Jeep Strokers

Hello everyone,

I've been lurking here for awhile and finally joined up.

I have a 2004 Wrangler Rubicon with 138k on the clock and it's getting tired.

I was planning on a rebuild, but decided since I'm half way there, might as well throw a stroker in the mix.

~I'm planning on getting an 87-early 90 yj crank.
~I'm unsure on rods, I see people using stock 258 rods, as well as the newer 4.0 rods. I tried researching this, but couldn't really find a definitive answer why one is better than the other.
~Depending on how my cylinder walls look in my 04 engine, I would keep it stock bore.
~Planning on adding a cam.
~Also trying to figure out if the factory air box flows enough for a 4.6, if not I'll use the MOPAR Intake for the TJ.
~Unsure on exhaust, but quiet is good.
~Trying to figure out what to do as far as injectors I hear 5.0 mustang ones are good.
~Timing and A/F Ratio, What kind of computer or other adjustments will I need to make for the extra displacement.


My goal for this project is to keep the jeep tastefully modded, I'm going for the sleeper look more than anything, so when people open the hood it looks like a regular 4.0 if that's at all possible. I would also like to try and get a stroker done with out breaking the bank, If it starts getting in the $2500 range I'll just throw a titan or golen in it.

I'm not an entire newbie, I've done engine swaps, transmission rebuilds, small engine, and motorcycle engine work, so I'm fairly mechanically competent.

Terribly long first post, I apologize, I'm just trying to get a few questions answered so I can start parts collecting, and hopefully have a nicely done stroker.

Not even a peep out of anyone?

JeepnBlake wrote: ~I'm unsure on rods, I see people using stock 258 rods, as well as the newer 4.0 rods. I tried researching this, but couldn't really find a definitive answer why one is better than the other.

With 4.2L rods you can use stock 4.0L pistons. However the piston will come out of the bottom of the bore a bit more than with the 4.0L pistons.

With the 4.0L rods, the piston will stay in the bore a bit more. The pistons will have to be custom, Keith Black IC944 forged, Bulltear forged, or some other custom piston. I recommend the Bull Tear. Also, you may get a bute more torque with the 4.0L rod, but I don't know if that is fact or marketing hype.

~Depending on how my cylinder walls look in my 04 engine, I would keep it stock bore.

I wouldn't. Why rebuild the engine if you don't need a bore and hone?

~Also trying to figure out if the factory air box flows enough for a 4.6, if not I'll use the MOPAR Intake for the TJ.

If you already have the mopar then use it. However, there are many better options. For the TJ I like the Banks Power setup.

~Unsure on exhaust, but quiet is good.

Performance wise, quiet is usually never good. However, I have a Gibson 2.5" exhaust on my XJ that is fairly quiet as performance exhausts go.

~Trying to figure out what to do as far as injectors I hear 5.0 mustang ones are good.

won't work on your year unless you use harness adapters. Look for Cobra Injectors. I think mine came out of a 2003

~Timing and A/F Ratio, What kind of computer or other adjustments will I need to make for the extra displacement.

The computer won't bitch about the stroker but a simple piggy back and wideband AFR gauge can help you tune/protect your engine.

Thanks man I really appreciate it!

I would really prefer this thing to run on pump gas, 87-91 octanes, cause pinging is no good, but i'm not sure yet if I should go with the stock,.030, .060 pistons, or if I should just run custom pistons.

After talking to a few smart guys over on pirate I've changed the plans a bit

Updated plan:
~Long Rods
~KB944s
~30lb/hr Injectors
~Comp Cam 68-232-4

Sound good to everyone? Any thing I should change or does this seem like a solid plan?

30# injectors sounds a bit large...most people run 24#.

Probably want a 62mm throttle body also.

Good luck.
Paul

Thanks Paul

I'll be doing the double roller chain, some other mild upgrade stuff like that.

I popped my info into the calculator:

4.6
Long Rod (4.0)
.0215 deck
.051 gasket
kb944s +.030, the faq said the dish is 21.7, so I put 21.7
68-232-4 comp cam

9.1 SCR
7.81 DCR

Shouldn't I be ok running on 87?

anything more than your stock cam will end up forcing your "stock tune" richer at idle, and leaner at higher RPM WOT... keep that in mind when work on this stuff.