Manufacturing new high tension leads

[Ron B.]

As my 14 is approaching 10 years old, it’s time to replace my spark plug leads for my Lightspeed ignition. My unit came with MSD leads and I’m replacing with the same. I purchased the MSD crimping pliers. With my first attempt I cannot get an ohm reading on the one that I making. Testing the original, I get 68 ohms which sounds about right as it is 19” long. I think I have a problem with the first crimp , crimping down on the small interior wire. I’ve watched videos but still cannot see what I’ve done wrong. Looking for guidance.
Thanks Ron

 

[bjdecker]

Personally, I wouldn't have undertaken the effort unless the resistance of the wires had risen above (or fallen below) the typical Ohms-Per-Foot measurement (~40-50 Ohms/ft), and/or the terminal ends weren't tight on the plug or coil terminals.

The MSD video is good, but it's hard to see where the black center conductor sits. The black center conductor should get trapped/squeezed/crunched between the two lugs at the front of the terminal. The remaining tangs go over/around the insulation. Don't forget to put the boots on first

 

[Ron B.]

Personally, I wouldn't have undertaken the effort unless the resistance of the wires had risen above (or fallen below) the typical Ohms-Per-Foot measurement (~40-50 Ohms/ft), and/or the terminal ends weren't tight on the plug or coil terminals.

The MSD video is good, but it's hard to see where the black center conductor sits. The black center conductor should get trapped/squeezed/crunched between the two lugs at the front of the terminal. The remaining tangs go over/around the insulation. Don't forget to put the boots on first

Didn’t know I had to? Seems they would go on much easier after. I have a nic in one that started the process.
I will have to seek more help in defining the process.
Thanks

 

[jherzog]

I think I have a problem with the first crimp , crimping down on the small interior wire. I’ve watched videos but still cannot see what I’ve done wrong. Looking for guidance.
Thanks Ron

I made a set last year. Not sure what videos you've seen but Vic Syracuse has a nice one:

.

A couple of things:
1. I think its best to have the bare wire extending slightly into the cylindrical portion of the connector (that clamps around the spark plug).
2. When doing the first crimp, I found its best to angle the bare wire slightly downwards, towards the bottom of the cylindrical portion of the connector.

Jordan

 

[Ron B.]

I made a set last year. Not sure what videos you've seen but Vic Syracuse has a nice one:

.

A couple of things:
1. I think its best to have the bare wire extending slightly into the cylindrical portion of the connector (that clamps around the spark plug).
2. When doing the first crimp, I found its best to angle the bare wire slightly downwards, towards the bottom of the cylindrical portion of the connector.

Jordan

Thanks , much better video than the ones I watched.

 

[Ron B.]

Gaining, I tried another lead. The old one has a resistance of 53 ohms. This one is about a foot long so I think that’s what one would expect. But the new one , using the exact same cable ( new but I bought it maybe 8 years ago) reads 65 ohms. Same length. Is this something that might take place and acceptable?
Thanks Ron

 

[jackking123]

I remember as a hot rod'er teenager a few years ago rolleyes: many decades) I made high tension ignition leads, like MSD. I always found those crimps challenging. I don't think there is anything wrong per se proactively replacing spark plug wires. For me visual inspection and engine running normal is goodness.

As far a ohm reading read up on that. A typical multi-meter draws a very small current, typically in the range of microamps (µA) and voltage is usually very low, often in the millivolt range, for resistance reading. In operation you are pulsing 20kV or double that. I'm not up on how to TEST these wires. In car world it was just replace them proactively unless they had physical damage or failed completely. I have a diesel car and an EV now. My motorcycle has spark plug coil packs on the plug. So no plug wires to deal with on my earth bound vehicles.

However, the spark plug wires can wear out and breakdown over time, which can lead to misfires and loss of power. Looking at the car world, consciences is around 60,000 miles, say 6 years. Then I read from the WWW even "lifetime" plug wires will begin to have the insulation fail after 30-40,000 miles, or 2-4 years? Of course most modern car engines have no plug wires, they have individual coil packs on each plug, and sometimes very short high tension leads. On the other hands people that do use sparkplug wires drive with same plug wires for the life of the car.

I'd say aircraft have more heat and vibration than a car, but aircraft accrue also less hours. So how many hours in 10 years?

 

[Ron B.]

I remember as a hot rod'er teenager a few years ago rolleyes: many decades) I made high tension ignition leads, like MSD. I always found those crimps challenging. I don't think there is anything wrong per se proactively replacing spark plug wires. For me visual inspection and engine running normal is goodness.

As far a ohm reading read up on that. A typical multi-meter draws a very small current, typically in the range of microamps (µA) and voltage is usually very low, often in the millivolt range, for resistance reading. In operation you are pulsing 20kV or double that. I'm not up on how to TEST these wires. In car world it was just replace them proactively unless they had physical damage or failed completely. I have a diesel car and an EV now. My motorcycle has spark plug coil packs on the plug. So no plug wires to deal with on my earth bound vehicles.

However, the spark plug wires can wear out and breakdown over time, which can lead to misfires and loss of power. Looking at the car world, consciences is around 60,000 miles, say 6 years. Then I read from the WWW even "lifetime" plug wires will begin to have the insulation fail after 30-40,000 miles, or 2-4 years? Of course most modern car engines have no plug wires, they have individual coil packs on each plug, and sometimes very short high tension leads. On the other hands people that do use sparkplug wires drive with same plug wires for the life of the car.

I'd say aircraft have more heat and vibration than a car, but aircraft accrue also less hours. So how many hours in 10 years?

I have around 350hrs on mine.