inline242 Posted August 23, 2007 Share Posted August 23, 2007 I'm wondering if the engine swap will work? Link to comment Share on other sites More sharing options...
DirtyComanche Posted August 23, 2007 Share Posted August 23, 2007 Sure. But why? The 4.0 is a better motor. Link to comment Share on other sites More sharing options...
FxRacing282 Posted August 23, 2007 Share Posted August 23, 2007 theres no replacment for displacment Link to comment Share on other sites More sharing options...
JeepcoMJ Posted August 23, 2007 Share Posted August 23, 2007 yea there is, it's called fuel injection. a 4.2 is OK but I'd beef up the 4.0 before putting a 4.2 in...carbs suck Link to comment Share on other sites More sharing options...
Eagle Posted August 23, 2007 Share Posted August 23, 2007 Are you sure of the year and engine in the Wrangler? The Cherokee and Comanche went over to the Chrysler injection/ignition system beginning in model year 1991. I thought the Wrangler was changed over to the MPFI 4.0L the same year. If it's a 4.2L it'll have a carburetor, and despite the added cubic inches the 4.2L puts out less power and (I think) less torque than the injected 4.0L. Link to comment Share on other sites More sharing options...
DirtyComanche Posted August 23, 2007 Share Posted August 23, 2007 Regardless of rated power, all the 4.2L carbs and emissions systems are in such horrid shape, at this point, that there's no way it'll make rated power. Link to comment Share on other sites More sharing options...
Rob S Posted August 23, 2007 Share Posted August 23, 2007 91 was the first year the 4.0 was in the YJ. It was a HO. If it is actually a 90 4.2 carb'd engine, save it for parts when you build a stroker, otherwise it makes a good boat anchor. Link to comment Share on other sites More sharing options...
rockhardzj Posted August 23, 2007 Share Posted August 23, 2007 otherwise it makes a good boat anchor.I love unique looking anchors... Get some really funny looks throwing that old head into the water as others cruise by... Link to comment Share on other sites More sharing options...
CMMagnussen Posted August 23, 2007 Share Posted August 23, 2007 Interesting idea.......... Wouldnt knock the 4.2 too much iv seen people turn them into animals with little effort (ill be doing it on my SX/4 soon) 4.2 with 4.0 head and fuel injection system can be fun..... or for us muscle car fanatics (me) 4.2 4.0 HO head decked and ground, header, offenhauser 4bbl intake, truck avenger carb, TFI ignition, and not sure where I'm headed with the cam........ yeah they are right though....... that stock carb needs to go to hell..... Link to comment Share on other sites More sharing options...
FxRacing282 Posted August 23, 2007 Share Posted August 23, 2007 just put in dome pistons and a torque cam and a edlebrock 650 or 750 dual feed and then say its got no power! injection systems work too. if you can try to get a chevy 4.3 as they are a very nice engine and arent to hard to come by. someone should make the conversion for the tranny. Link to comment Share on other sites More sharing options...
1bolt Posted August 28, 2007 Share Posted August 28, 2007 my opinion brown like everyone elses so take it for what it's worth, by the time you get done bolting on pieces and throwing money at a 110-ish RWHP 4.2 you'll have somewhere around the power of the 140-ish RWHP 4.0 HO... I have rebuilt two, added TBI injection to one, swapped aftermarket cams into four, swapped a 4.0 head onto one, done a half dozen exhaust mods to just my 88 YJ alone, and I've never ended up impressed with any 4.2 that wasn't blown. My 4.6 stroker in my XJ on the other hand is bad @$$ and makes me happy about my work on it, money well spent. Link to comment Share on other sites More sharing options...
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