Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Spark Plug Leads falling off!

A good drive followed by failure just minutes from home. The lead to the right cylinder fell off the plug and naturally that cylinder quit firing. These plugs are the Iridium line and have a screw on nipple. Like other plugs the damn nipple works its way off.

Solutions?

Loctite and a screw on clamp? Better leads that really hold on? Prayer?

Unless you're dedicated to those plugs, why not ones that have an integral nipple instead of screw on.

Otherwise hold the plug with a wrench and tweak down the nipple with some pliers.

Been There Done That. Problem is that when you are able to tighten it down it is cold. Then it gets hot. Then cold. Add vibration. This goes for the rest of the car as well. I regularly schedule time to just tighten stuff down as it is a race to keep stuff from falling off!

I can't imagine loctite would totally insulate things, I know it's an insulator but there would still be plenty of metal on metal contact. Blue is good for 300 degrees red 450. But I'd probably go with some plugs that didn't have the screw on end if that's the case.

I've not have any issues like that on any of my bikes or scooters, but then again none have had an engine as big as on the Morgan, and I don't know that I ever ran plugs with a screw on nipple.

Thanks for the reminder Michael! I move the car between Los Angeles and Phoenix summer and winter and am headed back to LA this Friday. I just checked and they were finger tight. Snugged them with the pliers.
I don't know of a good ultimate solution, maybe mix up a bit of JB Weld and dab a tiny dot of it (using a toothpick) on the screw on end. That should lock the two bits together. Let it dry before putting the lead back on....

I just installed NGK DCPR7E spark plugs ( integral nipples or really tight since I couldn't unscrew them ) because my Autolites with screwed on nipples kept loosening up as well. If I remember correctly Harley Davidson equivalent spark plugs may also have integral or really tight nipples.

One mechanic I knew used channel lock pliers to squeeze the nipples to make them out of round so they tended not to loosen.

In the old days plug leads finished with an eyelet and the head of the plug unscrewed so that the eyelet could be fixed to the plug, making it impossible for it co come off.

Then "snap on" plug caps appeared. Never been a great means of establishing a secure HT connection, in my view.

A dab of thread lock on the lowest coil of the thread could be tried, or carefully oval the cap in a vice (for control) by a smidgeon!

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