwig113 said:

it can always be bypassed to fit an electronic ignition

There's no need to bypass it. Electronic ignition works absolutely fine with ballasted coils, as long as you wire the EI supply to the right place. The only type that doesn't want it would be a programmed ignition with variable (closed loop) dwell, for which a quite specific coil is needed.

[ludwig113]

1 hour ago, NonMember said:

There's no need to bypass it. Electronic ignition works absolutely fine with ballasted coils, as long as you wire the EI supply to the right place. The only type that doesn't want it would be a programmed ignition with variable (closed loop) dwell, for which a quite specific coil is needed.

thanks for the extra info.

[Peter Truman]

Don't know if this helps copies of my 2 used systems for my Trumps showing the Manufacturers Wiring Diagrams for Ballast Resistor using Accuspark and Luminition Magnetronic Electronic Ignition, offtake for their systems is from the 12v Ignition before the Ballast

[Pete Lewis]

from some years back the modules would run 6 - 18v  and with a poor battery state and a ballast feed would often drop below the 6v threshold 

and things didnt work well  with misfires and non starts     hence the need to jump the module feed to a 12v source which they all seem to advise in beneral 

ive not looked at current requirements 

Pete

 

 

[NonMember]

4 minutes ago, Pete Lewis said:

hence the need to jump the module feed to a 12v source

Think the other way round. Like the Lumenition page that Peter posted says "red wire can be connected to coil positive if". That's a lazy man's shortcut - the fundamental requirement is that the EI supply feed is from a good 12V source. On some applications (those without ballast and without current-sensed tacho) the coil positive is also connected to a good 12V source, so you can, under those conditions, use that. But that's the "jumped" alternative - a direct connection to the ignition switch is the fundamental requirement.

[Peter Truman]

In the case of a non ballast coil/distributor the Accuspark does show the electronic ignition connected to the 12v coil positive

[Gully]

In Peter Truman's first diagram, I'm confused by the 12v 1.5 ohm coil after the ballast resistor - would have thought it would be 6v 1.5 ohm?

Thanks,

Gully

[Clive]

52 minutes ago, Gully said:

In Peter Truman's first diagram, I'm confused by the 12v 1.5 ohm coil after the ballast resistor - would have thought it would be 6v 1.5 ohm?

Thanks,

Gully

I think the manufacturer is saying it is for a 12V car that also has a ballast resistor. All very confusing, but maybe a lot of people don't understand the 6v coil thing?

[Pete Lewis]

there are a lot of coils marked as 12v when they are ballasted 1.5 ohms  as they tend to print the vehicle base voltage not the ancilliary ignition circuit

which can be very confusing and again can end up with the wrong spec coil being fitted

Pete