Manky's Pop.

[tbone]

beware of resin compounds in silver foil, you`ll have the drug squad after you!
Seriuosly tho, we need to identify the distributor that you have, i believe rover experimented with 3 different ones in the late 70`s, early 80`s, this is around the time that electronic ignition was first being introduced.
So the first question is, points or no points? My guess is none. And so, does this look familier?

[tbone]

an old pic, sorry

Now for a techy question for you lot. There's an electrical fitting in the ignition circuit we can't identify. I'll grab a photo tomorrow, but not much to see really. It's a block of clear resin, wrapped in aluminium sheet, with 3 wires going into it. One goes to, (or maybe comes from), the + terminal of the coil. One to the - terminal & branching off to the distributor & one straight to the dizzy. Any ideas? Is it a ballast resistor? Seems to be acting as a switch in the circuit as without it connected there's no spark at the plugs. Can I replace it with the coil I bought for my trike, which has a ballast resistor piggy backed onto it? It's an ugly lump of ally & resin so would be nice if we can get rid of it. My engine's a late 70s SD1 Rover by the way, with a P5 or P6 gearbox & possibly Range Rover heads.

[Manky Monkey]

Hmm, I'll need to take a closer look at our motor tomorrow. Really not sure what we've got, but does look like that's a ballast resistor then doesn't it. Haven't even popped the cap on the dizzy yet so no idea if it's points or leccy.
We messed about with the 4 left hand pipes again this afternoon. They're never going to quite match the tight bends of the other header, but we've done what we can with the assorted bits of tube we had. I've brought them home to clean 'em up a bit in the shed over the weekend. We're thinking maybe we'll wrap them in black exhaust bandage as it'll disguise any differences in profile & be in tune with the 50s hotrod ethos.

[Manky Monkey]

Yes, of course we had to fire it up again before we took the pipes off!
Sounds completely different than it did with the cast Rover headers on. Got a real bark to it. We plan to run a pair of long "Smithys" silencers, (like long "Cherry Bombs"), under the body on either side, exiting under the pick up bed tailgate.
See you on the dirt Shaun! 

[tbone]

The dizzy will have a number stamped into the casing, usually round the back! if thats the setup you have it sounds like its already been cannibilised. should have the six wires attached, one feeds the tacho, the other two override the resistor when you turn the engine over, giving increased power to the coil for a short burst. When the starter disengages the resistor cuts back in. would have looked like this at some point....

[Manky Monkey]

Yup, that's the resin/aluminium thingy we've got. The wires are plugged in with DIY crimp on terminals. How does the over-ride bit work? Can I use the ballast resistor I've got in the shed?

[tbone]

Time to look inside the thing. NO! put that hacksaw down, i`ve got a pic somewere 
The balasted ignition circuit is to improve the spark when starting.

In a nutshell, during cranking,the battery voltage drops to around 9v, due to the heavy load being drawn by the starter motor. So they use a 6v ignition coil and feed it through the ballast resistor. Therefore the coil gets a 6v feed to it because the Ballast resistor drops the voltage down. Resistance of the resistor is equal to the resistance of the primary windings on the coil.
When you turn the key and the starter engages, the starter relay or solenoid, provides another 12v feed into the resistor and due to the way its wired,the ballast resistor is "by-passed" therefore feeding 9v to the coil during cranking. As soon as the engine fires and you let go of the key, the solenoid disengages the by-pass of the ballast resistor and the coil sees 6v again.
Still not answered your question though have i....in theory, yes you can use the one in the shed.
Just have to figure out which, of the 3 wires you have left, does what, and why ony 3, a fourth would make more sense, because then...
One to + (coil)  = 9v from resistor
One to - (coil)   = Dizzy pick up (branch to feed tacho)
One to dizzy     = pick up feed   (poss 12v)
but a fourth is needed to supply 12v into the resistor

[Manky Monkey]

Hmm, I'd like to say I understood that, but I'd be lying.
This is what we've got. Distributor. No points. No discernable numbers.

[Manky Monkey]

Leccy box thing.
3 wires going into one side only.

[Manky Monkey]

I need to find a remote oil filter for the motor too. The standard set up sits right where we want to put the steering box, so I need to relocate it to the other side of the chassis. Or build it as a left hand drive!

[tbone]

Looks to me like its being used as a junction box. i think you probably get a direct 12v feed. unless the resistor is between the white/green and red wires, that would then suply reduced current into the dizzy.
White/green wire would supply voltage from coil +
Black/white  wire would be the trigger feed ( and tacho which is no longer used) goes to coil -
red wire would supply power to the dizzy

[Manky Monkey]

So can we run without it & if so, which wires should go where on the ballast resistor/coil I've got in the shed? Only one feed into the new resistor & one out as far as I remember.

[tbone]

Having slept on it and bearing in mind i have no info on the currently used coil, heres what i`d do.
First, see what the voltage is at the + side of the coil, gotta assume its 12
second, confirm the voltage for the lead that goes direct to the dist, (red one?)  <12v confirms that the resistor is placed between those two connections, giving 12 volts input and ?? volts output.
( 6ish volts means you cannot use your new coil, as that was for the reliant engine and so it would output 9ish volts) Your red wire needs to be 9ish volts in order to use your new coil/resistor, In which case, you would set your new one up like so...
WHAT A CRAP DRAWING!! ok in words...
12v into one end of the RESISTOR ---other end (9v out) connect to COIL + terminal
RED WIRE (direct from dizzy) connect to COIL + terminal   (this is the power in lead for the electronic trigger)
BLACK / WHITE WIRE connect to COIL - terminal              (this is the output wire from the electronic trigger)

[Manky Monkey]

Still pretending I know what you're talking about.
O.K, not a top priority at the moment, but will refer back to that when we get that far. The coil I've got was bought from a trade stall at a hotrod show, so not a Reliant one, just yer average 12v jobbie I assume. Thanks for that TB.

[tbone]

you know it works as it stands so just tidy it up a bit  , as the old saying goes, if it aint broke dont fix it