When to change spark plug wires?

Seems logical, how many are there? 30k sounds expensive.

 

I would highly suggest staying away for platinum and iridium plugs for the 4.0 engine. Silver is the best conductive metal. I’ve seen a chart years ago that I can’t find now that shows silver as a 100 on a scale of 0-100. Copper was 97 platinum was something like 60 and iridium was maybe 55. Feel free to site a more accurate number if you find it. There are racing plugs made with silver but they only have to last for a few hundred miles. Copper is barely behind silver.

Assuming I’m in the ballpark you can see that it would take a much higher voltage to jump the gap and create a spark. Your 4.0 was built for copper plug voltages and iridium could cause misfires.

Also copper runs so much cooler than metals of the platinum class (iridium included). Engineers planned for the heat dissipation of copper and not platinum. Platinum type plugs will run hotter than designed.

Stay with copper to get the performance the engineers designed. It’s better to run perfect for 30K miles and change them than chasing codes and issues for 100K miles.

Everyone’s entitled to my opinion. Feel free to express yours.

 

Dealer purchased copper are cheap plugs. I’ve changed mine 5 times and it’s really a piece of cake. I can do it carefully with torque wrenches in about an hour. First time was maybe 2 hours.

 

Supposedly the iridium plugs in my 4Runner are good for 120k

 

Speaking of wires, I bought my first car when I was 15. ‘68 Mustang w a 302, distributor cap right in front. Did the whole tune up thing including wires, started ‘er up and it was running a bit rough. With it still running, I put my hand on top of the distributor cap and pushed down hard - thinking the wires weren’t seated fully. The hand and arm went numb for about an hour…

That car was a great learning experience..

Back to original programming.

 

Oh yeah, been nailed a few times by a plug wire working on my old '65 Nova back in the day.

 

I was working on this antique today and had to change distributor cap

 

Right of passage for us old farts.

 

Well not to stick up for OP, but his answer was posted 3 minutes after asking. So he had 8 minutes to think about it per your time line.

 

Remember the old Tom Boy push mowers? They had a cast aluminum deck and were pretty heavy. When I was a kid, I was having trouble starting ours. I finally stood up on the mower, straddling the engine and gave a mighty pull of the cord. My bare ankle was against the end of the spark plug.
THAT was a shocker.

 

I change my spark plug wires when I change my blinker fluid.

 

Dealer says the plugs are zinc coated, I don’t see that recommendation anywhere here. The guy said I’d have to go get them stripped and coated myself if I want copper or platinum.

Looked like this

 

Do you really think Toyota makes spark plugs? Tacos literally roll off the assembly line with NGK in one bank and Denso in the other.
Well, technically Toyota is a shareholder (or at least was) in both companies.

 

Mid 50’s = old fart? Guess I need to start acknowledging reality

 

One of the old timers I worked with used this method to test how strong the spark is.

 

I wish. Mid-60s here.

 

No.

 

When I changed my plugs the last time I went back to copper and also changed these parts. OEM from RockAuto.

 

I hope you are being sarcastic.

That is a freeze plug in the block....

 

Sometimes we need to be a little sarcastic, plus it keeps these threads spicy