First Stroker

[DoubleOXJ]

I recently found out that my 2000 XJ has a cracked head. So being the normal Jeep guy I figured I'll just pick up a junkyard motor and build it up and replace it. However, you cannot just build it up stock, whats the fun in that. I decided that I would go for the ultimate budget stroker. I am liking the 4.5L style. Upgrade the crank and rods to the 4.2L version and run an standard rebuild kit. I just emailed TeamAMC about a crank and rods so hopefully I can get this project in motion soon. I pick up my 94 XJ motor next week and will begin the tear down. Is that truly the only thing I need to do to this motor other than the standard overhaul stuff? Can I use an OEM cam? I am new to this whole thing so please bear with me. Thanks, any info is good info!

[DoubleOXJ]

OK I am tearing my hair out trying to figure all this stuff out. This is what I have so far...

94 Jeep 4.0L (From what I can tell its a non HO)
Pre 1981 4.2L Crank and Rods

I am planning on using an OEM camshaft, pistons (oversized), lifters, pushrods, rockers, valves, etc....

The problem I keep running into is that everything says I need a ported HO head. I don't have that, will mine still work? I plan to put my 2000 XJ intake manifold onto the 94 head and run headers for the exhuast.

The other issue I have read is that the 2000 xj computer has a hard time running anything with any significant performance mods. They recommend a "unichip" which is another multi-hundred dollar investment. Has anyone run into this?

I don't want to be able to smoke my 32" tires. I just want a bit more power than a stock motor. I am planning on rebuilding this 94 motor anyway and I am about to say screw the whole stroker project. I thought I had a pretty decent grasp on how motors work but this is all giving me a headache! Please lend me some knowledge.

[Dezertxj88]

Your doing it right don't worry. I was once going to do a OEM 4.0 stock stroke rebuild, with a .60 over bore to unshroud valves. Then I talked with Dino a littlle about the 4.2L crank and now theres a bunch of info out there. Jeepspeed guys have been doing this forever though, its just always been kinda kept quiet.


The only way you get a 4.2L is with a .60 over. Stock 3.875" bore & the 232 crank is a 4.05L, .030 4.1, .060 4.2L!
You have a HO head. Ho refering to the high output 4.0. 91+ was high output. 87-90 were low output Renix. Porting would be nice but no not needed at all!
I would buy new lifters, just get a oem replacement set for 50 or a set of aftermarket for 80. Stock cam will be run, springs should be fine so long as they are within spec. Valves, I would clean them up, install new valve seals ectect. I would also see about having your machine shop "back cut" you valves. It will help flow a little more.

You can have it tuned at most any shop with a tuner & a dyno. You can use a map adjuster that cost about 50, or get a Apexi Safc II for about 200...its just a more glorified and more precise map adjuster. Can add/take fuel at more points ect.

[SilverXJ]

94 Jeep 4.0L (From what I can tell its a non HO)

HO started in 91 so if it is a 94 its an HO. Get the casting number off your block and see here: http://www.jeepstrokers.com/forum/viewt ... ?f=34&t=52

I am planning on using an OEM camshaft,

Your stock cam shaft won't work in the block. If you get a new OEM cam shaft get the one for the block you are using along with a timing set for it.

The problem I keep running into is that everything says I need a ported HO head.

You don't need a ported head, but it wouldn't hurt. However to correctly port the head you would need a flow bench and quite a bit of knowledge. What you could do is clean it up a bit. Just clean up the casting a bit and polish the intake and combustion chambers. However, being that you are going to fit an earlier head to a 2000 vehicle you will run in to two problem 1) The coil rail will need to be supported in some manner. A couple of straps off the valve cover bolt/studs will be fine. You could also swap it out for a Viper coil pack and some self made ignition wires. See here: http://www.jeepstrokers.com/forum/viewt ... =26&t=2756 2) the stock exhaust manifold isn't a good fit on the earlier head. I would recommend an aftermarket header for your 2000 vehicle. The header will cover the ports nicely.

The other issue I have read is that the 2000 xj computer has a hard time running anything with any significant performance mods. They recommend a "unichip" which is another multi-hundred dollar investment. Has anyone run into this?

