Absolute best lead/sock/extender solution?
Discussion
Of course nothing is indestructible, and while we all like to talk about the effects of exhaust manifold heat on our HT leads there is actually a lot more to consider. Even with good quality MSD boots this is what can happen when burning hard to ignite LPG in the combustion chamber using a very powerful ignition system.... and resistance at the spark plug goes through the roof!
This situation is not unique to LPG, keep in mind your spark is always going to find the easiest path to ground, and in certain circumstances (poor grounding and or wet/humid conditions) this path might not be your spark plug's ground electrode
I've seen situations where my spark will blow a hole clean through 3mm of high temp silicone
Powerful stuff
In this case removing the spark plug revealed it to be loose, frequent plug removal for inspection demands the spark plug crush washer is replaced with new as like any crushable type sealing washer they are a 'one time fit' deal.
Analysing the situation a little closer and we can clearly see hot combustion gasses had passed up the plug carbonising the anti-seize grease on the plug threads causing a poor ground.
Zooming in on the sectioned plug boot the autopsy shows us the energy has found its way as far as sharp edge of the spark plug terminal inside the boot.
From here a spark was formed punching its way clean through 3mm of high temp silicone to find it's way to the cylinder head where the ground path was better than the plug ground electrode that should be (but wasn't) well grounded to the head through the plug thread.
This sort of thing....
Its why for years NGK and others have electroplated their plug threads for corrosion protection and advise against the use of any type anti-seize grease (Copperslip ect), even when the plug is being fitted in an aluminum cylinder head! Of course it doesn't matter what the makers of these greases say.... no grease is a conductor!
All greases are insulating agents which is the last thing you want to put on something that relys on a good ground connection
Use quality plugs with electroplated threads, properly torque them in the head and change them regularly and if you do inspect them mid service life always replace the crushable washer on each plug when refitting. These are the essential rules to avoid issues, and completely removes the need for insulating anti-seize grease which only serves to interfere with the very ground path that's so essential for good spark plug performance and high tension ignition reliability.
Remember electricity will always find the easiest path to ground, the well discussed heat protection subject aside the way to ensure your HT leads have a longer life is to do everything you can to make your spark plug ground electrode that easier path to ground. The car will suffer less misfires so will drive better too, clearly good plug to head contact is critical as is the quality of your engine grounding
This situation is not unique to LPG, keep in mind your spark is always going to find the easiest path to ground, and in certain circumstances (poor grounding and or wet/humid conditions) this path might not be your spark plug's ground electrode
I've seen situations where my spark will blow a hole clean through 3mm of high temp silicone
Powerful stuff
In this case removing the spark plug revealed it to be loose, frequent plug removal for inspection demands the spark plug crush washer is replaced with new as like any crushable type sealing washer they are a 'one time fit' deal.
Analysing the situation a little closer and we can clearly see hot combustion gasses had passed up the plug carbonising the anti-seize grease on the plug threads causing a poor ground.
Zooming in on the sectioned plug boot the autopsy shows us the energy has found its way as far as sharp edge of the spark plug terminal inside the boot.
From here a spark was formed punching its way clean through 3mm of high temp silicone to find it's way to the cylinder head where the ground path was better than the plug ground electrode that should be (but wasn't) well grounded to the head through the plug thread.
This sort of thing....
Its why for years NGK and others have electroplated their plug threads for corrosion protection and advise against the use of any type anti-seize grease (Copperslip ect), even when the plug is being fitted in an aluminum cylinder head! Of course it doesn't matter what the makers of these greases say.... no grease is a conductor!
All greases are insulating agents which is the last thing you want to put on something that relys on a good ground connection
Use quality plugs with electroplated threads, properly torque them in the head and change them regularly and if you do inspect them mid service life always replace the crushable washer on each plug when refitting. These are the essential rules to avoid issues, and completely removes the need for insulating anti-seize grease which only serves to interfere with the very ground path that's so essential for good spark plug performance and high tension ignition reliability.
Remember electricity will always find the easiest path to ground, the well discussed heat protection subject aside the way to ensure your HT leads have a longer life is to do everything you can to make your spark plug ground electrode that easier path to ground. The car will suffer less misfires so will drive better too, clearly good plug to head contact is critical as is the quality of your engine grounding
Please read Dave I was fitting plugs way before you was installing them in old cast iron s
t , alloy heads = anti-seize , applied little like pic https://www.hondapartsonline.net/blog/how-to-chang...
t , alloy heads = anti-seize , applied little like pic https://www.hondapartsonline.net/blog/how-to-chang...
Thanks for that Simon, as you know I always bow to your superior knowledge.
I think the problem here is the worlds largest and most respected spark plug manufacturer have got it all wrong.
https://ngksparkplugs.com/en/resources/5-things-yo...
In NGKs above 'Five Things You Should Know About Spark Plugs' communication they put not using anti-seize as number one on the list, presumably because if you're going to make such a glaring gaff you may as well get it out of the way first.
Obviously the point regarding observing the torque setting communicated by NGK and set out by the car maker themselves is irrelevant for super master time served mechanics with huge experience in fitting spark plugs, but I don't think my post or the advice from NGK is intended exclusively for these 'Spanner Yodas' who have spent years developing their black belt torque wrench fingers.
Despite NGK's stupid mistake and incorrect advice my point about anti-seize grease (no matter what type) being non conductive still stands, we can all test this for ourselves by getting a blob of copper slip and measuring it's resistance
I hope others found my post interesting and well presented, it is after all using images of real example parts as supporting evidence, parts that were fitted to a real Chimaera and failed as shown. The important point here is the spark blow through I've shown had absolutely nothing to do with heat damage, which if you read these pages regularly will have you believing this is the only reason HT leads fail on our cars.
I think the problem here is the worlds largest and most respected spark plug manufacturer have got it all wrong.
https://ngksparkplugs.com/en/resources/5-things-yo...
In NGKs above 'Five Things You Should Know About Spark Plugs' communication they put not using anti-seize as number one on the list, presumably because if you're going to make such a glaring gaff you may as well get it out of the way first.
Obviously the point regarding observing the torque setting communicated by NGK and set out by the car maker themselves is irrelevant for super master time served mechanics with huge experience in fitting spark plugs, but I don't think my post or the advice from NGK is intended exclusively for these 'Spanner Yodas' who have spent years developing their black belt torque wrench fingers.
Despite NGK's stupid mistake and incorrect advice my point about anti-seize grease (no matter what type) being non conductive still stands, we can all test this for ourselves by getting a blob of copper slip and measuring it's resistance
I hope others found my post interesting and well presented, it is after all using images of real example parts as supporting evidence, parts that were fitted to a real Chimaera and failed as shown. The important point here is the spark blow through I've shown had absolutely nothing to do with heat damage, which if you read these pages regularly will have you believing this is the only reason HT leads fail on our cars.
Dave look at the pic above no mention of globs or blobs of copper grease, Denso plugs for LPG powered forklift trucks come pre lubed with ,.......................... Yeh anti-seize paste , I don't know better than NGK but I know what works in the real world on used vehicles not brand new factory engines running in a test cell
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