Replacement Plug Wires

[FredG]

Gentleman,

The Roush 427r was built and installed in my Backdraft in 2013. Ignition is MSD6AL. Car has less than 3k miles but I am reading that hi-performance plug wires have a life expectancy of 5-6 years but is mileage the better determiner for replacement. This was news to me. If this is correct, what are some options for Hi-Perf. replacements. MSD 8.5 mm Super Conductor wires are mentioned often. Any other recommendations. Thanks

Fred

[ront49]

My Backdraft had about 4k miles when I purchased it...I have never found out who built the engine, a 418 stroker but it had Ford Racing plug wires, 8.5 on it. They looked like a snake that swallowed twenty chicken eggs. Too much heat and too close to the headers. They also had aluminum heat shields on the plugs which I removed...I replaced the wires with Ford Racing 8.5 wires from summit.
Have about 6k on the car now and so far no heat or distortion of the wires. I check them constantly and figure I'll have to replace them in a few thousand miles...I'm sure Summit will have some suggestions for replacements. Those guys know their business and are excellent to work with.

[ront49]

I failed to mention that the car ws Build No. 151, built in 2004 so the wires had been on there for quite some time....that should not make a difference on longevity...

[Mike I]

Fred,

If rubber is pliant and no obvious signs of damage due to heat or abrasion, just do a resistance check on each wire with a VOM. If all wires test within range, no reason not to continue using them.

FWIW, I have MSD 8.5 MM wires on my car at least ten years old with no issues.

[bobcowan]

Plug wires are a replacement item, just like the plugs. When they start to go, they leak electricity through the insulation. When they get really bad, you can see a blue haze near the wires when the engine is running in the dark.

A good set of plug wires is pretty cheap, around $100. If they're old, I can't think of a good reason NOT to replace them. One my race car, I replace them every 2-3 seasons just as preventative maintenance.

[Mike I]

You'll notice reduced performance long before you start seeing St Elmo's fire...either way, wires are likely shot at that point and won't meet the resistance spec, so...

Another thing, a good quality set of wires won't arbitrarily go bad simply by transmitting electrons they're designed to transmit. Something has to intervene to cause resistance to increase, such as excessively high heat, abrasion, pulling on the wire instead of the boot to remove from plugs, etc. If none of those conditions are met and the resistance is in range, what's to be gained by replacing them?

Me personally, I don't replace them unless I suspect they've gotten damaged and are no longer performing as they should, however, nothing wrong with replacing them as a time compliance item as Bob recommends.

[tortuga]

Buy a Tool that enables you to make your own ends, then buy a "Universal" plug wire set. Doing plug wires is sort of a fun project, one of the few tasks where you can personalize your engine room...Also nice not to have too long wires dangling all over the place.

[Gaz64]

Originally Posted by tortuga

Buy a Tool that enables you to make your own ends, then buy a "Universal" plug wire set. Doing plug wires is sort of a fun project, one of the few tasks where you can personalize your engine room...Also nice not to have too long wires dangling all over the place.

+10.

A well routed plug wire set makes an engine bay.

Leads too long, routed incorrectly etc, just ugly.

I have made my own a few times.

I love pulling my valve covers without pulling a lead off.

[Unique427]

Originally Posted by Mike I

Fred,

If rubber is pliant and no obvious signs of damage due to heat or abrasion, just do a resistance check on each wire with a VOM. If all wires test within range, no reason not to continue using them.

FWIW, I have MSD 8.5 MM wires on my car at least ten years old with no issues.

For MSD 8.5mm, resistance test should show 40-50 Ohms/Ft.

[Karl Bebout]

Definitely get a universal set so you can make things prudy. I prefer Taylor wires primarily because the clips on the spark plugs are better, in my opinion.
Also, save headaches down the road by liberal use of dielectric grease on the inside of the boots on both ends. Don't get it on the contacts. QTips do a nice job applying the goo. My 2¢