Hey guys. I tried searching but couldn't find an exact answer. My step dad found someone selling a 91 4.0 for $390. So I was wondering if it would be worth it to swap the 91 4.0 into my 87 that has a RENIX 4.0. Also, what parts would I need from the donor to put in mine? Another thing, what parts for the 87 4.0 that I already have will swap to over to the 91? Thanks in advance guys!

 

Also, don't know if this will help, but here is a link to the posting.

http://dallas.craigslist.org/dal/pts/5443117905.html

 

Post 17
http://cruiser54.com/

 

Cruiser’s HO into Renix Swap

This swap is easier than some will lead you to believe, generally those who have never done it. Those of us who have done it, like myself, will share with you the things that need to be done for a successful swap. Just think of it as swapping in a long block.

The HO and Renix have some differences but none that can’t be overcome very easily.

Any HO engine from an XJ or ZJ through 1999 can be used. One running change was that the rear of the head was no longer drilled and tapped for the temperature gauge sender beginning in the 96 model year. The sender can be relocated to the threaded hole in the thermostat housing taken from the HO engine. You’ll have to extend the wire to that location. Some brave souls even drill and tap the HO head for the sender.

You will be using the intake and exhaust manifolds from your Renix, along with all your sensors and wiring. Since the intake ports of the HO are slightly different, you use the Renix gasket. Exhaust ports are identical.
You will need to use your Renix distributor as it is different than the HO because they use different fuel management systems. The flywheel or flexplate from the Renix must be used so your CPS gets the correct signals. The valve cover from the Renix allows you to keep your CCV system intact and requires no modifications.

The HO block will have a plug in the coolant galley on the driver’s side of the block, closest to the front, which needs to be removed so your Coolant Temp Sensor can be installed in it’s place just as it is on the Renix. It requires a 5/16” square drive or a modified 3/8” drive that has been ground down to fit. Do this before installing the engine.

As for the knock sensor, which is located just above the oil pan on the driver’s side of the engine about mid way, all the blocks I’ve seen are threaded for it. If not, I’ve heard they may be drilled but not tapped. Tap the hole if that’s the case.


Revised 03/28/13

 

So, basically if there is nothing wrong with the block or the head, there is no point in swapping it? I think if I have any problems, they would be something electrical based, not mechanical.

 

I'm confused now.

 

I was just going to swap engine, computer and everything. Not reuse any RENIX stuff. But if that's not worth it, there's nothing mechanically wrong with my 87. The block and head are fine. I was going to swap the newer system in.

 

what are you hoping to gain?

 

A newer engine with less miles. Slightly more power.

 

Is there an echo in here?

 

if the renix is working then there is nothing to be gained by doing a swap, you wont gain much HP and no extra torque i believe, youd be better of putting that $300 into a lift or tires lol

 

your going to gain only 17 hp and no torque, i wouldn't do it

http://www.jeepforum.com/forum/f11/c...k-specs-26256/

 

That's what I was thinking. Just wanted the opinions of others that have/may have done the swap. Thanks guys.

 

Yup.

HO myth buster


Renix in 90 made 182 HP. HO in 91 made 190 HP. That's 8 HP difference.

HO only made more HP than Renix at higher RPMs and not a bit more torque. HO had 58 mm throttle body versus a 52 mm throttle body on a Renix and also had a better design header. See where I'm going with this?

The whole 8HP was not mostly from the head, but from the bigger TB and better exhaust manifold.

Put a 60mm TB from www.strokedjeep.com on your present head, eliminate the "crush" in your headpipe with proper re-routing, and go for it.

HO stands for Highly Overrated.
__________________

 

The final straw for me at the 'other' site.


Got so F'ing sick and tired of hearing about how rotten Renix is and how much better a MJ is with the HO swap.........yadda yadda.......

Site owner's sidekick is full of ****.


Had it with him running his mouth......and when his full swap started giving him troubles....I jabbed.



Anyway.......OP, if it runs well, leave it be or make it better. Nothing wrong with our Renix Jeeps, once you understand them you can work on them just as easily.