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4.0 to 4.5L
Posted: April 25th, 2009, 10:30 pm
by smbball32
Sorry if I am beating a dead horse with this question, but I'm new to the whole stroker world. I know that I can take my stock '97 4.0L engine and put a 4.2L crank in it which strokes it to a 4.5L. I have a couple questions about this.
If I am trying to do this as cheap as possible, what do I all need to buy? I will also put a new head gasket on, but in addition to that, is all I NEED just the 4.2 L crank?
What years can I get the crank from?
I know this may be a dumb question, but if I take the grill, fenders, ect off, do I need to pull the whole engine?
Any other tips?
Re: 4.0 to 4.5L
Posted: April 25th, 2009, 11:22 pm
by PolloLoco
Yes the engine will need to be pulled. The route I'm going to go is buy a motor from a 96-98 XJ or TJ (we both have 97s so you may want to go this route) and build the engine slowly, keeping my TJ driveable, then over the course of one weekend swap the motors.
You may need to bore and hone the cylinders, depending on wear to the walls. If the cylinders are bored you'll need new pistons, but it may not even be necessary. Along with the 258 crank you'll need the 258 connecting rods. You can reuse the 4.0 rods if you get custom pistons, but the 258 rods are the cheaper route. The crank can come from a 258 motor itself, just get it ground, or you could buy one remanufactured already. the 4CW crank will probably be cheaper, it's not in demand as much. You'll also need new rod and main bearings. You can reuse your cam, but at the cost of performance. The COMP 68-231-4 is a good replacement cam, but isn't the cheapest route.
Read all the FAQs, there is a great wealth of information: viewforum.php?f=27
Some of my favorite reads for stroker info:
http://www.angelfire.com/my/fan/stroker.html
http://jeep4.0performance.4mg.com/stroker.html <-- your "recipe" will be one of the first few
http://www.rockcrawler.com/techreports/stroker40/
I haven't built my stroker yet, my Jeep is thousands of miles away, but it gives me plenty of time to learn.
Re: 4.0 to 4.5L
Posted: April 26th, 2009, 8:28 pm
by smbball32
How much wear on the walls would I be able to get away with if any?
About how much are new rod and main bearings? Are they installable with out a press?
If I get a new cam, do I also have to get new lifter/springs/ect.?
I would really like to do this with out buying a 4.0 block. I really don't even want to get a 4.2L block either, just the parts off of one that I need.
Re: 4.0 to 4.5L
Posted: April 26th, 2009, 10:51 pm
by PolloLoco
smbball32 wrote:How much wear on the walls would I be able to get away with if any?
I don't know. Most rebuilds require some amount of boring. Someone else should be able to answer.
smbball32 wrote:About how much are new rod and main bearings? Are they installable with out a press?
Haven't looked into prices yet. Federal Mogul is a good brand to get. Clevitte is also reputable, but from what I've read the Clevitte bearings do not have oil holes and you have to put them in yourself.
smbball32 wrote:If I get a new cam, do I also have to get new lifter/springs/ect.?
New springs, yes. Rocker arms will sometimes have grooves worn into them and should also be replace if changing the cam. You do not need to change the cam, in fact there are some people here who haven't. Lifters I'm not sure about.
smbball32 wrote:I would really like to do this with out buying a 4.0 block. I really don't even want to get a 4.2L block either, just the parts off of one that I need.
That's fine too. I just plan on taking a month or two to get everything done and don't want to have my Jeep sitting unused.
Re: 4.0 to 4.5L
Posted: April 27th, 2009, 8:24 am
by smbball32
I would really like not to get the block bored out. Anyone elses opinions? I have have about 86,xxx with oil changes done religously... not sure if that makes a difference or not.
If I do need to get it done, does anyone know of a place around Milwaukee that will do it?
Re: 4.0 to 4.5L
Posted: April 27th, 2009, 8:34 am
by Plechtan
Call Rus at LAM engines in Kenosha (262) 859-3137 He is working on my Bonneville motor and does allot of Jeep engines.
Re: 4.0 to 4.5L
Posted: April 27th, 2009, 8:35 am
by dwg86
Probably won't need boring with only 86,00 miles. A machine shop will be able to measure the bore to see if it has any taper. If it slighty worn you could use a forged piston and have the cylinder honed for the forged piston(a forged piston uses a wider piston to bore clearance).
Re: 4.0 to 4.5L
Posted: April 27th, 2009, 8:44 am
by Plechtan
What is your budget? I would plan on at least $1,000.00 A reground crank can be found for $200 or so, The rods could be anything from free to a couple of hundred depending how/ where you get them. you need all of the gaskets/bearings. plus machine shop work. A new cam and lifters would not be a bad idea, as well as a new timing chain. You may be able to get by with your fuel injectors or you may have to get larger ones.
Things add up fast.
Re: 4.0 to 4.5L
Posted: April 27th, 2009, 6:04 pm
by ajmorell
I'll probably get flamed for this, but yes, you can do this with the engine in the vehicle. Certainly not worth it IMHO but it can be done (a guy on JF did this to his WJ). As much time as you would spend disassembling the motor though you might as well just pull it.
