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4.2L from 85 cj

Posted: December 6th, 2010, 5:42 pm
by mtmech
have a 97 tj wanting to do the 4.6 stroker. now my dumb questions. stumbled across a 4.2 for sale. kinda cheap. was wondering if my intake would bolt to it. also my ax15 trans that i have also bolt to it? injectors? etc. also the engine mounts the same as my 4.0L thats in it right now. just askin before i make an offer or make a purchase. thanks. and critisim is welcome. but at the same time... im still learning ALOT by reading.

Re: 4.2L from 85 cj

Posted: December 6th, 2010, 5:46 pm
by 92tank
you use the 4.0 block you have now and put the 4.2l crank and rods in that. you dont use the 4.2l block

Re: 4.2L from 85 cj

Posted: December 6th, 2010, 5:56 pm
by mtmech
figured as much. problem is block i have atm has a hole into the #6 water jet. piston fell apart and the rest was history. not sure why but i figured why i had low oil pressure real quick. after i changed the oil.. filter.. pressure switch.. my next step was to drop the pan. and well after that happened i did and found my piston.

Re: 4.2L from 85 cj

Posted: December 12th, 2010, 4:01 pm
by stroked'73
Tranny will bolt up - might need a different pilot bushing, that's all. Bolt patterns are the same for 258's and 4.0's, as well as AMC 304 and 360 v8's.
But you'd be going backwards with a 4.2, better to find a 4.0 engine or block for sale for cheap. It wouldn't be worth it to put your intake on the 4.2 either - would be a pain to get it to align and even then the head doesn't have the recesses in the ports for the injectors.
No dumb questions here - we're all learning to some degree or another!!