1990 yj 4.2

[RCYJ]

hey i am strongly considering buying a 1990 yj. it has the 4.2 inline 6. the current owner says he has all records for the rig including mods. dose any one have any experience with this particular engine? are there any common problems with them i need to be aware of? or would i be better off going for the infamous 4.0?... i am buying a jeep i expect to do a lot of repairs just not to the engine. any information will help!
thanks
Robert

 

[JOOP]

hey i am strongly considering buying a 1990 yj. it has the 4.2 inline 6. the current owner says he has all records for the rig including mods. dose any one have any experience with this particular engine? are there any common problems with them i need to be aware of? i am buying a jeep i expect to do a lot of repairs just not to the engine. any information will help!
thanks
Robert

Only problem with that engine is it's carb'd. I have a 90 YJ. It had a 4.2 that got replaced with a 4.6 stroker. (Same block bored and stroked) But an easy fix is to get a Howell EFI kit (GM TBI and GM Ignition) and convert it. It's easy enough to do in 1 day. Once you do that it will run upside down, honestly.

 

[RCYJ]

Only problem with that engine is it's carb'd. I have a 90 YJ. It had a 4.2 that got replaced with a 4.6 stroker. (Same block bored and stroked) But an easy fix is to get a Howell EFI kit (GM TBI and GM Ignition) and convert it. It's easy enough to do in 1 day. Once you do that it will run upside down, honestly.

about how much would it run me just a rough estimate?
you like you jeep? what are your mods on it? the one i am looking at has a 6in skyjacker lift and 35" Micky Thompson baja claws. cable lockers. that is all i know of for right now.

 

[JOOP]

about how much would it run me just a rough estimate?
you like you jeep? what are your mods on it? the one i am looking at has a 6in skyjacker lift and 35" Micky Thompson baja claws. cable lockers. that is all i know of for right now.

I got my kit from CustomEFIs.com . The guy is a **** and takes forever to ship. But a Howell kit available online runs about $1200.

Yes I like my jeep. It's a little more than just bolt ons these days. You wont need a 6" lift to fit 35''s. I originally had skyjacker 4" leafs and a 1 inch body lift. Thats all you need to fit 35's

Here's my mods
4.6 stroker with GM TBI
AX-15 5 speed
NP213 t-case with AA Heavy Duty shaft and SYE kit
3 linked up front with 14" Radflo air shocks
4.5" BDS leafs in the rear
1" MORE body lift
6 point DOM cage tied into the frame
Full belly up skid
2.5" exhaust with a flo-tech twister
High rise tube fenders
36" Irok's
Hybrid Dana 44, Alloy shafts, Chromoly gears, Warn Hubs, Detroit locker
Ford 8.8/ disc brakes, with Detroit
4.88 gears
Tom Woods front and rear driveshafts. Rear is a CV

I'll find a pic and post it.

 

[RCYJ]

damn dude sounds like i could learn a thing or 2 from ya a pic would be amazing! god i want to ask so many questions but idk where to start and dont want to sound like to much of a fool!

 

[JOOP]

Oh forgot I have rock lights too

a pic before the high rise fenders

Here's my build thread LINK

 

[JOOP]

I know YJ's pretty good, ask away. I'm here to help. IMO they are one of the best building platforms to start with.

 

[RCYJ]

wow! looks great! i gotta sighn off for a while thanks for your help! ill definitely be asking for some help and ideas!
thanks again

 

[RCYJ]

i gotta think on what i want to ask ill get back to ya thanks. to start off did you do any axel swaps? unfortunately this is also my daily driver too:booo:but i want to get it as mean as i can and still drive it im gonna see if i can get some pics up of the jeep im lookin at

 

[Lincolnlock]

Buy a 91' and up jeep. Without fuel injection they are problematic and a handful on the trail.

 

[JOOP]

i gotta think on what i want to ask ill get back to ya thanks. to start off did you do any axel swaps? unfortunately this is also my daily driver too:booo:but i want to get it as mean as i can and still drive it im gonna see if i can get some pics up of the jeep im lookin at

Yep. I have a Hybrid Dana 44 up front out of a Wagoneer (Hyrbid just means it's built with chevy/ford/and AMC parts, plus all Chromoly shafts and gears). In the rear I have a Ford 8.8 axle. The rear 8.8 is an easy swap for YJ's. Almost a direct bolt in. Some people just slap them in and run them. I put a 1.5" spacer in the passenger side and moved the perches to recenter the axle. This fixed the miss-alignment of the pinion and gave it the correct width. Some people just run it with the pinion slightly off angle.

 

[boxboy]

Get the 90 and just plan on dropping a new Hemi into it when it starts acting up. You can also take all the 1995 4.0L FI and put it on the 4.2 parts are easy to find and there are write ups all over the web.

Make sure it has the AX-15 and not the peugeot


But the price needs to be "right" you can get a highway driven TJ for cheap and a stock TJ will out wheel a mod'ed YJ any day... I would look around for a TJ with a 4.0 5 speed put a RE lift maybe a Ford 8.8 rear some 35" and be done...

 

[JOOP]

Get the 90 and just plan on dropping a new Hemi into it when it starts acting up. You can also take all the 1995 4.0L FI and put it on the 4.2 parts are easy to find and there are write ups all over the web.

Make sure it has the AX-15 and not the peugeot


But the price needs to be "right" you can get a highway driven TJ for cheap and a stock TJ will out wheel a mod'ed YJ any day... I would look around for a TJ with a 4.0 5 speed put a RE lift maybe a Ford 8.8 rear some 35" and be done...

If it's a 4.2 it's a AX-15. All the 90+ inline 6's came with them. I think even an 89 did.


I dont know about that Stock TJ out wheel a moded YJ statement. Thats a bold statement to make:flipoff: I guess it depends on what mods your talking about.

 

[JOOP]

Buy a 91' and up jeep. Without fuel injection they are problematic and a handful on the trail.

Because of the carb.

 

[boxboy]

If it's a 4.2 it's a AX-15. All the 90+ inline 6's came with them. I think even an 89 did.


I dont know about that Stock TJ out wheel a moded YJ statement. Thats a bold statement to make:flipoff: I guess it depends on what mods your talking about.

Sorry but 1990 is a mixed year you will find both trannys and 3 different unit bearings...

 

[boxboy]

I dont know about that Stock TJ out wheel a moded YJ statement. Thats a bold statement to make:flipoff: I guess it depends on what mods your talking about.

I have a tj with a 4.5 lift on 35" and it will out wheel your jeep any time any place:corn: it force me to 4-link my 90 Jeep because it pissed me off:booo:

 

[JOOP]

I have a tj with a 4.5 lift on 35" and it will out wheel your jeep any time any place:corn: it force me to 4-link my 90 Jeep because it pissed me off:booo:

Your nutts. :haha:

and you said stock. TJ:flipoff:

Why do you think I linked mine??

 

[RCYJ]

at the risk of sounding like a newb (i really am) what dose linked mean?

 

[JOOP]

at the risk of sounding like a newb (i really am) what dose linked mean?

Instead of leafsprings up front I have a Long arm suspension with nitrogen air shocks. LINKED

 

[RCYJ]

oh ok that makes seance. what do i have to do to up load pics?