OleBlue

The HO block is bored .010 over the renix motor. The only snags I see you running into with using the HO intake and exhaust is that none of your sensors will match up. The throttle body is different on an HO intake so the sensors are different. You need to use the TPS and IAC etc from the HO version and splice them into your renix harness. This is why most people shy away from the conversion.

Also the downpipe is different between the renix and HO, therefore the manifolds are bent different and wont match up to the stock downpipe in a renix. Is your exhaust you have from the downpipe to tail pipe?

BuckB91XJ

Today, I washed Ole Red and cleaned all of the POs crap out of it and vacuumed it out. It was quite a job. I also installed the new hatch struts that the PO provided with it. Then, I installed my cold air intake on it. Just doing that made a huge improvement on how it runs. Somebody has already converted my little 87 RENIX Jeep to a newer and better open style cooling system. However, I will be coming up with a better idea for the overflow tank and a better place to mount it.

zte87

Glad to see you back at it buck!

BuckB91XJ

Today after watching the Seahawks smoke the Rams, I went out and straightened out the front bumper, license plate frame and license plate. As you can see it was dark when I finished with the license plate so that's all I did.

BuckB91XJ

I know it seems pretty pointless to fix something like the bent bumper, plate frame and plate but it was bugging the crap out of me that this otherwise perfect Jeep had that one imperfection on it. The stock bumper will be completely removed when the Jeep is complete. As I was straightening the bumper out I realized that the auxiliary tranny cooler or one of the lines going to it or coming from it was damaged when the bumper was smacked and pushed in. It is a good thing I have another tranny cooler in my garage from my old Jeep if I need to use it.

BuckB91XJ

I have not been able to find anything anywhere that backs up what you said about the 4.0 HO blocks being bored 010. over what the RENIX 4.0 block is. When you lay an 87 RENIX and 91 HO intake side by side the runners and plenum are pretty much identical. So, in my opinion, a guy wouldn't gain anything by swapping one intake for the other. I believe I would gain all the performance I could by just swapping the 91 injectors into the 87 manifold. I just would like to figure how to eliminate the EGR valve from the RENIX motor without causing any problems. I am going to put the 91 Exhaust manifold on my RENIX motor. I believe it definitely flows better and not as prone to cracking. I have to get a hold of a 91-96 "S" pipe because in 91 the O2 sensor bung moved from the manifold to the "S" pipe. So sense the new manifold doesn't have a bung i need to get the pipe that does. Plus with a good "S" all I would need to do is weld a piece of pipe onto my old exhaust that mates up with the "S" pipe and call it a day.

BuckB91XJ

As I was about to start removing the old straight pipe exhaust from Ole Red, so I could install my 2.5" Flow master exhaust, I received a call from a company Called Astronics Corporation located in Redmond, Wa. It appears they saw my Resume on a recruiting board and they are very interested in hiring me. Well, a guy needs a job in order to build his toy so I immediately stopped working on the Jeep and talked to them. I needed to send them a copy of my resume in Word format. Not sure why but don't much care if it gets me the job. By the time I finished on the phone and computer it was dark so, no exhaust work got done tonight. However, I do think I will pull the head off of my old blown up 96 HO motor I have on the stand in my garage. I really think all of the issues with this motor are in the bottom end and that the head is perfect on it. If what I read about the 4.0 HO head casting number (7120) for 91-95 and (0630) for 96-98 having higher intake ports that allow much straighter air flow into the cylinders is true, then swapping my OEM RENIX 4.0 head casting number (2686) for the (0630) head on my seized 96 HO motor should make quite a difference in breathing which = quite a difference (for the better) in power. Because as we all know an engine is merely a glorified air pump.

BuckB91XJ

Okay guys so I pulled the head off of the original 4.0 HO motor that was in my 96 Jeep Cherokee Country.....AND seized solid, when I bought it. You guys remember my pretty little white Jeep that was going to become Project Great White? Of course you do. I did a very detailed thread on the engine swap. I took the bombproof 4.0 HO motor out of my destroyed old gray 91 Cherokee Sport and installed it into the little white Jeep....which is now mine/my youngest daughters rig.....and it still runs like a raped ape to this day. Okay, enough with the history lesson. So, I pulled the head off of that seized 96 4.0 HO motor and well I will let the pictures tell the story. I would say it is an understatement that figured out the mystery of the squashed sparkplug electrode from cylinder number 5. Now, I'm no machinist or professional engine builder but I'd have to say judging by those deep scratches in the cylinder wall that this block is junk....unless sleeving is possible for these engines. The number 5 connecting rod is seized solid to the crank journal. I haven't tried to remove the rod cap yet to see if the rod will part ways with the crank but right now it won't budge.

BuckB91XJ

Here are a couple more pictures that show the nasty deep scratches on the cylinder wall. Looks pretty bad.

BuckB91XJ

The good news that goes along with all that bad from the two prior posts this, the head from the blown 96 motor is fine. A little clean up with a wire brush and a new head gasket and I will have a perfectly good 1996 4.0 HO head casting number 0630 to put on my RENIX motor to help it breathe better. You can see from the pictures how the intake ports are higher than the exhaust ports. the intake and exhaust ports are in a straight line on a RENIX head. I also had another pleasant surprise. My 96 HO head casting number 0630 does have a bung for the water temperature gauge in the back left corner of the head. I read that the only difference between a 91-95 HO casting number 7120 head and a 96-98 HO casting number 0630 is that the 0630 heads don't have the temp. gauge bung in the head...mine does!!

OleBlue

Hmm, I may be wrong on the 010 over. I swore i read that somewhere but everything I find about specs now says nothing about it. Thanks for correcting me=D

BuckB91XJ

Hey Buddy you have taught me just as much, if not more, than I have taught you. We need each other to keep the other guy honest so we put the most accurate information possible out to the young guys. I look forward to your posts on my threads.

SHANE 87

When i get back from training and get another rear axle in we'll have to do some wheeling

BuckB91XJ

Hey, Shane! Howzit going buddy? How is the Army life treating you? I'm looking forward to getting my lift put on the new red jeep so I can see how the rims I got from you and the 35" Cooper Discoverer STTs I have on them will look on it. Is there a chance of you getting stationed at Joint Base Lewis McChord or are you trying to go somewhere else? Yes, we will have to get together sometime soon and go wheeling. I think this new Jeep is really going to turn out nice and very capable.

BuckB91XJ

So, me being the Jeep 4.0 HO enthusiast that I have been for my entire Jeep Cherokee experience as you all know. I am determined to get as close to HO performance out of my newly bought 87 4.0 RENIX motor as I can. I have been doing a lot of research over the past couple of days. While it would more surgery than I am interested in doing, to transplant an entire HO motor, it's ECM and wiring harness into my pretty red 87 XJ. I am, however, seriously considering an entire HO top end (e.g., an HO head from a 96 HO motor and intake, TB, injectors, fuel rail and exhaust header, from a 91 HO motor. I've read a lot of threads about various combinations of HO pieces being used on a RENIX motor. While an HO head can be used with a RENIX intake manifold, and the motor will run, the ports are enough mismatched that I don't believe the motor would run good and give the full amount of potential power through the entire RPM range. I've read the HO IAC is plug and play with the RENIX wiring harness. However, a little customizing needs to be done to the RENIX TPS to get it to work with the HO throttle body. I also read that an HO throttle cable and tranny cable need to be acquired from a donor HO XJ. Once I get all of the pieces rounded up I will do a post with pics on this thread of how it goes together for me. Everybody have a Happy New Year. I don't know if I will be back on the CF before tomorrow.