Ignition leads cautionary tale

[FordnMassey]

Hi,

Thought I'd share an experience of mine that occurred while working on my Massey Ferguson 35. When trying to resolve a misfire, I replaced the spark plug leads with a new set as shown on the right of the photo, thinking I was improving the ignition system. At 1 year old, they were arcing thru the rubber ends to anything close by.

Not everything new is better.

I have since bought a set as shown on the left, which have hard plastic spark plug ends and are apparently superior. Time will tell.

 

[rScotty]

The best spark plug wires have three insulation coatings and a stranded copper wire that is soldered to the ends caps. Hotrodders and racers have known that they have to make them right that way for years.

But even those parts are hard to come by. When I went to automotive stores - includng NAPA - last year I found they didn't even carry the parts to make up spark plug wires from scratch.

It's such an easy thing to do, and makes such a large difference in performance.
rScotty

 

[Williy]

The best way to find a miss (bad plug wire)
is at night when its dark easy to see the
sparks fly

willy

 

[FordnMassey]

The best way to find a miss (bad plug wire)
is at night when its dark easy to see the
sparks fly

willy

Yep, that's how I accidentally found they were arcing. Otherwise I would not have considered the leads as possibly bad, given how new they were.

 

[metalbender]

Spray a little water while it's running, darkness helps.
Years ago a buddy bought high perf wires for his 70 Hemi Cuda, same wires as the old 354 Hemi used in 1954. Ceramic ends down the tubes.

 

[FordnMassey]

And in breaking news, here's a photo of the distributor cap. Again, 1 year old. That centre post has snapped away or was destroyed by arcing sparks.
I've installed the old one, which I luckily had put aside.
New may not be better.

 

[Oaktree]

But even those parts are hard to come by. When I went to automotive stores - includng NAPA - last year I found they didn't even carry the parts to make up spark plug wires from scratch.

Coil pack ignition systems have been around now for what, 35 years? Way longer than that since tractors had gasoline engines. Can't imagine there's much demand for the old school plug wires anymore. I'm sure what you're looking for can be special ordered or found online.

 

[Norm W]

Ignition wires for boilers are copper wire and well insulated. Unfortunately, they come on a rather large spool. If you have a friend, or can reach somebody, that does boilers they may be able to get you some. The ends (boots) may still be a problem.

 

[DJ54]

NAPA has Belden 7mm copper core wire with silicone jacket sets complete with ends/boots, you just need to cut to size, put distributor boots & ends on. They show 2 different types, not sure what the difference is. https://www.napaonline.com/en/p/BEL700169?impressionRank=1 They used to carry 4 cyl., and 6 cyl. sets, but just the 6 cyl. sets now.

I bought 2 different rolls of Belden 7mm wire at auctions years ago cheap, both probably 75% full of 100' rolls. Still using off one of the rolls and have made numerous sets, and single wires for antique garden tractors. Used up all of my ends boots 2 years ago, and went to NAPA for both, and different end style boots. Had to order them in from the warehouse, but fortunate enough got them the next day.

They also still carry 100' bulk rolls of the 7mm copper core wire, but pretty pricey now a days. Rock Auto also carry's bulk wire. Being I have 20+ tractors, those bulk rolls I bought years ago have well paid for themselves. If you have just a few tractors that need wires replaced, the above sets would probably be the way to go.

 

[Williy]

Years ago I had a small Dodge pickup
and it was missing really bad took it to
the Dodge garage only had it 6 months
so though that it was under warranty
but no they said the plug wires were not
covered after 1 1/2 hours the mech could
not find the problem the inside of the
distributor was burned up! I replaced the
plug wires solved the problem way too
much resistance on the plug wires and
the juice couldn't exit so burned up the
distributor.

willy