HT Output.

[Mike J]

Is there a relatively easy way to check the actual out put from the HT leads. Is there something like a multimetre that could give a reading. I feel there is some variation. I'm getting a spark but the engine still isn't running smoothly. Mike

[V Mad]

You could check the resitance of the leads, and compare them; if they all all the same then its OK. This is not usally the problem with HT though. Mains HT problems are tracking (HT leaking away somewhere), faulty plug, or fault in the dissy. Do you have a points dissy?

[jakesmig]

No use to you, but there was a bloke at school with me who could hold an HT lead without flinching and wouldtell you if it was a good output. Normally did it on m'bike engines with magnetos.
Normal type for a prop forward, felt no pain, had no brains.

[Mike J]

You could check the resitance of the leads, and compare them; if they all all the same then its OK. This is not usally the problem with HT though. Mains HT problems are tracking (HT leaking away somewhere), faulty plug, or fault in the dissy. Do you have a points dissy?

Brilliant idea. Will check the resistance. Should I be putting anything on the ends of the HT leads to improve connection wd40 or something. If they are about 10mm apart that should be enough do you think. I have Luminition optical Ignition. Mike.

[V Mad]

No you dont need WD40, just good leads. There has benn quite a few failures of Lumenitions, so that's a possible suspect too.

[Mike J]

Sounds like my sort of luck. Any way of checking the output from the Luminition unit? Or do I go back to points to see if that makes any difference. Mike

[Stagdad]

How about one of these

http://www.ebay.co.uk/itm/VS5271-BRAND-NEW-SEALEY-AUTOMOTIVE-HT-LEADS-SPARK-CHECK-TESTER-KIT-/260912502422?pt=LH_DefaultDomain_3&hash=bin3cbf98d696

Looks like you can widen the gap in the tester until the spark fails.

Cheers Steve

[wilf]

That's the way - checking the distance the spark will jump is the only way to assess HT voltage - you can't measure it with any reasonably easily available meter.

[martin]

Hi Mike, I hate to say this, but you may have valve issues, are there any noises associated with the problem, i.e. ticking ? Martin.

[V Mad]

Sounds like my sort of luck. Any way of checking the output from the Luminition unit? Or do I go back to points to see if that makes any difference. Mike

Substitution yes, thats probably the best way.

[Duncan Skye]

There is an article in the March 2012 issue of Practical Classics on how to measure the resistance of your HT ignition leads. Page 77.

Duncan, Skye

[Mike J]

Thanks every one I have ordered one of those test units from ebay.(13.00 ish) I presume you retract the one end until you don't get a spark and compare the results. Looking forward to this experiment. I noticed in their other products they had a device that sits between the end of the HT and the plug. If you bought 2 sets 8 for about a tenner you could see if there were misfires on any particular cylinders.
I hope there are one or two dodgy HT leads on my car. Otherwise I'll be hastling you all again. The plugs all look the same when out and are all getting a spark.