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which spark plugs?

zedpapa

NAXJA Forum User
Location
san diego
i put a 2002 grand cherokee 4.0 in my 89 and now its time to replace the plugs. the engine only had 25,000 miles on it so it still had factory plugs. my question is, should i get the plugs for the year of the engine or the year of the cherokee? I am using all the 89 electronics including the "distributor"

zedpapa
 
I'd be very surprised if they aren't the same plugs, since it's the same engine... just make sure they're gapped properly for the engine and I think you'll be fine.
 
the engines ar not the same. the heads are different, the blocks are different, the cam is different and the 02 motor makes about 20 more horsepower. i spent two weeks drilling and tapping holes to be able to get this engine to bolt in to my 89. those are the external differneces in the engine. i have no idea about the internals other than the cam. the plugs in the 02 4.0 have a projected tip and the 89 4.0 does not.

zedpapa
 
yikes! sorry about that, didn't realize the 4.0 changed after the last Cherokee model year. I'd probably use the plugs recommended for the WJ then... though this is way past what I really know anything about.
 
You want plugs for the year/make of the vehicle that engine came from. (unless you swapped the head). For example, my friend has a mid 80s Chevy full size . It originally had a 305 POS, he replaced it with a 350 from an 89 full size van. He asks for engine parts for an 89 full size van..
 
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