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MG MGB Technical - Anyone recognise this?...

Dizzy!

This distributor came with the car and I'm struggling to figure out if I've wired it up correctly as there are no instructions that came with it.

I've wired the red wire to the negative side of the coil as the workshop manual says a dizzy should be and the black wire I've taken to earth.

No sparks yet!

So, if anyone recognises the make of the internal (Petronix or similar) should their be a control box (similar to lumention system) incorporated in the mix somewhere.

Any help would be greatly appreciated.

Thanks

Andrew

Andrew McGee

See response on midget side
Dave O'Neill2

Thanks Dave.

A
Andrew McGee

Hi Andrew

I think the red goes to ign coil + along with the power from the ign switch, and the black goes to ign coil - This is how the Accuspark unit is connected.

Ronnie
RA Potter

Thanks Ronnie, yes that's what Dave had posted on the Midget side.

Will do that today and hope I've not fried anything by connecting it incorrectly.

Crossed fingers.

A
Andrew McGee

Fried chips it appears :-(

But I'm going to go through the ignition wiring and double check that something else isn't amiss.

A new Accuspark/Petronix dizzy isn't that much I'm told!

A.
Andrew McGee

Andrew

I can't see how you could have fried anything by connecting it the way you did. Some logical fault finding is called for.

I assume that the trigger unit must also need an earth/ground and presumably gets this through the dissy. Can you check that the dissy has a good ground connection and that you definitely have 12v at the coil +ve?
Dave O'Neill2

Dave.

I was thinking about going through the whole wiring set up as there is something amiss with how the loom has been put in (again by PO) as I've spotted that the Ignition light is permanently on (good job we've disconnected the earth everytime we've been working on it) and when the key is removed the fuel pump continues to tick...

something is certainly not right with it!
Andrew McGee

What sort of fusebox is fitted - 2-way or 4-way?
Dave O'Neill2

Hi Andrew

I know that wiring is correct for the Accuspark as I fitted a new one this week. I paid 49.95 for a 25D distributor. It works fine and the quality looks OK. I think this was a special offer from Watford Classic Cars as I see the price is now 59.95.

Ronnie
RA Potter

Guess who wins the muppet of the year award.... that'll be me then!

Memo to self, don't mess with electrics at all, although there are mitigating circumstances m'lord!

A certain mate of mine who lives locally who is an AutoElectrician and races MGs does a little modification to his Alternators and then includes another wire in his looms. Both my race midgets had this mod in them and my sons has it too.

So when I saw the same terminal on the Alternator and a spade connector which aligned perfectly with said terminal, in my mind they went together!.... WRONG!

Turns out I'd put a permanent feed straight to the coil and then into the Petronix/Accuspark dizzy!


So tomorrow we'll be removing the current Dizzy and replacing it with one from my RB engine (providing they haven't changed the dog drives and mounts etc). This dizzy has a Lucas AB14 amplifier as part of the set up and I've already been online to check how that is wired up: white to positive and white/blacktrace to negative.

So that's what we'll be doing tomorrow!

I don't mind these set backs so long as it's a learning experience...

A
Andrew McGee

Dave, it's a 4 way fusebox.

Ignore the 66 date of the car, the loom is a 71 and negative earthed.

Will see if I can get replacement internals for the fried dizzy and have it as a spare or even put it in the road midget.

A
Andrew McGee

The reason I asked about the fusebox is that if it's a 4-way, it is possible to fit the wrong way round, which gives a permanently live ignition circuit.
Dave O'Neill2

Yes, I've had experience of that particular thing also (on the road midget)... told you I was a muppet! :-)
Andrew McGee

It runs!!!!!! YEEHAAA!

SO this morning I stripped out the dizzy from the RB engine and it's amplifier an AB14 Lucas module. After cleaning all of them up they were fitted following instructions I found in the t'interweb.

After a couple of cranks over the car fired up and ran with a bit of coaxing. Smoke started billowing from the manifold side so I switched off. It was only the black paint from the heat shield "settling in".

No oil pressure was registering whilst it was running so thought I best sort that out before risking anything further.

I took off the flexi pipe and blew compressed air through it and that was fine. Then decided to bypass the standard oil pressure gauge and fit one of our spare gauges for the race cars and cranked it up again. It wouldn't fire but we got a decent reading on the gauge.

A bit of fiddling with the dizzy with a degree or two (not scientific) of clockwise movement I cranked it over again and it fired up.

The alternator sings away far too loud so that is going to be swapped for another of our spares and then it will hopefully be quiet enough to tick over without scaring the dogs and birds away... never mind the neighbours.

So left on the list to do, bleeds brakes and clutch, fit bonnet, swap wheels and tyres to some road legal rubber (I can't find the DOT or E mark on the Dunlop Formula R's that are currently fitted!), then it's off for an MOT and hopefully within the year since getting it we've taken a car from a shell, stripped it bare, painted it and built it up.

A nice sense of satisfaction and achievement to say the least.

A.
Andrew McGee

Hopefully tomorrow we'll get the BGT off for its MOT and then straight to the Post Office for a tax disc and we can use it this weekend.... depends on the MOT of course!

Crossed fingers.

A

Andrew McGee

And another...

Andrew McGee

Big Smile... it passed!

A
Andrew McGee

This thread was discussed between 16/05/2013 and 23/05/2013

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