5.5 hemi spark plugs

[gto64gto]

I was reading about a member changing plugs on his truck. There were several replys about not using iridium plugs on a hemi. Why? I have a Harley and I know I'm talking about 2 different vehicles but I have done alot of research on iridium plugs. In test after test, they bring down the cylinder temperatures as they transmit heat to the head better than other types of plugs. I have seen the results from different plugs and they do bring down temps. If some one has a technical reason why this is not correct, I would like to hear it. (I'm not trying to be a smart a--) I would really like to know. If you use the correct iridium heat range as the stock plug, it should let your engine run cooler because it transfers more heat from the cylinders. Thanks.

 

[misfit77]

As far as I've seen it's based on year of truck as well. I've seen some post saying my 2014 dies not get iridium, but my plugs are 100k or so plugs....silly but o just assume they iridium.

When that day comes, I will just cross reference on part number and buy the same.

 

[Pull Ya]

It appears that you have done your research on spark plugs. All I can tell you is in my experience with the early model 4th gen Hemi's, they do not run well on anything other than the cooper plugs as suggested by the factory. If your research shows that is not the case and the factory is misguiding us, then by all means use the plugs of your choice--it's your truck, your decision. Also I'm no expert but I've never heard of a 5.5 Hemi? What years were they built?
Jay

 

[misfit77]

Also consider that if you are switching from copper to iridium and your truck does not run well that is one expensive experiment.

16 x whatever iridium cost these days = too much

 

[MarshRam]

Sometime in mid to late 2013 they changed out the copper plugs.

From what I have read, it is not that those 2013 and under models with copper plugs can't handle the iridium plugs. It is the coil packs they came with that are not accepting. Guys stated they swapped with the proper coil packs and they run fine and you get the benefit of the 100k spark plug. I have never done this myself or personally know someone who did.

I can tell you from personal experience that I did put iridium plugs in my 2007 4.7L TRX4 once and did not swap the coil packs. It did not run right. Swapped back to copper and I was good to go.