Coils

[moggyadventurer]

Hi can anyone recommend a good coil supplier?

I know simonbbc is suppose to be quite good.

Or is it worth the extra to buy a lucas coil?

thanks in advance

[chrisryder]

i'd avoid a lucas one. ok the one i've got on now is working fine and has been for a few months, but the first one lasted 10 days before mis-firing and back-firing like hell! that's all well and good if, like me, you got it from a good supplier and they exchanged it for me, but a pain if you just pick one up from somewhere! The prince of darkness lives on!

[chrisryder]

i should mention, mine was a Lucas Sports Coil, not a 'Standard' coil, not sure if their quality spans the whole range!

[simmitc]

Visit the local scarp yard (if any still exist ) and pick up an old Lucas coil from any 1960-75 British car (but not one with a ballast resistor) and it will last forever. Modern ones, well.....

[alex_holden]

I had a run of bad luck with coils a couple of years ago. The one that came with the car developed a fault that took a while to find through a process of elimination. She intermittently misfired but only when accelerating hard above 40 mph - that made overtaking rather dicey. Because I'd believed the advice 'it's never the coil' I had already replaced every other ignition component before I tried the coil.

I replaced it with a Lucas one that was unused and a bit over a year old (it was kept in the spares box in the boot). It died completely after a couple of weeks on the way to the National. Luckily she started misfiring just before a service station exit and I managed to coax her up the ramp and coast to a halt in the first available parking space! I had another new Lucas spare in the boot so I swapped it over and carried on my way. I later cut the dead one open and found that one of the wires inside had broken at a solder joint.

While at the National I bought about four used coils from the traders there, after measuring the primary winding resistance (I found several dead ones for sale that way!). All but one of them either developed a misfire or leaked oil all over the dynamo within a few days/weeks of fitting them. The last one is (touch wood) still working fine 10,000+ miles later.

So, what advice can I give? Sometimes it *is* the coil; don't trust a new one even from a formerly reputable make (I don't think they are made in the UK to the same standards any more), don't trust an old used one from an autojumble (perhaps it was removed for a reason); carry a known-good spare (and the tools to fit it) in the boot at all times!

[LouiseM]

So, what advice can I give? Sometimes it *is* the coil; don't trust a new one even from a formerly reputable make (I don't think they are made in the UK to the same standards any more), don't trust an old used one from an autojumble (perhaps it was removed for a reason); carry a known-good spare (and the tools to fit it) in the boot at all times!

Useful advice but if you can't trust a new coil, an old coil or an unused NOS coil where do you get a known good spare from in the first place?? If your coil is working well and causing no problems then you'd keep it where it was rather than put it in the boot. And if you happened to have a known good spare you'd keep hold of it rather than sell it!

[bmcecosse]

Ha! I still say it's 'never' the coil ! Of course just sometimes it IS the coil, but eliminate everything else first. And I agree - avoid jumble coils. If you buy from the likes of Hellfrauds - you should at least have some warranty to fall back on. As far as I know my car is on it's original coil - mounted on the inner wing to avoid vibration and heat - NOT on the engine.

[alex_holden]

Useful advice but if you can't trust a new coil, an old coil or an unused NOS coil where do you get a known good spare from in the first place?? If your coil is working well and causing no problems then you'd keep it where it was rather than put it in the boot. And if you happened to have a known good spare you'd keep hold of it rather than sell it!

NOS from 10+ years ago would be your best bet, if you can find one. One you find fitted to an old car in a scrapyard is probably also good - it's unlikely the car was scrapped because it had a faulty coil. If your coil is working well and you don't have a spare, get hold of a second one and swap them over. Then keep the known-good one in the boot in case the new one fails. Hopefully the new one will prove itself and then you'll have two known-good coils.

[bmcecosse]

Same policy with fuel pump and alternator works well!

[dellerie]

christ, with the amount of spares you lot carry around, you must all hitch a trailer up!

[LouiseM]

I used to have a known good coil in the boot a few years ago but it was stolen along with the bag of tools it was kept in. I thought at the time it was an opportunist theft but perhaps the coil was stolen to order!

[chrisryder]

i keep a known to be good coil in my boot (i should be carefull about saying that, maybe mine will be hit too!) as i took the previous one off not as it was dodgy, merely to fit a 'sports' one to compliment my fresh engine, electronic ignition, and new plugs. so that is one way of having a good coil in the boot!

[moggyadventurer]

Can someone explain the difference between a standard and sports coil and potential benefits?

Cheers

[chrisryder]

i think the basic idea is that a sports one give a juicier spark. but a good coil is nothing without means of getting it to the plug. so electronic ignition and silicone leads and good plugs are a worthwhile combination with a sports coil. i'm not sure of the benefits with using a sports coil on a standard setup, whether there is no advantage or just less advantage... someone more knowledgable will be along in a minute i'm sure!

[bmcecosse]

If it says 'Sports' on it then a) they can charge more for it and b) the car will go MUCH MUCH better - obviously.......
The size of the spark depends to an extent on how long the coil gets to 'charge up' between sparks - so a tiny points gap gives max time with points closed and charge building up. Problem is the tiny gap will very easily reduce to nothing - with obvious engine death. So the suggested 15 thou gap is a bit of a compromise. Run less if you want a bigger spark! But I would certainly be interested to know the resistance of the LV side of a 'Sports' coil - a standard 12 volt (actually runs at 14 v) coil is 3.2 ohms.
However - for a normal engine running 25 thou gap plugs - the standard coil gives a perfectly adequate spark to ignite the fuel - and opening up the gap (possibly needing higher volts) really doesn't make the engine run any better.

[Alec]

Hello BMCE,

"and opening up the gap (possibly needing higher volts)"

that is the point, a higher voltage than needed doesn't gain anything, but worn plugs or a tuned engine (Higher compression pressure) requires a higher voltage so a sports coil may be benefitial in those circumstances? It does put more stress on the leads, cap and rotor however.

Alec