The Triumph Dolomite Club - Discussion Forum

I passed you on the Handy Cross (J4) roundabout, I go down the A404, M4 then the A329, Wokingham then Yateley to get back to Fleet!

The M40 traffic was bit sh$$t and it didn't help that it was full of Sunday night a##holes as well!

Condenser quality is rubbish, a well known classic magazine cut two condensers in half, a branded one from I think Lucas and a cheap one, the insides were exactly the same apparently down to some stamping or something.

I would seriously consider a Lumenition setup (£82 from Burtons) and ditch the ballasted system, You still have my dizzy right? So you can install it there and see if it fits ok. I think Jonners describes how to ditch the ballast in the Wiki. The previous Magnetronic setup I had in the MG lasted over 10 years and was still working fine when I sold the engine.

http://www.burtonpower.com/magnetronic- ... tk007.html

I agree, not much point in continuing with condensers and contacts if the quality is not there anymore.

The last magnetronic may have not agreed with my old lucas sports coil, since then I have changed the coil to a Lumenition MS3, and will give it another go.

This time I will check all the resistances first.

Ultimately the 123 Dizzy I have will have to go in, once a bush is machined up, still a few months away.

Mahesh wrote:On the way back from Stoneleigh today I had to detour through central London.

This is because there was traffic on the final few exit's and I changed over to the M4, had to do the same for the A406 and had to come back through Uxbridge.


Do ign coils get this hot ?, and same for dizzy main body ?,
I've never checked before.

Hi Mahesh, Jolly good meeting up again yesterday. It was a good event.
No, From previous experience, my 1850 + Lumenition Optronic system never runs more than hand -hot warm after a long run.
That is with a 12V coil completely unballasted. There does seem to be an ongoing problem with both distributor capacitors and ignition coils. I think one of the problems is that the capacitors go almost short circuit and finally completely short circuit which then causes the coil to overheat and that is then ruined.
Tony.

Bit concerned about how much the existing coil (Lumenition MS3) overheated on Sunday.

Done a resistance check across the terminals
But as I'm shelling out (eternal Dolly phrase) for a Magnetronic, I ordered a new MS4 coil, which measures 1.4 ohms.
What concerns me more is the existing ballast resistor, at the +VE lead to battery positive terminal I'm getting 0 ohms, at any ign key position.
Or am I measuring in the wrong place ?

Doing a bit more checking this morning, and I found the MS3 (blue coil) removed from the vehicle
has about 3/4 fill of oil, and resistance changes depending on orientation, between 0.7 ohms to 1.3 ohms ?,
always thought the liquid inside was non conductive.

This may explain why the car was behaving differently uphill, and downhill, possibly, but no evidence of any leak.

The new coil seems to be filled about 95%, but does not change on the meter readings.

Mahesh wrote:Bit concerned about how much the existing coil (Lumenition MS3) overheated on Sunday.

But as I'm shelling out (eternal Dolly phrase) for a Magnetronic, I ordered a new MS4 coil, which measures 1.4 ohms.

2016-10-28 21.11.03.jpg

What concerns me more is the existing ballast resistor, at the +VE lead to battery positive terminal I'm getting 0 ohms, at any ign key position.

Or am I measuring in the wrong place ?

Hi Mahesh, A couple of suggestions.

If you measure the residual resistance of the DVM leads first you may get a more accurate reading. Just short circuit the test leads together and subtract this reading from the 1.4 ohms you measured first. My DVM leads are typically 0.3 ohms.

The ballast resistor resistance can be measured from the White wire on the fuse box ( becomes live when the IGN is ON) to the White/pink wire on the coil positive when disconnected from the coil itself. This should be about 1.5 ohms

I'm not sure why its measuring 0 ohms at any key position.

That coil measuring different resistances in different orientations is definitely faulty. Into the bin !
HTH,
Tony.

Thanks Tony,

I thought I had the wrong position to check.

My meter reads 0 when the probes are crossed, and my ballast resistor is at 1.7ohms.

Installed the Magnetronic module and MS4 coil, and this time round the module started the car. Last time the module got fried, probably because of the Lucas sports coil.

The difference over the old points is immediately noticeable,
Dry exhaust emissions, even at full choke and over lean carbs
Engine vibration greatly reduced
Rpm more stabe

Will have to do ign timing, and do carbs from scratch, hopefully with better results now.

If your picture shows the dvm measuring form battery plus to coil plus I'm not sure what you are trying to measure.

Its always safer IMHO to look at volts drop across various points to see what's going on when you have the car battery involved.
But with ignition circuits you have a lot of transients, so voltage measurement may not be meaningful....

If points are open you are looking at open circuits, so volts readings are meaningless. With points closed on a ballast system you want to see
about half battery volts at the coil plus. If you see full or near full battery volts your ballast is doing nothing, so your ballasted coil will fry.
....if you see 9 ish volts you have the wrong coil....a non ballasted coil incorrectly fitted.

Jonners

Isn't the resistance of the coil supposed to be measured across the terminals with EVERYTHING disconnected? IIRC a 6v (ballasted) coil should read 1.5 Ohms and a 12v (non-ballasted) coil 3 Ohms.

Thanks Dave, Jonners,

I did measure the coils on their own (pictures further up), it was the ballast I was checking, Tony put me on the right track.

A magnetronic module has been fitted along with a new coil.
All seems well on a two mile drive, however I want to fuse the magnetronic on the trigger lead, may even do the red lead (considering the costs).

Looks like you've got a ballasted coil then. You're gonna end up with everything colour coded. You even had yellow axle stands when we were working on it at the Restoration Show.

The axle stands being yellow is coincidental, bought in 2004.

Toledo Man wrote:Looks like you've got a ballasted coil then. You're gonna end up with everything colour coded. You even had yellow axle stands when we were working on it at the Restoration Show.

The DVM is accurately colour coded too.

Due to bad health, only minor jobs at the moment.

Tidied up washer jets.

Wow! If that's your 'tidying up' I'd like to see your refurb standards.