Ballast resistor required?

Please excuse the ignorance of a noob!


I was thinking on upgrading my ignition system to a mallory duel point distributor and mallory hyfire 6 ignition unit to get the best performance and mpg from my rover 3.5 V8 twin carb engine.
The existing system has a lucas 9BR ballast resistor and lucas coil.
Just wanted to know if the mallory setup requires a resistor?
If so, would the lucas resistor and coil be suitable for the new mallory setup?

I dunno,

but without seeing your ballast i dunno if i could resist her or not.





Ill get me coat:doh:

My P6 came with a mallory twin point running a ballast resistor and normal ballasted coil

If I were buying one then I'd be going pointsless though. But as it came with it...

Have you considered changing to Lucas 35DLM8 dizzy with electronic ignition?

Should be cheap, available and fairly reliable, but perhaps not as fabulous as the mixed results Mallory...?

well its a simple answer, if its a 12v coil you will be running you dont need a ballest resistor if its a 6v coil you will be running you do!

what year is the engine? if its 76 or earlier the later magnetronic dizzy wont fit noisy but if its later then it should be ok and is the cheapest way.

I wouldnt bother with mallory, heard lots of horror stories and bloody expensive- also quality consumables for them are hard to come by, most bits for them are ****e quality.

if you cant us magnetronic I would use lumention. Great when fitted correctly, I did mine myself and it works a treat.

I have heard mixed thoughts on mallory. Some say it is the best setup you can get and others say they are unreliable.
One reason I considered a mallory dizzy was that I had toyed with the idea of converting to LPG and read that the mallory dizzy produced a better intensity of spark and had less wear with duel points.
The second reason I thought about the mallory upgrade was that I got offered a new Mallory dizzy for £75.

Does anyone know if the 35DLM8 dizzy with electronic ignition would be suitable for LPG and what it's advantages might be?

I think the engine is roughly an 88 SD1 as it has a date on the alternator but I realise this could not be the origional. I can't see a clear stamp on the block either.
I will take some pics of the engine and post to see if anyone can help identify it for sure.

35dlm8 is fitted standard to late model 3.5 and 3.9 with carb and efi.

thus, parts are available and cheap, and it is proven to work with lpg.

rpi offer the variable timing unit for lpg which works ok i think although it could be a bit snake oil.

Ok, It's been a while but I've finally got her up and running!! :clap2:

I have stuck with the origional distributor. Think it is the 35DLM8 (only has one wire coming from the side of it and no box) correct me if I'm wrong!

The ballast resistor that is on it is a Lucas 9BR ?
It wasn't wired up when I bought the truck and since starting the truck for the first time the coil overheats like hell!! I presume the BR is the issue here?
It doesn't seem to have any markings on any of the 6 spade terminals to indicate where they connect with.
Can anyone help with this?

read my last post on this thread and that will tell you if it should have a ballest resistor

For lpg I would fit lumention over points. its easy to fit and maintainance free. also I would not use mallory as good quality parts are an issue for them so I am told by a local user who has ended up takin his off!

Will have to double check if it's a 12V or 6V next time im at the motor.
Not decided on LPG yet so will probably just keep this ignition setup for now.

Just found this on another forum. Would you agree??

'As for the ballast resistor, these are used to drop the normal 12V supply to 6v except on start-up (when they are by-passed with a direct supply normally using/from the starter solenoid) to give a fatter spark when starting. They are fitted in series in the coil supply. On Sd1 the resistor is part of the silver 2"x3" amplifier box (which you don't need). Given a 'decent' battery (little voltage drop on starting) I can't really see any advantage of running a 6V coil/ignition system these days - and your DLM8 distributor NEEDS to run at 12V anyway. In the short term there is no worry about running a 6v coil at 12v, it will just get a bit warm, in the longer term it will fail eventually.'

yes, but it can fail quickly especially when its 20 years old to start with

Think I would have to buy a new coil anyway, but they are reasonably cheap.
I think it would be 6V (will check tonight) on just now as it is seriously overheating!
That said, it was overheating when I was cranking the engine over endlessly from the starter as it was very reluctant to start. (got it to start from a tow in the end)

In your opinion wich do you think is the best plan of attack? A new 12V coil and leave out the BR or keep the 6V coil and keep hunting for wiring diagrams for the BR?

HIGHlux said:

Think I would have to buy a new coil anyway, but they are reasonably cheap.
I think it would be 6V (will check tonight) on just now as it is seriously overheating!
That said, it was overheating when I was cranking the engine over endlessly from the starter as it was very reluctant to start. (got it to start from a tow in the end)

In your opinion wich do you think is the best plan of attack? A new 12V coil and leave out the BR or keep the 6V coil and keep hunting for wiring diagrams for the BR?

Click to expand...

A ballast resistor is easy to wire up,the 12v feed from the ignition switch goes to one end of the resistor and the other end of the resistor (9v) goes to the + on the coil,then put the wire from the little terminal on the starter also to the + on the coil so it gets 12v when cranking

Mine used to go through points like hot dinners so i changed it to a ballast system and its fine now

what igntion system have you got?

if you have points maybe stick with the 6v coil and ballest but if its anything else lucas it might be worth going 12v as its probably cheaper and easier