[Matt87YJ]

I chose replaced... But I went the way of a stroker. Best mod to date.

[yunkj17]

dang looks like you will have a nice motor when you you are done

[johnrezz]

Not a backdoor advertisement at all. How often do you read about bad experiances? This is basically my way of sharing good ones. These guys have been great to deal with and like to share photos as the project goes along so I post them.... no different than I would if I was doing the work. That being said, if you want an engine done right in NW Colorado, these are the guys "I" recommend.......

That being said here is the break down of HP based on the engine buildup. (taken from an email sent from Jorin, the guy building the engine, I did not ask for it he just sent it. This is the kind of service that I will always pass on.)

I have run your build through our engine simulation program, DynoSim Pro Tools, and came up with some interesting information for you.

1st I put a basic 4.2 engine together with the std 4.0 head (Non-HO) and the 4.0 camshaft used in the 90’s models and came up with 182 HP @ 4700 rpm and 236 Ft lbs @ 3500 rpm. These are within a few HP and FT lbs of the factory ratings on the early 90’s 4.0’s.

Then I ran another test with your build, I ran a 4.0 HO head with the Comp Cams camshaft, .020” overbore, Clifford single plane intake, and 500 Holley and came up with the following: 251 HP @ 5000 rpm and 307 Ft Lbs @ 3500 rpm.

I think that these specs are going to be very close, especially since the 1st measurement was so close and also since several builds that I have seen of the conversion have been right around there as well. You may end up with a little more horsepower than I calculated but this is at least a very solid simulation for you. I can even print out a copy of the simulations for you to look over if you would like. The information contained would be good learning material. The simulation covers Cylinder pressures, Volumetric efficiencies, HP, HP Loss due to friction and pumping effects, Torque, Induction airflow, piston force, piston speed, mechanical efficiency, and more!

I show that this engine should need 345 cfm at full horsepower, this equates to about a 416 cfm maximum carburetor size required to support the power, so the 500 will be a little oversized but will work just fine. I have seen a batch of people use the Holley 390 4 barrel on these too. What this means is that the 500 may get just a little worse fuel mileage due to the fact of the each venturi being larger since there is only 2 on the 500 instead of 4 smaller ones on the 390, causing more fuel on acceleration to be induced than the smaller carb at approximately the same acceleration rate.

Hope you found this interesting, and the short little commentary on the 4x4 forum too.

Talk to you later,
Jorin

[johnrezz]

Now I am just waiting on my new Clifford intake that I ordered a long time ago, apparently it is "raining" in California. Remember those bad experiances I talked about

J

[sam.b.]

subscribed, ive been waiting for a engine build like this. its EXACTLY what i want to do with/to mine

[johnrezz]

Well, I had to wake the old girl up from her winter nap so I can do the engine swap this week......
She drove right out of the snow, it took me over two hours to get my pickup out of the same hole...... Jeeps rock!!!!!



Here is what is going in.......258 w/ 4.0HO head 5 angle head job, Comp Cam, bored.020, clifford intake, holley 500CFM carb, CRT HEI Dist, and other nice touches.........






Engine work done by:


http://www.jtrengines.com

[machinehead131]

looks sick

[JaikYJ]

Yeah that my friend is a thing a beauty, looks like money well spent.

[johnrezz]

nobody noticed that there is a stock 4.0 exhaust manifold with a clifford intake, All you have to do is shave a little off of the intake to make clearance for the exhaust. The reason I am pointing this out is that I have seen this asked alot of times and I was told that it could ont be done.
I did not think the header was worth the money to HP gain, the design of this exhaust is not bad, I might gain a few horse but not $300.00+ much. I do plan on increasing the exhaust pipe to 2 1/4" back to the muffler.....

[Gonewhln]

Super nice job i hope it all goes back together easy so you can get it out and enjoy the snow.

[johnrezz]

Should be ready to go next week, I am going to pull the old engine tomorrow replace the heater core and the blower motor (upgrading). I will have to figure out the exhaust after I drop the new engine in.
I am not a big fan of the Jeep in the winter, too damn cold here -10 to -20 every morning, plus with big tires it is horrible in the snow so I basically park it for the winter......

[machinehead131]

Originally Posted by johnrezz

Should be ready to go next week, I am going to pull the old engine tomorrow replace the heater core and the blower motor (upgrading). I will have to figure out the exhaust after I drop the new engine in.
I am not a big fan of the Jeep in the winter, too damn cold here -10 to -20 every morning, plus with big tires it is horrible in the snow so I basically park it for the winter......

Yeah, I hear ya on that.

Once mine warms up its not bad but on the highway in the snow it gets hairy with 12.5 wide tires.... they just loooove to float over the snow and slide all over.

In town its great, 4wd and mass snow everywhere with no problems.

[MLJeeper]

Looks nice! the torque numbers excellent.

I would definitely get around to the roller rockers sooner than later though. Ever since my drag racing days i have found that roller rockers are one of the most worthwhile mods you can do, especially to a rebuilt engine. Makes the idle and revs much smoother and extends the life of your guides BIGtime. Add in the fact that the the rollers reduce friction and that the stock rocker arms are worn (your not getting full lift anymore) and you typically get a nice little boost in power.

[johnrezz]

Yeah, they are just real exspensive for this motor for some reason..... For the amount of gains I decided that a new intake was a better investment, I might add them when the funds show themselves....... Right now I think I am going to spend the remaining funds on a new radiator and better gauges.....

[johnrezz]

Well, it was a late night but the new engine is in and running strong. We finished up around 2:00am..... There are still alot of little loose ends to tie up but it was great to hear it run, and it sounds awesome!!!!!!

I will post pictures soon