Instant cure for engine malfunctions

[Nick Salmon]

Reading Tony's thread about a sudden change in the way an engine runs, I thought I would share this in case it helps others...

Over the last two or three years, several of my cars after standing unused for many weeks in dry storage have exhibited a reluctance or downright refusal to run. In all but the latest case they were running fine when put away. 

In all cases, a change of spark plugs effected an immediate cure.

In the latest episode, my MG VA suddenly ran rough as I was putting it into storage last November. Not having time to deal with it there and then, it was only last week that I got around to seeking what the problem was. Despite fully charged battery, fresh fuel, spark at the points and a decent spark on a removed plug, and applications of Easy Start, it refused to fire or run. I checked the SUs jets etc, all seemed fine. 

I was scratching my head when I remembered there was a spare set of new plugs in the boot. Fitted them and the engine instantly fired and ran smoothly. 

The removed plugs are standard, so I would expect zero resistance between top and electrode tip. Three showed no resistance, the fourth did. Whether this has any bearing on the refusal to fire at all, I do not know. Seems unlikely, but the ways of electrickery are mysterious.

As I say, having had this sort of thing now happen on several different vehicles and for a change of plugs to be the instant cure for non-start/rough running I cannot believe it is just coincidence. Maybe ethanol is at the root? Perhaps leaving a coating on the plugs if they are not used for a while?

Point of this is to say that from now on, unless something else is obvious, when an engine decides not to perform in some way, I shall always change the plugs first. Just to cover off that possibility.

I half-joked with friends that it might be that mainstream brands are manufacturing in China, with a possible reduction in quality. And then yesterday a replacement set of Bosch plugs arrived. Guess what...


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[Tony Griffiths]

Once the engine is running and hot, how about removing one of the new plus and replacing it with an original to see what would happen?
I recall, decades ago, just for fun, building up a set of plugs with mica insulators and 'dismountable bodies'. The set of four was an assembly of parts and of the three-electrode type - and all in a really bad way. To my astonishment, the car started and ran on them perfectly.

[Chris KC]

"Easy Start" is basically pre-ignition in a can. I wonder if it could be killing your spark plugs?

[Dave Mann]

It's some years ago I stopped buying Chinese products like the £2.00 bush saw blade which was useless, I found a traditional engineers tool store which still produces hand written receipts sold a Bahco blade for £9.00 which was like a hot knife through butter. Buy cheap Chinese at your risk.

[A G Wood]

Reduction in quality used to happen with OE Champions too, back in the pre-PRC manufacturing days on some of our stuff.
The taper seat ones that went in the V8 Clevelands used to randomly short out under acceleration up inside the shell where the seal compound between the insulator nose and the metal body was, which meant no spark at the actual gap. 
It was good insurance against an angry owner to 'proof test' the brand new set you were going to fit, using the pressurised chamber and HT buzzer on the workshop spark plug machine. Not strictly a real world test, but anything that showed the slightest sign of activity outside the official spark zone was certain to cause a misfire in the engine.

[Nick Salmon]

Chris - I only use Easy Start in the circumstances outlined. Never otherwise.

Tony - I will try putting the plug back that shows resistance and see what happens.

[Nick Turley]

Fascinating stuff, I would suspect damp air, providing water on the ethanol deposit left on the plug.
Suggestion :
As a lay up comparison try putting Millers "Tank safe " in the fuel tank and let it run through the system before leaving the car for the winter.
It is what I do.
Cars seem to start after layup OK.
The bonus is the petrol does not go off and the tank does not corrode.
Worth a try.

[Old Dave]

Dave Mann said  " It's some years ago I stopped buying Chinese products like the £2.00 bush saw blade which was useless, I found a traditional engineers tool store which still produces hand written receipts sold a Bahco blade for £9.00 which was like a hot knife through butter. Buy cheap Chinese at your risk."

I remember your article in the Comic a while back Dave - very true. Qualiity stuff of the past, now made in China is often sub-standard now.

[stuartu]

Some 20 or so years ago I recall asking a German acquaintance who worked for a major engineering firm in his native land, “Do you have any of your castings made in China?” He replied, “Only the ones that don’t matter”.

Regards,

Stuart