Crank Positions Censor for 4.2 crank in a 4.0L

[66nick66]

Im new on the site but after reading some other posts I see that people know what they're talking about here. So here goes

I had a stroker built for my 1990 YJ (I dont know a whole lot about it) but what I do know is that the 4.2L crank is in the 4.0L block. I was told that I need the crank position censor to make the computer work properly. I have found a kit from Hesco to for a new damper with the CPS on it for $289.

My question is, I saw a site of a company that drills the bellhousing to fit a stock 4.0L CPS. Will that work if the motor has a 4.2L crank in it? Even if that does work should I still spend the extra money and get the conversion kit. Any input would be great!

Thanks,
Nick

[4.whoa]

You didn't say what trans you're running...If its the original one you don't need anything special,just the sensor and flywheel/flexplate from the vehicle its going into-they bolt right up to the 4.2 cranks.Did the shop say why you needed it? I think the front mount setup from hesco is for running a gm trans.

[66nick66]

Good call lol its the Ax-15 that came stock behind the 4.2L in my YJ. I was told that there is no hole in the bellhousing for the sensor to go into. Is that correct?

[4.whoa]

Got me there. I've never had a yj or a jeep with a 4.2l so... I'm sure someone here knows

[amcinstaller]

you would need to cut a hole and mount the cps in the old bell housing. or you could probly find a bell housing from that trans with a newer engine, might have the hole already

[gradon]

Isn't there already a CKP from when the ax15 was behind the 4.2, otherwise how did it get it's timing signal?

[66nick66]

you would need to cut a hole and mount the cps in the old bell housing. or you could probly find a bell housing from that trans with a newer engine, might have the hole already

Thats what I was thinking, Thanks!

Isn't there already a CKP from when the ax15 was behind the 4.2, otherwise how did it get it's timing signal?

I was told that a because the 4.2L was carburetor it didnt have a CPS

[66nick66]

One more question, can I use a stock CPS from a 4.0L if the motor has a 4.2L crank?

[amcinstaller]

i dont see why not

[omegatron]

I'm a little confused...are you swapping computer systems too? Ideally if you're not, just use your old flywheel and tranny. I believe the only reason you would need a crank position sensor is if your current cpu requires one, in which case your tranny has a slot for it and your cpu has the appropriate wire harness to plug it into.

[YJason]

I assume you are putting a fuel injected stroker in place of your carb'd 4.2. I'm not too familiar with the AX15 behind a 4.2, but as said before if yours doesn't have a place for a CPS you can either drill and fab a bracket for one or find a AX15 bellhousing from a newer jeep and swap bellhousings (this is what I would do). You will also need a flywheel from a FI 4.0 also. To answer your other question, yes a 4.0 flywheel will work on your 4.2 crank.