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Renix to H.O. swap worth the hassle?

R

Renegade XJ

NAXJA Forum User
Location
corona ca
I have an '89 XJ with 198k. Im going to start putting money aside for when my engine dies out on me. But, I was thinking, why bother rebuilding the old Renix if I could just swap in a nice low mileage 4.0l H.O. out of a newer XJ. What years would be a good match? and would it be worth it over rebuilding? All the Jeeps I have ever had have always been 4.0l H.O.'s except for this XJ and my JK, power wise my XJ does OK.... I just hate all the vacume lines EVERWHERE under the hood. The H.O.'s seem more pratical and simple. Any advice? If I did do the swap what are some issues I might have and what will I need?
 
Re: Renix to H.O. swap worth the hassel?

If you stay in the 91 to 95 range it's a bit easier. . Just strip the donor motor down to "long block" configuration and begin swapping over all your Renix stuff: distributor, flexplate/flywheel, sensors, valve cover, intake and exhaust. Be sure to use the intake/exhaust gasket for your Renix vintage motor to ensure a good seal.
 
Re: Renix to H.O. swap worth the hassel?

I see you're in the People's Republic of Kalifornia. What will they say if you eliminate all the original Renix vac lines? Besides, it's easier to just get new vac harnesses. They don't hurt anything.
 
Re: Renix to H.O. swap worth the hassel?

I did this on my 4-cylinder and it was a pain because I got everything piece by piece from the junkyards. You'd be much better off to get a whole donor vehicle if you can get it for a good price so that each time you think of one more thing you forgot you would need you can simply walk over to your donor and pull it off. Little parts get expensive. I like the end result though. I based mine off of a '93 year ('91-'95) and went from there, getting the new intake manifold, brackets, throttle body, wiring harness, cables, flex plate, etc. It's a lot of work.
 
Re: Renix to H.O. swap worth the hassel?

xj92 said:
I did this on my 4-cylinder and it was a pain because I got everything piece by piece from the junkyards. You'd be much better off to get a whole donor vehicle if you can get it for a good price so that each time you think of one more thing you forgot you would need you can simply walk over to your donor and pull it off. Little parts get expensive. I like the end result though. I based mine off of a '93 year ('91-'95) and went from there, getting the new intake manifold, brackets, throttle body, wiring harness, cables, flex plate, etc. It's a lot of work.
Click to expand...


Yea thats the plan! Im think of looking for a low mileage wreck that I can get cheap. Then pull everything under the hood out of it.
 
Re: Renix to H.O. swap worth the hassel?

If memory serves... in California, you cannot swap an older vintage engine into a newer
model car (ie: putting a '88 motor into a '90 car).

You can swap equivalent year engine/car (ie: '92 engine into a '92 car).

You can also swap a newer engine into an older car (ie: '98 engine into a '90 car)
BUT the car will have to pass a smog inspection (includes emissions sniff at the tailpipe)
for the standards of that year of engine (ie: an '88 car with a '94 engine will have to
pass a smog test inspection as though it were a '94 car). That means all of the plumbing, fuel injectors, vac lines, catalytic converter, computer...etc. that comes on
a newer engine ...will all have to be swapped in, also.
 
Re: Renix to H.O. swap worth the hassel?

rebuild the renix and swap on the ho head, 99 and up intake and throttle body, and be done with it.no computer swapping bs. but with the better power of a newer model
 
Re: Renix to H.O. swap worth the hassel?

yeah, Renix FI is a better system than the Chrysler junk anyways.

always was able to get more torque and better mileage from worn out old renix motors than that newer ho junk.

I dunno how many miles are on my 89, the odometer quit working at 276180 and that was back in 2004 according to the title records, it's a one owner Jeep and she never did anything more than brakes, fluids, and suspension related work
 
Re: Renix to H.O. swap worth the hassel?

I'm a fan of the OBD I and even more the OBD II systems but in your case I would just swap the long block. If you swap the engine crap you will have to swap the rest of the engine compartment electronics, which will require you to swap the dashboard wiring too... and at that point you may have to swap the wiring heading into the back of the vehicle also. This all assumes you are going to plug connectors together and never cut and splice anything, if you know your way around automotive electronics and don't mind spending a couple days of quality time with a DMM, wire crimper, and two FSMs (for your jeep's year and the donor's year) you can probably patch it all together with much less.

It's something I would not feel like undertaking, and I'm an electrical engineer... unless I was stripping the vehicle down anyways, it seems like way too much work for the results.
 
Re: Renix to H.O. swap worth the hassel?

Nope.

You'll need to modify things such as the throttle position sensor and idle air control motor to fit. An auto RENIX XJ will require custom electronics or a custom adapter (Hesco makes one iirc) to make both the TCU and ECU happy about the TPS signal at the same time.
 
Re: Renix to H.O. swap worth the hassel?

MaxxTraxx said:
A 99+ HO head/intake and TB will direct swap on to a 89 XJ as stated by 88xj?

That would be a nice upgrade...
Click to expand...
its not hard. i was rebuilding the motor anyways so i just got an ho head so the ports would line up with the 99 intake, i built a tps adapter and used the stock 88 tps, and a newer model throttle body, and throttle cable. also had to change to the newer model powersteering pump and bracket set up with a 99" belt.
 
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