Ok so my original engine is a 1990 4.2L inline 6 engine and I had a cracked piston on it. So I found a 1986 4.2L inline engine to engine swap. Well I noticed that my 90 is setup for v belts and the 86 is a serpentine belt setup. No problem right but someone mentioned to me that I need to take my v belt parts and put them in the 86 because the wire harness for the two years are different. If it had been an 87 to 91, then yes it would be a simple engine swap because the wire harness on those years are the same. My question is this true, do I need to take my v belt parts and put them on the 86 block and head and not have to deal with the harness or keep everything on the 86 serpentine and rewire a new harness?
Question about swapping 1986 4.2 engine into 1990 YJ with 4.2
- Thread starter ZetaPiSigmaChi
- Start date
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- Tags
- engine wire harness
Evening...I'm not sure about the wire harness, but I think your water pump on the serpentine set up is reverse flow vs. the V-belt, so there's that. Not sure if it helps but I found this on the Great Lakes 4 X 4 forum:
'I had a 1986 CJ with the serpitine belt on my 258. I took an '89 258 and rebuilt it then added the main pulley for the serpintine belt. Next I mounted my '86 water pump, alt, power steering, etc. I tension the belt with an idler pully mounted above the alternator...it looks like it was stock - nothing custom as far as I can tell. So you can convert the v-belt version over to the Serpentine, but that idler pulley and mount is the odd ball component that I haven't seen very often.'
Nothing about the harness. The thread can be found here:
https://www.greatlakes4x4.com/threads/258-serpentine-belt.90342/
'I had a 1986 CJ with the serpitine belt on my 258. I took an '89 258 and rebuilt it then added the main pulley for the serpintine belt. Next I mounted my '86 water pump, alt, power steering, etc. I tension the belt with an idler pully mounted above the alternator...it looks like it was stock - nothing custom as far as I can tell. So you can convert the v-belt version over to the Serpentine, but that idler pulley and mount is the odd ball component that I haven't seen very often.'
Nothing about the harness. The thread can be found here:
https://www.greatlakes4x4.com/threads/258-serpentine-belt.90342/
why not repair the cracked piston and save a lot of work , times when i start moving things around, i find myself in trouble. good luck