Mgb misfiring and spitting fire!!!

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Fatbloke
Posts: 381
Joined: Mon Apr 14, 2014 3:50 pm
Location: Royal Wootton Bassett

Re: Mgb misfiring and spitting fire!!!

#11 Post by Fatbloke » Fri Aug 21, 2015 7:36 am

Thanks History.

However as readers of my trials and tribulations will know, I completely replaced everything on my HT and LT systems last year before discovering that my timing was inexplicably 90 deg out :oops: so That is why I was was thinking Carb especially as I have done nothing to it other than occasionally twisting the adjuster knob on the bottom, since I bought the car 14 years ago!. (If it aint broke...)

But as you say, It looks like the black rotor may be the problem.

I've sourced a red one on James Paddocks for 2.95 + VAT. is this the ones you're all talking about?

Sorry Gt67. I didn't mean to hijack your thread, especially with a Triumph. But our problems seemed similar... hope you don't mind too much.
Mike.

A Fatbloke in a Herald

Cambronne
Posts: 17
Joined: Mon Feb 09, 2015 11:16 pm

Re: Mgb misfiring and spitting fire!!!

#12 Post by Cambronne » Mon Sep 14, 2015 10:52 pm

This little tale may be relevant.

I took a trip with the owner of a Dax Cobra replica, fitted with the 5.3 litre V12 from an E-type. Driving through Thorne, near Doncaster, the car developed a spectacular misfire. This involved not just spitting back through the inlet trumpets but actually firing through them. It even blew the forward end of the left sidepipe out of its socket.

We stopped, and as the good folk of Thorne were doffing their tin hats and taking down sandbags, the AA man was called. He quickly diagnosed tracking across the big, circular 'rotor arm' - you could see paths burnt across its upper face.

Of course, the man who can didn't carry a spare Jag V12 rotor arm. He painted the existing one with AA van yellow. This filled cracks in the rotor arm and after its makeover, the original item took us all the way to Harlow. Top marks!

So, eight fewer cylinders but the principle is the same.

Toledo Man
Posts: 201
Joined: Mon Feb 07, 2011 11:55 am
Location: Halifax, West Yorkshire

Re: Mgb misfiring and spitting fire!!!

#13 Post by Toledo Man » Mon Sep 21, 2015 9:28 pm

Always check the ignition before moving on to the fuel system. There are some poor quality ignition parts (not just rotor arms) so make sure you get decent quality parts. Yes, electronic ignition can fail so it is a good idea to have a set of points and condenser to hand to get going again.
Toledo Man

1972 Triumph Dolomite 1850 auto (NYE 751L)
2008 Citroen Grand C4 Picasso 2.0 HDi Exclusive (MA08 WCL)
1995 BMW 318i (M265 PNC)
1991 Toyota Celica GT (J481 ONB)

gt67
Posts: 26
Joined: Mon May 30, 2011 2:24 pm

Re: Mgb misfiring and spitting fire!!!

#14 Post by gt67 » Fri Sep 25, 2015 4:41 pm

its all sorted now. Thanks for everyone advice. After doing everything you would normally do with a misfire with no luck, I had a friend look with me. Somehow there was a short-circuit affecting the points which prevented them sparking. Took them off, put them back on checking nothing metal was touching in the wrong places, and off we go!!!!

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