XJ 4.?L Stroker Engine

Bandit1 · 10-10-2009, 12:08 AM

I am replacing my engine cuz it is cheaper to do that than to rebuild the top end, so I am gonna have a spare engine to play with. The engine came from my 00 XJ with 209000 miles on her.

I am thinking that I will build a stroker for the XJ and put it in when it is done, but my question is, how far can you push the 4.0L, and what kinda HP can I get from say a 4.7L? I am not looking at doing anything to crazy with the HP, as I know that a stock 4.0L gets 190HP. I only want about 250ish HP from the build. Any and all suggestions are greatly appreciated. I would like to hear from those of you that have done this as well and your experience.

Thanks to all in advance.

**RockRodHooligan** · 10-10-2009, 12:29 AM

250hp would be easy with a well built 4.6 or 4.7 stroker, by well built I mean with head work, cam, and the needed larger injectors. You'd also be looking at 315+ ft/lbs with either one also. Check out www.jeepstrokers.com for a lot of good info.

Bandit1 · 10-10-2009, 12:48 AM

Quote:

Originally Posted by hotrod_hooligan

250hp would be easy with a well built 4.6 or 4.7 stroker, by well built I mean with head work, cam, and the needed larger injectors. You'd also be looking at 315+ ft/lbs with either one also. Check out www.jeepstrokers.com for a lot of good info.

Thanks, i will be adding that to my many bookmarks...

**RockRodHooligan** · 10-10-2009, 08:46 AM

Here is another one, good to get an idea of different layouts and hp numbers.

Hopefully Monday I will be going to pick up a 4.0 out of an 05 TJ w/13k on it, it's going to be my stroker project. Going with something close to the 4.7L medium-buck stroker, but shooting for roughly a 9.75:1 C/R, and going to port the intake manifold also.

Bandit1 · 10-10-2009, 08:58 AM

yea, i am on a tight budget as most of us are, but i am gonna try to get the most bag for my buck. i am not looking to set any speed records with a jeep, but i would like a lil more pony under the hood for when i get my lift, regearing (4.56), and 33's. thats why i figured that about 250 HP would be good enough. I know that I am gonna take my time in doing this. Though this is not my first engine rebuild, it is my 1st attempt at taking a stocker and making more HP with it. it seems to be fairly straight forward, but i know there is a ton of money, time, and planning involved with it.

The engine I am gonna use for this is the factory block that came with the Jeep. I have another engine that I am in process of installing as the original has a cracked or warped head, and it is faster and cheaper to get the JY one and do the swap. So when all is said and done, the Jeep will have the original block and matching numbers, like it matters much, but it is nice when it can be done

Between machine shop and parts about how much does a project like this run?

Diamond-x · 10-10-2009, 09:13 AM

I built my 4.6l with a 258 crank, 242 rods and KB forged pistons. I milled the deck .020 and run a Comp cam. Injectors were from a mustang off ebay. I also run a K&N as well as a rugged ridge header and 2.5" exhaust, magnaflow HF cat and straight thru muffler.
$1900 in the motor with machining/valve job with Mopar springs, clips, retainers.

I haven't had it dyno'd but it runs strong, I'd guess 50+ HP over the 190 stock. The low end torque is strong and the exhaust rumbles. It does make more heat than a stock engine, a radiator upgrade is advised.

The 242 block is designed for torque and -5000 rpm workload. It wont be a strip engine without extensive mods, beyond stroking. The 7 bearing bottom end is incredibly strong, made to pull.

Be sure your quench is minimal with a 9.7 CR, unless you want to run premium or octane booster.

DC4W-93XJ · 10-10-2009, 12:01 PM

depends on the pistons you use and how much you deck the block..

alot of guys have problems with their compression ratio being way to high.. which makes butt loads of power if you wanna run AV gas

**RockRodHooligan** · 10-10-2009, 01:05 PM

I already thought about the c/r and I actually want to try and tune it for E85 only, 105 octane baby!

Diamond-x · 10-10-2009, 02:22 PM

Stock injectors are 19#. Stroker engines call for 24#. E85 engines will require 30% more fuel (+_31# injectors), shortening your vehicles range. There may also be rubberized parts in the fuel system that may prohibit this idea, since the car wasn't designed for E85.

Set up correctly it'll probably run hard!

**RockRodHooligan** · 10-10-2009, 04:01 PM

By the time I drop this stroker in, it will not be my DD anymore, so range won't be a real big issue for me. I do plan on upgrading the fuel pump as I've heard these are one of the most common fatality's from retrofitting an engine for E85, I'll just have to do a bit of research to find out about the rest of the system, right now it's just an option. As I do more research, if I find it to be feasible I may try and squeeze a little more compression out of it to take full advantage of the ethanol.

**RockRodHooligan** · 10-10-2009, 06:20 PM

Oh and to the OP, where are you from? There is a Rensselaer in Indiana.

Diamond-x · 10-10-2009, 09:54 PM

Fuel pump pressure and injector size are used to determine how much fuel is delivered to each cylinder. Fuel pressure is expected to be 31 PSI stock and pushes fuel through the 19# injector. You'd probably want one that could push 50 psi but again it should be matched with the new 31# injector. I'm not sure if you would have issues with the o2 sensor and E85.

Bandit1 · 10-10-2009, 10:23 PM

Quote:

Originally Posted by hotrod_hooligan

Oh and to the OP, where are you from? There is a Rensselaer in Indiana.

if you are talking to me, i am in NY, moved here from Pittsburgh