Spark Plug
#17
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Year: 1990
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#18
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Year: 1999
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I don't think NGK makes an Iridium plug for the 1990 4.0.
Click the Application Search tab at the top.
http://www.ngkiridium.com/shop/category.asp?catid=8
Champion has one. Part number 9001
#19
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Honestly, I probably just like to wrench but I put in standard Champion Coppers and change them out every 20 to 30k miles (once a year for me).
Takes around 30 minutest to swap them all out for me, but I have the perfect wobble joint for the plug that's furthest back which makes it super easy.
I also wire wheel and polish the distributor cap + rotor because I am too cheap to get a new one but it seems to be working just fine.
Takes around 30 minutest to swap them all out for me, but I have the perfect wobble joint for the plug that's furthest back which makes it super easy.
I also wire wheel and polish the distributor cap + rotor because I am too cheap to get a new one but it seems to be working just fine.
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#21
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Year: 1990
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Honestly, I probably just like to wrench but I put in standard Champion Coppers and change them out every 20 to 30k miles (once a year for me).
Takes around 30 minutest to swap them all out for me, but I have the perfect wobble joint for the plug that's furthest back which makes it super easy.
I also wire wheel and polish the distributor cap + rotor because I am too cheap to get a new one but it seems to be working just fine.
Takes around 30 minutest to swap them all out for me, but I have the perfect wobble joint for the plug that's furthest back which makes it super easy.
I also wire wheel and polish the distributor cap + rotor because I am too cheap to get a new one but it seems to be working just fine.
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#23
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Year: 1990
Model: Cherokee
Engine: 4.0L
Generally Iridium spark plugs are recommended for use in waste spark ignition systems, like the '00/'01 4,0.
Here's a spark plug application chart. These are all copper/double copper plugs.
For the '90 4.0 you may want to try the NGK FR5 plugs. Note the Champion heat range of "9". You want to stay in that heat range for the '90 4.0
Edit: I'm sorry if I offend, but I think using Iridium plugs in a non-waste spark engine is like putting lipstick on a pig.
Here's a spark plug application chart. These are all copper/double copper plugs.
For the '90 4.0 you may want to try the NGK FR5 plugs. Note the Champion heat range of "9". You want to stay in that heat range for the '90 4.0
Edit: I'm sorry if I offend, but I think using Iridium plugs in a non-waste spark engine is like putting lipstick on a pig.
#24
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Year: 1990
Model: Cherokee
Engine: 4.0L
Use the Champion coppers gapped to 0.035" especially if your ignition system is original. I have an MSD coil, Magnecore wires and upgraded battery cables, so I'm using Autolite iridium plugs gapped to 0.050". This works for me only because of all the other upgrades. My choice to use iridium was solely to see if the small electrode would further enhance flame kernel generation in combination with the increased gap. The bottom line is that they're working perfectly, but I'll probably go back to copper if I ever need plugs again--the small iridium electrode hasn't made a significant impact, and copper is a better conductor.
With a stock system, cap and rotor with brass contacts, Champion coppers, and Belden wires from NAPA are my choice and recommendation.
With a stock system, cap and rotor with brass contacts, Champion coppers, and Belden wires from NAPA are my choice and recommendation.
#25
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Your choice but I think you should stick with Champions and inspect/change them about every 20,000 miles.
Kit? Don't forget cap and rotor. I recommend Echlin parts from NAPA. Cap and rotor should be a matched set.
#27
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I'm well researched, experienced, and don't just do things *****-nilly. I know my ignition system doesn't manufacture rainbows while curing cancer, but as a system and in conjunction with the rest of my mods/build, I'm getting what I hope to out of it. The iridium is actually the least beneficial part, and if they ever crap out, I'm going back to copper but keeping the 0.050" gap. My MSD coil and Magnecore 8.5 mm wires are doing just fine, thank-you.
Last edited by mschi772; 05-29-2015 at 05:47 PM.
#28
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Year: 1999
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I'm well researched, experienced, and don't just do things *****-nilly. I know my ignition system doesn't manufacture rainbows while curing cancer, but as a system and in conjunction with the rest of my mods/build, I'm getting what I hope to out of it. The iridium is actually the least beneficial part, and if they ever crap out, I'm going back to copper but keeping the 0.050" gap. My MSD coil and Magnecore 8.5 mm wires are doing just fine, thank-you.
Lipstick, powder, and paint, makes a lady what she ain't.
#29
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Generally Iridium spark plugs are recommended for use in waste spark ignition systems, like the '00/'01 4,0.
Here's a spark plug application chart. These are all copper/double copper plugs.
For the '90 4.0 you may want to try the NGK FR5 plugs. Note the Champion heat range of "9". You want to stay in that heat range for the '90 4.0
Edit: I'm sorry if I offend, but I think using Iridium plugs in a non-waste spark engine is like putting lipstick on a pig.
Here's a spark plug application chart. These are all copper/double copper plugs.
For the '90 4.0 you may want to try the NGK FR5 plugs. Note the Champion heat range of "9". You want to stay in that heat range for the '90 4.0
Edit: I'm sorry if I offend, but I think using Iridium plugs in a non-waste spark engine is like putting lipstick on a pig.