Re: 4.0 to 4.5L
Posted: April 27th, 2009, 8:11 pm
by smbball32
For now I would like to stay with as much stock parts as possible. Sooner or later I'll add new cams/lifter/timing chain. I really don't have lots of money right now, and am planning on a lot more freeway driving next year, so I'd like to have more power with out going all out right now. This leads me to a couple new questions.
I would like to still use the same pistons and rings. Is this a possibility? Is it smart?
What year engine does that crank have to be out of if it matters? As long as it is a 4.2L?
If I get a used crank and rods, what do I need to have done to them? Will the place in Kenosha do it?
Andy- How do you like MTU? Thats where I'm going next year (senior this year...)
Re: 4.0 to 4.5L
Posted: April 27th, 2009, 8:24 pm
by rradford9
I went a similar route with my low budget/simple stroker. If you want to check out my build its here:
http://www.jeepstrokers.com/forum/viewt ... ?f=8&t=645
My total for parts was under 1k and that included some "unnecessary" stuff that you may or may not need to replace. I turned around and sold the CatCo cat (for a profit

) and bought a Magnaflow Carsound Cat instead.
Re: 4.0 to 4.5L
Posted: April 27th, 2009, 8:32 pm
by rradford9
smbball32 wrote:
I would like to still use the same pistons and rings. Is this a possibility? Is it smart?
Possible, yes. Recommended, no. Falcon sells the pistons and rings DIRT CHEAP!
What year engine does that crank have to be out of if it matters? As long as it is a 4.2L?
Any year 4.2L will work. IMO, the "ideal" crank for an automatic is the short snout crank (4cw) out of a '87-'90 4.2L since you don't have to have it cut down or use a spacer. If you're building a manual, I'd try to find a 12 couterweight crank from a '71-'80 4.2L. There is a lot of great info in the FAQ link on this forum http://www.jeepstrokers.com/forum/viewforum.php?f=27
If I get a used crank and rods, what do I need to have done to them? Will the place in Kenosha do it?
The crank and rods will need to be ground and re-sized. The machine shop should be capable of this, but unless you get a REALLY great deal on the crank and rods, its usually cheaper to purchase a crank thats already been re-sized. You will need to have the pistons installed on the rods by a shop. The installation requires the use of a large press.
Re: 4.0 to 4.5L
Posted: April 27th, 2009, 8:35 pm
by Plechtan
Just a guess here, but i think it would be wise to replace the rings, you could use your old pistons if the cylinders are ok and do not have to be bored. You will need the machine shop to press your piston pins in and out. The crank could be a big question mark. Some people have recomended Rock auto (
http://www.rockauto.com) for a crank, probably a something from a 85-91 YJ would be the cheapest. The crank will generally come with new bearings.
Tha machine shop could do all or any part of the work, usually they will hot tank the block and put in new freeze plugs and Cam bearings, but if you don't want to do it, you don't have to.
Re: 4.0 to 4.5L
Posted: April 28th, 2009, 9:03 am
by stroked'73
If you're gonna tear down the motor, get the rings replaced. Not even a question here - doesn't matter how well it was taken care of. Especially since this is going to be a daily driver. Thre's plenty of places to skimp, but there simply is a few that should never be, and I believe this is one. It's not that expensive anyway - buy stock parts - nothing fancy. As far as the cylinder walls, you really have no way of knowing untill you open it up and measure it. Again - if it's your daily driver you want it to be reliable down the road, and that means not cutting certain corners. Would suck to build a motor only to have it blow smoke etc a year down the road when you had a perfectly running motor to start with. Just my opinion.
Someone earlier mentioned getting the crank ground and rods resized. I never resized my rods - didn't even know I had to. I just polished the crank (cheaper) since it didn't need to be ground. If you can pick out a decent looking crank, you can save money on machine work. Also, you can get your stock cam reground to the specs of a cam you'd like - way cheaper than buying a new cam. I'm not knowlegeable enought to recommend new lifters with that or not.
I don't know what a new crank would run you, but first find out how much a shop will charge to grind it if needs to be, and then weigh that against a new crank - might be cheaper if a used crank is given to you or bought cheap. Any 258 crank will work - just do your homework on the snout issue - the links given to you earlier will address all that.
I did mine on the very cheap - had the parts all given to me, basically paid for machine work/labor and all the odds and ends that go with a job like this (and those add up). I spend $1100 at the shop - clean/prep, bore, press pistons, polish crank, basic valve job, install new cam bearings, basic rebuild kit/parts and short block assembly and cam/lifters. If your motor is good and only needs honing, you can eliminate alot of that. If you aren't scared to tackle the assembly and cleaning yourself, eliminate even more.
Bottom line - it can be done, but since this is your daily driver, don't let the power increase ruin the dependability you currently have. Cutting corners is a quick way to do that. I'm not trying to preach or be a prick, just saying what comes to mind.
Mine's not even a daily driver, and I wish I spent more money on some basic stuff while I was in there.
Re: 4.0 to 4.5L
Posted: April 28th, 2009, 11:18 am
by Plechtan
You have to check the cost of regrinding a crank VS a reman that includes the bearings. I checked Rock auto, the 90 wrangler crank was about $171.00 with a $115.00 core charge, A 78 CJ crank was $171.00 with a $40.00 core. You may be able to send your 4.0 CRANK IN as a core, they may or may not catch it. The 78 crank will be a 12 counterweight and have a long snout.