Jeep Strokers

I just joined this site recently and I've been reading the FAQ's and scouring a bunch of the threads for info and tips for quite a while. I've gotten a pretty good idea of what I'd like to do with my '97 XJ and my '02 WJ already. Both engines are currently running in good condition and don't burn oil or loose coolant. They have fairly high miles, but not excessive (for a 4.0) by any means. The '97 XJ has about 148K and the '02 WJ has 108K on the odo. The goal is to gain some useable HP and TQ without compromising MPG. The 02 WJ is completely stock and just seems a bit too underpowered for towing duty. The XJ is sort of a DD/toy and is modified extensively with the exception of the engine. (lifted w/ 35's, 4.10 gears, Ford8.8 & D44 axles, etc...)

The basic (4.5L) formula I plan on using for both engines will be: (Using the original 4.0 block from each vehicle)
4.2 12wt crank - w/ new bearings, balanced- spacer made from the old HBs
4.2 rods - recon'd w/new bearings, balanced
4.0 pistons (original ones in engine if possible, see Q below) - weight matched with new ring sets
4.0 block from each vehicle - basic prepped (magged, tanked, cyl honed, .000 decked, new cam bearings)
4.0 head - basic prepped (magged, tanked, valve job, port gasket matched), make suface flat and polish chamber out to 60cc
stock 4.0 cam and lifters and valve train (may get new OEM ones if needed)
MP/VR .043 head gasket
High vol oil pump (Melling?)
Double roller timing set
TB bored out to 60mm (done by me, already on XJ)
24lb injectors (already on XJ)
2.5" exhaust with high flow cat and flowmaster (already on XJ)
'99+ intake (already on XJ)

There's a lot of info on dishing the aftermarket pistons, but I haven't been able to find any info on using and modifying the stock pistons. So, my question is: How far I can dish the OEM pistons? (assuming they can be dished at all) For both of my builds, that will determine whether I will use the 4.2 rods and the stock pistons or the 4.0 rods and aftermarket pistons.

I'll be building the engine for he XJ first and then once that is up and running reliably the WJ will get it's turn.I'm trying to keep both the builds as similar as possible so I'm not having to reinvent the wheel when I build the second one. Cost is also very a big factor for me since I'm going to college full time right now. That's the main reason for trying to use as many of the original parts as possible. I'm not opposed to aftermarket stuff, but the more aftermarket parts I have to buy, the longer the build will take. The college I go to has a Automotive Tech program here so I can get some help with the swap at very reasonable prices. I'll still have to pay a shop to get the heavy machine work done, but I'll be doing everything else that I can do myself.

The simplest stroker build is my modified "poor man's" recipe where everything inside the engine is stock except for the 258 crank and Keith Black IC944 pistons.

I've seen that build and it's probably the one I'm closest to using. I've actually spent a lot of time on your website revewing your builds before I found this website. Lots of great info in there!

However, what I'm currently trying to find out is: Can the OEM pistons can be dished (safely) beyond the factory spec of 13.5cc or not. If so, How far can they be taken out to?

I'm sure someone here has to have already checked this option out before. I highly doubt that I'm coming up with any new ideas this late to the Jeep stroker game. My search-fu just isn't strong enough to find the info out there on the interweebs apparently.

I wouldn't reuse a high mileage piston/bore. There is a chance there is a ridge at the top of the cylinder, but using 4.0l pistons+4.2L rods that may be avoided. The bore will also most likely be tapered, larger at the top. There is also a chance that the pistons will distort or be damaged when being pusher off the wrist pin/.

Thanks for the input SilverXJ. I hadn't thought about the possible distortion factor from removing them from the pins.

The more I'm thinking about it, the more appealing those 944's are looking. It's looking like there will be to many compromises associated with trying to retain the OEM pistons. If I do go with the 944's (I most likely will) it just means that I'll have to save up for the parts a little longer before I can begin the build up. I don't want to pull the XJ engine right now since it's still working fine and I won't have all the needed parts for a while anyway.

I had a set of Sealed Power cast 677cp's dished to 26cc with no issues.