With the stock cam that is BS. The only time the stock PCM will have issues is with an aftermarket cam with specs far from stock. What you would want are a new set of larger injectors. I recommend Mopar 53032704AB from a 04-06 Jeep 4.7L HO. They are 4 hole and flow about 25 lb. Or the Neon 0-280-155-784 Injector, which flows about the same is is also a 4 hole design.I am currently running the Neon injectors. They are the best fit I have found for my 2000. I would also recommend a wideband O2 sensor setup with data logging. Its not necessary but it will let you see what your air fuel ratio is. You will most likely be running a bit rich on the top end with those injectors though. With out any kind of tune (PCM or piggy back) you may be leaving some power on the table. If you are inclined to modify the air fuel ratio I would recommend the AEM FIC 6.

Your doing it right don't worry. I was once going to do a OEM 4.0 stock stroke rebuild, with a .60 over bore to unshroud valves.

You don't need a .060 over bore if you just want a bit more power over stock. The way I read it you don't want to go balls to the wall and empty your pockets to get all the power that can be had. Also, going with a smaller bore (.020, .030, .040, etc) will allow you one or more rebuilds if necessary.

The only way you get a 4.2L is with a .60 over. Stock 3.875" bore & the 232 crank is a 4.05L, .030 4.1, .060 4.2L!

I have no idea what you are saying. He said he is going to use a 4.2L crank, which even with a stock bore would yield 4.5L.

I would buy new lifters, just get a oem replacement set for 50 or a set of aftermarket for 80. Stock cam will be run, springs should be fine so long as they are within spec.

He will NEED new lifters and a proper cam break in as he can't use his 2000 cam in the 1994 block.

You can have it tuned at most any shop with a tuner & a dyno.

Not many shops have the equipment to tune the JTEC PCM. He could send it off to get the PCM tuned or go with the AEM FIC or as you said the APEXI.

[Dezertxj88]

Your doing it right don't worry. I was once going to do a OEM 4.0 stock stroke rebuild, with a .60 over bore to unshroud valves.

You don't need a .060 over bore if you just want a bit more power over stock. The way I read it you don't want to go balls to the wall and empty your pockets to get all the power that can be had. Also, going with a smaller bore (.020, .030, .040, etc) will allow you one or more rebuilds if necessary.

Correct it isn't needed, .060 over is purely my preference!

The only way you get a 4.2L is with a .60 over. Stock 3.875" bore & the 232 crank is a 4.05L, .030 4.1, .060 4.2L!

I have no idea what you are saying. He said he is going to use a 4.2L crank, which even with a stock bore would yield 4.5L.

I was stating with a 232 crank, stock bore =4.05L, .030 over 4.1L, .060 over 4.2L for others who read. He's building a 4.2L from my understanding ..he's been Pm'ing me so I just carried over from those, which was why it was confusing, should of read his OP as well. But in the pm's hes said he was using a 232, 3.8L crank to make a 4.2L. But now reading his OP he states he wants a 4.5L..I think he wanted the 4.5L but now is doing a 4.2L mini stroker lol.

I would buy new lifters, just get a oem replacement set for 50 or a set of aftermarket for 80. Stock cam will be run, springs should be fine so long as they are within spec.

He will NEED new lifters and a proper cam break in as he can't use his 2000 cam in the 1994 block.

I think I misunderstood here because I didn't read his OP to find out he's building a 2000, I just carried over from pm's where he was asking about a 94 lol. I thought he was building a 94 & reusing that 94 cam? IF thats the case he could buy replacement sealed power lifters for 50, or aftermarket like the Comp cam savers for around 80. Either way I told it him to just get new ones, its not worth the hassle to reuse high mileage stock ones.

You can have it tuned at most any shop with a tuner & a dyno.

Not many shops have the equipment to tune the JTEC PCM. He could send it off to get the PCM tuned or go with the AEM FIC or as you said the APEXI.

Again I wasn't clear...turning into a habit I ment tuner, as in a person to tune it lol..
I was refering to in pm's about using the simple map adjusters..and then taking it to a shop to have a tuner tune it lol.