Jeep 258 Crank into XL 4.0...Yes or No?

1996 XJ Sport (185,XXX)

Blew the head gasket and cracked the "Banks" header. While I was in there I decided to replace the harmonic balancer, timing chain and gears, oil pan gasket and just about everthing to do with cooling the motor is also getting changed out. Since I am already in there.

I've read a couple of articles about swapping in a 258 crank that will get you to 4.6L/4.7L. From what I've read it doesn't sound much more difficult or expensive to do the swap than a standard motor rebuild.

Has anyone done this swap, and is it really as simple as throwing in the crank (aside from machine work and other standard parts) and either swapping shorter pistons or shorter con rods?

If so how noticeable is the power/torque increases and what pros or cons are there if any?

Since I'm only a few bolts away from the motor being out and the head is getting re-done, I thought it would be a good idea to also rebuild the bottom half.

Your thoughts...

TONs of build threads on this sublect here. Go to street and preformance.

Search "Stroker" here, and /or try http://www.jeepstrokers.com/forum/

What he said ^ jeepstrokers has everything you need.

Thanks for the info and quick replies!

Is there a desirable year to get the crank from? Friend is looking at doing a 4.5 stroker with no over bore. He has a few 258's around but wanted to know if one was better then the other.

If you are running a manual tranny you should go with the heavy counterweighted crank, with an auto, go with the lighter crank. Either will work, but what I outline will meet most peoples needs the best.

it'l never work:confused1



ignore the 12 weight crank. to make power, you need a light rotating assembly. 12 weight isn't worth the time to find. get the 4 weight with the short nose.

and i am running the 12 weight, and wish i got the 4.

cheap? not really, sure is fun though

tomcat said:

it'l never work:confused1



ignore the 12 weight crank. to make power, you need a light rotating assembly. 12 weight isn't worth the time to find. get the 4 weight with the short nose.

and i am running the 12 weight, and wish i got the 4.

cheap? not really, sure is fun though

Click to expand...

12 weight is definitely better with a 5 speed. with and automatic you dont need the weight

are the 12 weight proponents people that have built and run the motors, or just read an article somewhere?

I have 80K+ on my stroker and have run it for probably 8 years. I started with the AX-15 and the heavy crank. I have since converted over to an auto. The heavy crank doesn't allow the motor to rev up quite as fast. Not a big problem.

You're right, too many people are web experts and have never built or driven a stroker.

ive crawled with an ax15 and both a 4 weight and eventually swapped for the 12 with much success because of the things i read. i put probably 15k on the motor before swapping out the crank. in my 99 i used a 4 weight with the aw4. once spring hits that will be going in.

tomcat said:

it'l never work:confused1



ignore the 12 weight crank. to make power, you need a light rotating assembly. 12 weight isn't worth the time to find. get the 4 weight with the short nose.

and i am running the 12 weight, and wish i got the 4.

cheap? not really, sure is fun though

Click to expand...

the 12 weight crank lugs better with the manual trans. but the lighter is better for automatic

I like the 4-wt in my street xj w/ the ax15. It picks up revs quick. If you do any off-roading where you tend to idle over objects, then get the 12-wt. Do your stroker research and learn what parts you need to make it happen(you'll need 258 rods as well or $350-600 pistons in addition to the crank off the break).

ive got fresh crank, fresh rods and beaings for a spare motor if your interested