Ian96XJ

That's it. I'm gonna do it. Time to have the engine rebuilt. I was originally going to drop in a 4.6 Stroker, but after doing a lot of research, I think I'm going to back out of it. Other than the money, am I *really* going to use all that power? No. I'm not a huge rock crawler. And the horror stories I've heard and the requirement for 91 octane.... Ugh.

So, I think I'll just have the engine rebuilt. Nothing seriously wrong with it right now. It just feels tired; it kinda struggles going up hill, even with the mods in my signature. And I do a lot of desert exploring in it. I don't like the feeling of always wondering if I'm going to be stranded.

My question: is there anything I should ask the machine shop to do to take advantage of and maximize the mods I've already put in? I'm basically looking for more torque. Would a port & polish make a difference? Rocker cams? (Those two might be for more hp, which ain't bad, but at the expense of torque?) Bonus points if you can recommend a shop in San Diego. I'm looking at Total Performance in Santee and Kenyon Machine in Clairemont. Thanks all!

Cherokeekid4x4

Are you trying to keep it stock or "trick" it out? I just got my new motor in. These motors when running right already have enough torque. It's the big tires and worn out gears that diminish that.

Ian96XJ

Not really tricking it out. I was going to buy and pop in a 4.6 Stroker, but I'm chickening out. I just talked to a performance guy. What I'm looking to do is get as much torque as I can without changing displacement. So he suggested a very minor port & polish type of job, changing the cams, and that's about it. He said that a fresh engine may surprise & impress me.

I'm now considering buying an engine core and giving that to him so that he can take his time and rebuild it. Says it'll take him around 3-weeks to a month.

Outlaw Star

Port n polish is more for top end/higher RPM performance. You don't need to run higher octane in a Stroker as long as your ignition system is in great order. Higher octane is used for two reasons 1) High Compression or 2) High RPMs. Neither really apply to the 4.0L. I ran my 4.9L on 87 octane. A good cam will help shift your powerband either lower or higher depending on what model you choose.
Any questions, don't hesitate to send me a PM.

beatricethexj

If you are trying to keep it relatively stock and just get some more oomph. I would suggest shaving .010 from the head or block with a .043 head gasket and either advance the stock cam or replace it with one of your liking. This should bump up the compression without using 91.

Here is a good thread on cams
https://www.cherokeeforum.com/f67/ca...156711/index5/

1st jeep owner

Change the factory computer program first, and see if you're happy with the difference. I personally did a 60mm throttle bore, polished with spacer, 4 hole injectors, and a comp can with lifters. More than I personally need. One has to remember that Cherokee's are the fastest production small SUVs on the market, with OR real capability. The engine is a monster torque machine, so why mess with it, unless compelled or in need of repair? I mess with my wife's because she's clueless under the hood or suspension, and I want to. I bought her the Cherokee didn't I?

andrewmp6

I would go a little bigger cam and light head work for just enough power you feel.

Ian96XJ

UPDATE:

I ended up buying another engine to have the shop (Total Performance in Santee, CA) work on. It was just a logistical nightmare to get the current engine out and to the shop. The shop comes highly recommended.

They've taken the donated motor apart and say it all looks good. They will contact me next week regarding options. All of this is still very confusing to me, but I'll try to take some time this weekend to educate myself. Of course, I will take everyone's input into consideration. Thanks!

Fred/N0AZZ

You can balance the rotating assembly and a complete race prep of the block and head. This is what I'm doing with the engine that is being built by the shop that has built all my race engines for the last 17 yrs. Use nothing but the highest quality parts in the rebuild, that goes for gaskets as well.

Makes for a very smooth running engine with good oil flow and better than normal life/durable.

Ian96XJ

I'm sure that's in the plan. The shop is actually a racing engine shop. They are top of the line, so I've been told. But I'll make sure it's done. Is there a recommended manufacturer of gaskets?

Ianf406

Ive always used the fel-pro rubber ones with great success. They seem to last twice as long as any of the cork ones.

Ian96XJ

Decided to upgrade to the Hesco water pump. Might as well replace the old one and the t-stat (yes, and HF t-stat housing, too). Maybe I'll upgrade to the 116 (?) amp ZJ alternator since I have an extra bracket and time to grind. But that can always be done later.

Fred/N0AZZ

Do you know how much a full race prep on a block/heads (porting cleanup) runs? I have no idea on a 4.0, but know very well on a SBC or a Dart Block (SBC 400) and Dart Aluminum Heads. It has only one head and 2 less cylinders to do on it, a lot of people build race engines costing from what they claim as one for as low as a few k to well over $200,000 turnkey.

Machine work can make or break any engine build and most any shop would not go to the trouble for a 4.0 build of doing everything a race engine gets, but IMHO it was worth it to me and he die it for free. I guess that I must have paid for it over the years all the engines he built for me.