Spark Plug Replacement…

New to YJ Jeeps · May 23, 2024

Hey guys, I went to replace my spark plugs yesterday and after I pulled the first spark plug out I thought that I should probably look up how to do it lol. I’m glad I did because I had no clue about spark plug gapping and using dielectric grease as I’ve never replaced spark plugs before. I also had the wrong spark plugs so I made a last minute run to autozone to pick up what I needed. Today I gapped all the new spark plugs to .035 inches as the manual says to, I pulled out the old ones, put some dielectric grease on the new ones (as well as the inside of the spark plug wires) and put em back in then tightened them somewhere in between 26-30 ft lbs torque as the manual also called for. I have three questions…

(.1) Do I need to use antiseize if the spark plugs don’t call for it? I have the Champion double platinum plugs (part#7034) I looked at the installation guide online and it never called for it. I’m assuming it’s one of those pre-coated antiseize threaded spark plug. I could be wrong and I just want to be safe.

(.2) When I was removing the spark plug wires, four of them came off without too much trouble, however two of em the jacket slid up past where the wire connects to the top of the spark plug. Does that mean I need to replace them? Also wondering why the spark plug wires aren’t really clicking into the spark plugs?.. they just slowly slide up. If I need to buy new spark plug wires just lmk.

(.3) Also wondering if these spark plugs look like they’re normally worn or if they look like I might have problems in my engine.

Sorry the pictures don’t look the greatest as I took them in the dark with a flashlight. If you need I can get some better ones tomorrow in the daylight. Thank you in advance for your time

The Good Twin · May 23, 2024

Upon advice from another member here, I went with the old-school type of plugs. Jeep likes them.

Champion Copper Plus Plug Number RC12LYC Spark Plug 412 | O'Reilly Aut (oreillyauto.com)

Get a new wiring set, distributor cap and rotor. As to using anti-sieze, I would not because the plugs receive their ground from the engine. Just don't over-torque.

As for your current plugs, I don't see anything catastrophic to cause concern.

New to YJ Jeeps · May 23, 2024

Okay thank you. I didn’t think there was anything wrong with them aside from wear but I’m no expert and thought I’d ask

rgreen65 · May 23, 2024

You need to check the recommendation for the spark plugs, depending on your model year. I know it is unlikely that the 4.2 and 4.0 use the same plugs. I know on the TJ there are two different recommendations based on early TJs and later one. I don't know where the change is, I only know the correct ones for my '03 (and the old ones were in for over 129K miles but looked reasonable when they came out, but the Jeep runs better now).

Old school didn't worry about anti-sieze or dielectric as they weren't in that long (10K mile changes along with points and condenser).

Got it at last · May 23, 2024

I would go with @The Good Twin. Autozone will sell you the $10 plug over the $4 plug. Your engine was not designed to run on the fancy irridium split point nuclear powered plugs.
Get the cheap copper core set at 35 and be set

New to YJ Jeeps · May 23, 2024

Lol. What’s done is done though and I’m not taking them back out unless I absolutely have to. I will keep it in mind for next time though.

Got it at last · May 23, 2024

We get a lot of folks report poor performance after a plug change to the higher end plugs.

If you notice a difference in a couple weeks, you may need to revisit the plug choice.

New to YJ Jeeps · May 23, 2024

I hope not 😅. I just replaced the plugs with the same exact part as was already in there. Besides I thought you can only upgrade the plugs, not downgrade… or keep it the same quality as what is already in there?

oldhead · May 23, 2024

Man, I'm old school. Back in the day I used to use a dab of oil on my spark plug threads.

New to YJ Jeeps · May 23, 2024

It would make sense that oil would be a good antiseize. I feel like I’ve heard of using oil but I didn’t just because the instructions didn’t call for it. Something to keep in mind though

Luckymac · May 23, 2024

I use Anti-Seize on my spark plug threads "just because". One trick to use to avoid spark plug problems is to be absolutely certain that the plug is started properly in the threads when you're installing them. Dielectric grease in the spark plug boots and distributor towers can save you problems at the car wash (cleaning the engine) or on the trails at water crossings.

Good Luck, L.M.

New to YJ Jeeps · May 23, 2024

I didn’t use antiseize because I didn’t want to over torque the plugs. I can’t say I’m absolutely certain I started them properly but I did hand tightened them before I used a socket.

Got it at last · May 24, 2024

I'm not the scientist type, but I believe the big factor lies within the way the spark is created and delivered. A rotating arm making contact in the round cap timed off a chain is nowhere as precise as an individual coils hitting plugs signaled by a computer controlling the delivery. You need the longer, bigger spark to ignite the fuel in the older engines. The newer precision delivered spark doesn't have to be as powerful or take as much energy.

New to YJ Jeeps · May 24, 2024

So I ordered some new spark plug wires as well as a new distributor cap and rotor. All the wires were a bit shorter than the old ones but still fit, however the new distributor cap was too large so I didn’t get to change it. I don’t notice any difference in the engine performance which is slightly disappointing. I was wondering how I would know if I did a bad job? Also saw some smoke coming from the top of my exhaust manifold pipe closest to the firewall. I’m going to replace the exhaust manifold hopefully tomorrow with new one I bought, but was wondering if that’s bad that I see a little bit of white/gray smoke? I turned the car off incase it’s bad but I’m assuming it’s just exhaust leaking out somehow?

Spark Plug Replacement…

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