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Motor Swap

M

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NAXJA Forum User
Location
Courtenay BC Canada
Hey guys new here been reading around and finding lots of good info....

Anyway I bought a 88 XJ that has low oil pressure when hot and makes one hell of a noise when you rev it up. I have yet to check the flex plate, but I don' think that's what is making the noise. I think its either the Rod or Main bearings..... Any way onto my actual question. I have found a 91 XJ fully loaded for sale for $500 and i was wondering will I have to change any electrical over with the little bit new motor? Or are they both on the Renix system still?

Thanks In Advance
Matt
 
the 91 should be a h.o. motor... ive never dug further than that into it but i would think eletrical and computers would have to be swapped... not to meantion that the exhaust down pipe should be different...
 
You can put a 91 (OBD1) motor into a Renix w/o problems.

1. Use the 91 engine, but all sensors, wiring, comp., flywheel/flexplate stay Renix--sweet and simple.

2. Use the 91 engine, but upgrade to OBD1--not so sweet nor simple. You would have to move all the donor sensors, computers, re-wire or move wiring harness, flywheel/flexplate.
 
Yes swap all the sensors, flexplate, alternator, and fuel injectors from the old one. The TPS need to be adapted to work on the HO TB, either with the Hesco adapter, or make one. The easy way would be to take the whole intake manifold, fuel rail and injectors off of the old and onto the new. Just dont forget the flywheel/flexplate. You could also do everything the hard way and use the HO electronics, this would involve swapping the entire wire harness.

Just swap the intake and get er done.
 
sounds like lifter rattle to me.. I too have the same noise.. and 0 oil pressure at hot idle.. I'm in the process of replacing the lifters in oil pump to see if I can nurse it a while longer.. if you had more oil pressure, the lifters may not rattle.
 
jaqattack02 said:
If I have a 1991 which already has the HO 4.0 in it, how much trouble is it to swap in a 4.0 from one of the later models?
Click to expand...

Slip Kid said:
Yes swap all the sensors, flexplate, alternator, and fuel injectors from the old one. The TPS need to be adapted to work on the HO TB, either with the Hesco adapter, or make one. The easy way would be to take the whole intake manifold, fuel rail and injectors off of the old and onto the new. Just dont forget the flywheel/flexplate. You could also do everything the hard way and use the HO electronics, this would involve swapping the entire wire harness.

Just swap the intake and get er done.
Click to expand...
 
That doesn't answer my question, that was answering how to put an HO engine into a non-HO Jeep. Mine already has the HO engine. My question was is there much of a difference from the HO engine in my 1991 Jeep compared to one from a later Jeep. I have found an engine from both a 1994 XJ and a 2001 available locally, and want to know how much trouble it will be to use one of them.
 
jaqattack02 said:
That doesn't answer my question, that was answering how to put an HO engine into a non-HO Jeep. Mine already has the HO engine. My question was is there much of a difference from the HO engine in my 1991 Jeep compared to one from a later Jeep. I have found an engine from both a 1994 XJ and a 2001 available locally, and want to know how much trouble it will be to use one of them.
Click to expand...

1991-1995 OBD1, 1996-2001 OBD2. OBD1 and OBD2 don't count on much in the way of sensors, wiring, electronics, and I don't know about the flywheel/flexplate issue between the two systems. As stated above, convert engine to current setup in your rig, or if going OBD2 change everything.
 
jaqattack02 said:
That doesn't answer my question, that was answering how to put an HO engine into a non-HO Jeep. Mine already has the HO engine. My question was is there much of a difference from the HO engine in my 1991 Jeep compared to one from a later Jeep. I have found an engine from both a 1994 XJ and a 2001 available locally, and want to know how much trouble it will be to use one of them.
Click to expand...

94 into a 91 is a direct swap(91-95) are the same ob1. 96 and up is ob2 and some difference in head design and fuel rail, but should drop rignt in as they use the same sensors i believe. if the sensors are different, you should be able to just swap the sensors. the 2001 is distibutor less and uses coil packs, but has a spot for your dizzy. it also depends if your doing a short block or long block swap. i would not do the 2001 for the simple fact that the head is prone to cracking.

you should do a search because many swaps of many different years have been done.

"how much trouble" depends on what you concider as trouble. lets just say a 96 and up engine has been done in a 91. search will bring up more details.
 
joe_peters said:
1991-1995 OBD1, 1996-2001 OBD2. OBD1 and OBD2 don't count on much in the way of sensors, wiring, electronics, and I don't know about the flywheel/flexplate issue between the two systems. As stated above, convert engine to current setup in your rig, or if going OBD2 change everything.
Click to expand...

i believe the flexplate/flywheel is the same from ob1 to ob2. a simple parts number lookup on rock auto or napa should provide a concrete answer.
 
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