Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Arcing spark

I thought today being dry and bright I would take the A out for a run. It has been several months without starting and eventually a bit of life but no start. I then noticed arcing between ceramics and steel body of #1 plug. Replaced with another and the car started. Took it for a short run and filled up with fresh fuel. Does the arcing suggest that the plug is faulty and should be ditched?
Brian Paddon

It will have a crack in the ceramic and humidity will have worked into the insulator. It may be OK when warm, but sooner or later it will fail completely. I once had a batch of NGK that failed as soon as the socket put any side pressure on the insulator at all. I junked the entire box. I would suggest it's better to fit a full new set - they are cheap enough
Dominic Clancy

Wouldn't have resistor plugs in there by chance---
The combination of solid plug leads and resistor plugs will cause that--arcing down the insulators--specially if the plug gaps are a bit wide
Nothing wrong with NGK plugs---maybe a new plug socket would help
William Revit

Thanks Dominic/William for your comments.
William I use NGK BP6ES plugs with original Lucas caps and copper leads. So maybe a dud plug. I have used NGK plugs for years. Seem to be a good choice. Think the gaps are as book suggests but will check tomorrow.
PS Came to Taz a few years back wish I had my A to travel around your beautiful island.
Brian Paddon

Plug socket has been fine since I junked that box of NGK, thanks !
Dominic Clancy

Must be the operator--------couldn't possibly be the plugs----lol
William Revit

What ever happened to "Champion. and KLG " brand Spark Plugs?
The world drove on these for years.
Perhaps it was like the demise of the English Motor Cycle Industery.
Those old tins that Champion plugs came in---are just so handy.
Just remembering---"when"
I.W. Cowen.

Haven't seen KLG pluds for a while Ian and Champions have turned into a bit pf a hit and miss thing, in Aust. anyway -I 'think' it depends on where you live now as to where your champions are made
Haven't got any tins Ian but have an old pull apart plug

William Revit


William Revit


Really---"A Hit and Miss thing---"

7/8" Plugs like those used to be used on Fordson Tractors, back in the late 40's ! ! We used to take them apart, and service them!
Great memories! !

But you already know, how old I am ! !

Cheers, Nuffield.
I.W. Cowen.

The Fergie TE20 on which I learned to drive was a dual fuel version and used plugs like those. Started on petrol and then switch to TVO (paraffin aka Power kerosene in Australia)
Dominic Clancy

A grey Fergie--what a great little tractor they were--are
William Revit

Champions are still around and popular. I run them in more than half of my cars including the MGA, never an issue.

I would throw away the plug that was arcing. They are too cheap to take chances on a breakdown.
Steve Simmons

Steve-You're lucky, the Champions we get here had a major quality dive about 5-6 years ago when they changed supplier and weren't very good
Even the black Motorcraft plugs here had a change of manufacturer and were made --somewhere? other than the original black base USA plugs and weren't reliable at all
Ford here released a budget range of plugs around 2/3 price and weirdly they turned out to be excellent plugs and were repackaged Nippon Denso or Denso --good plugs

NGK seems to be best value plugs here at the moment and a good available heat range
William Revit

I only ever use NGK, having had problems with other brands.
Dave O'Neill 2

The NGK's have performed best in my 79-B. Nothing against other brands, but each engine has its own "preference" You just need to choose which ones your engine "likes" best.


79 MGB
gary hansen

This thread was discussed between 20/01/2020 and 26/01/2020

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.