MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

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 Midget and Sprite Technical - New plug leads

I was doing some checking the other day and checked and cleaned the spark plugs while I had the leads disconnected i checked the resistance 3 were around the same value of 6 kohms but one was 13 kohms so i decided to change them the new set were all around 1 kohms .When I came to start it up it fired allot quicker than it used to and when driving it feels allot different ,I cant belive the difference that they have made.You must not notice the change when it happens slowly over the years of driving.
mark heyworth

One of those things that creeps up on you. Between the hot and cold cycles of running the car, summer and winter weather, pulling them off of the plugs will eventually wear them out. Good to know that you've improved your car with minimal effort and expenditure.
Martin

It's the same with spark plugs, and a lot of other parts, they go well passed their best without notice until they're changed for (good quality) new.

When I asked the manufacturer of my good quality (but not stupidly priced) HT leads (who also make for others to put their brand on) I was told to change mine after about 35k-miles.

As they're inexpensive I change my plugs every two years.

It's a matter of if you want the car functioning or at a better performance level.
Nigel Atkins

A mate recently traced the poor running of his Xflow Caterham to the set of year old plug leads. He dug out the previous set which were years old and put them back on and it runs great again. I know from experience in the past when these cars were common that not all new parts could be relied upon to last.
David Billington

Totally agree, I had one NOS Champion plug crack after short service but not NGK (so far!?), I always check ignition items at each 6 month service at least, or when having to deal with something else nearby or related.

My latest faulty new part was a new choke cable (set), the replacement seems OK so far.
Nigel Atkins

Back "in the day" I had a series of 60s and 70s Fords and Triumphs because they were cheap and I was skint. Every time I bought one I'd change plugs, leads, dizzy cap, points and rotor. Sometimes coil too. It wasn't expensive and it always perked the car up. Always.
Greybeard

Yeap, because previous owners hadn't bothered.

Of course now you'd have to worry about the quality of some of the new parts.


... and you'd want to get rid of the CB points altogether ASAP anyway. :)
Nigel Atkins

That's right Nigel. They sold the cars cheap, partly because they were down on power perhaps, or hard to start. New consumables made such a difference.
Forgot about condensers - changed them too.

To be honest though I'm quite happy with points ignition. Perhaps I've been lucky, but I've never had much trouble with them and I like the simplicity.
Greybeard

After doing 100+ miles today I cant believe the difference I am beging to wonder if the old leads were ever right since they were fitted new 5 years ago, dont think it has ever run this well.
mark heyworth

I'm with Mr G on this one..points and condenser for me. If they are properly maintained then no problem. I too like the simplicity, and it's what the car was designed to run with...I did chuckle when I overheard an owner who had gone "to the dark side" confess to having in his boot a dizzy plate with points and condenser fitted 'just in case'....
Dave
David Cox

More the light side - with bigger brighter sparks.

I've had electronic on my current midget for 10 years now that means I've missed the 'joy' of about 40+ lots of checks and fiddling and farting about with points - but I have gained fit 'n' forget consistent reliable better running and performance and I carry nothing in the boot.

Each to their own.
Nigel Atkins

I would tend to think it will be the plugs that make the difference rather than the leads.
Oggers

The plugs were checked and cleaned so unless they were well out they may not be the only contributor to the improvement.

I've previously proved to a doubting specialist that new better quality HT leads can improve performance over standard quality leads. Info in the Archives here.

A faulty or poor performing HT lead in an otherwise good set can cause all sorts of issues and below par engine performance even if the plugs are new and in top condition.
Nigel Atkins

Nigel

Mark's first post suggests the plugs and leads were done simultaneously. Therefore you don't know for certain whether it was plugs or leads which contributed the most to the improvement - but my money is on plugs, especially if they are incorrectly gapped or dirty.
Oggers

Mark (+ Mark),
I agree as plugs and leads were changed together we don't know but based on my experience of plugs and HT leads and Mark's first post my money is on the leads.

One way to find out, if the old leads are still available in the condition they came off the car, is to put the old leads back on with the plugs cleaned and gaps checked again to eliminate the plugs, if the car runs rough again with the old leads then put the new HT leads back on to confirm if it is the old leads mainly at fault.

We could all three meet in Lancashire to oversee the tests and confirm the results. :)

Or if Mark wants to, I don't mind trusting Mark and just placing a £2 bet with you, loser drops £2 into a charity box of the other's choice.
Nigel Atkins

I did not change the plugsjust checked them and only wiped them as they seemed ok
mark heyworth

Sorry Mark, I mistyped, in the previous post I put you'd checked and cleaned them.

I was probably thinking and/or meaning you'd changed the condition of both the plugs and leads, plugs by cleaning (and gapping) and leads by fitting new.

But - if you only wiped the plugs then that would suggest it was the leads at fault.

If you were able to do the test with the old HT leads it would be great as (the other) Mark would hate to say I might be right and hate to give away £2 - not that he's agreed to the bet and if he did he'd say we'd colluded to fix the result, unless you said it was the plugs. :)

Nigel Atkins

No you can't claim anything Nigel. We are now in receipt of further information which changes the conclusion!
Oggers

cant try the old leads as one of the ends has come off and on closer inspection they are not crimped very well.
mark heyworth

Oggers you should go into politics!

It almost sounds like you might think it might have been mainly the old leads at fault, all without agreeing with me of course. :)
Nigel Atkins

Mark,
I was only having a laugh about retro testing. Unless your previous leads were very old it does suggest that better quality leads can be a good idea.

I've seen where someone reported the AccuSpark leads they got as part of a bundle or kit came apart on initial installation and the fit of the boots wasn't good.


Nigel Atkins

After 20 years in aircraft development I like to know a reason for failure aswell as a solution.So my conclusion bad leads poorly made.
mark heyworth

Ironically I might have a HT leads story to add later in the week.
Nigel Atkins

This thread was discussed between 02/08/2018 and 06/08/2018

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.