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Building stroker need help!
Posted: December 30th, 2012, 11:17 pm
by 240impala
I have a 2003 jeep grand Cherokee I'm building a stroker for I ordered a reman crank from my buddy who owns a napa. I found a good set of used rods from a 258 90 bucks. Now is where I'm having issues I can't find pistons I know if I get new pistons I will have to have them dished to lower my cr but no one does that in my area. Can anyone help me is there an aftermarket piston that is not crazy expensive that will keep me with a decent cr that will not ping or detonate. Also help me if I missed anything. I've read for hours trying to do this the right way.
Re: Building stroker need help!
Posted: December 31st, 2012, 4:54 am
by cruiser54
Re: Building stroker need help!
Posted: December 31st, 2012, 9:37 am
by JeepFamily
Since you are using 258 rods, you can use standard 4.0 pistons. Are your deck height head volume still stock? All stock using a 258 crank and rods, 4.0 pistons, stock deck height and head volume your CR should be around 8.8.
Re: Building stroker need help!
Posted: December 31st, 2012, 10:30 am
by 240impala
I'm all stock my cam and lifters went out so just decided to stroke it. I'm going to get new stock style pistons, I know 03 did not have a problem with piston skirts cracking but ill feel better about new ones.
Re: Building stroker need help!
Posted: December 31st, 2012, 1:44 pm
by JeepFamily
If you need lots of tips, tricks and a parts list I would go to
http://www.angelfire.com/my/fan/stroker.html. Dino provides volumes of important info and is not throwing out lingo to sell you something. From experience, as you dig deeper into what can be done it is amazing how incredibly easy your project grows! I've seen 4.5L 250 HP stump pullers to >5L 700 HP turbo charged monsters. It's truly amazing what can be done with this engine.
Re: Building stroker need help!
Posted: December 31st, 2012, 3:39 pm
by JeepFamily
Oh, though not to speak the obvious, the depth of information, knowledge and willingness to jump in and help from this site and its members are outstanding.
Re: Building stroker need help!
Posted: December 31st, 2012, 4:03 pm
by 240impala
Yeah I'm glad for the help I've been stressing all week
Re: Building stroker need help!
Posted: January 11th, 2013, 9:49 pm
by 240impala
Ok if I leave the stock pistons with the 258 crank and rods with my stock deck height, I will be at 8.8 will my quench be affected. Also I am wanting to get new pistons so there will not be any problems what piston is recommended. I haveno one in town who will dish mine so I'm trying to stay away from that. The machine shops look at me funny when I tell them what I'm building.
Re: Building stroker need help!
Posted: January 12th, 2013, 10:07 am
by Cheromaniac
240impala wrote:Ok if I leave the stock pistons with the 258 crank and rods with my stock deck height, I will be at 8.8 will my quench be affected. Also I am wanting to get new pistons so there will not be any problems what piston is recommended. I haveno one in town who will dish mine so I'm trying to stay away from that. The machine shops look at me funny when I tell them what I'm building.
If you use a 258 crank/rods and stock 4.0L pistons in your 4.0L block with a 0.043" head gasket, the CR will be ~9.85:1 and the quench will be ~0.073" provided neither the block deck nor the head surface is milled.
If the cylinder bores are within factory tolerances for taper and ovality, you could reuse the stock pistons but if you want a lower CR, you'll need to go for aftermarket standard bore pistons. One option is the Speed Pro 802CP. It's slightly shorter than the stock piston so it'll leave the quench at ~0.082", but it also has a 15cc dish so it'll reduce the CR to ~9.5:1.
Alternatively you could buy a set of Silvolite 2229 pistons and send them to
http://www.strokedjeep.com/piston.html to have the dish volume increased. That way you can have the block deck shaved to tighten the quench and set the dish volume to achieve your desired CR. How high you'll set the CR will depend on the cam that you'll choose and the grade of fuel you'll want to use. Keep in mind that if you go for an aftermarket performance cam, you'll need an aftermarket timing set and the earlier style recessed cam bolt/spring/pin with washer to make everything fit properly on an '03 block.
Re: Building stroker need help!
Posted: January 13th, 2013, 3:46 pm
by 240impala
Z677AP anyone know if these pistons will fit my 03 4.0. I hear these have a good dish to achieve a good cr without dishing and still being able to run on pump gas.
Re: Building stroker need help!
Posted: January 14th, 2013, 11:09 am
by Cheromaniac
240impala wrote:Z677AP anyone know if these pistons will fit my 03 4.0.
Yes, those will do fine. Just make sure you get matching Imperial size rings.
Re: Building stroker need help!
Posted: January 14th, 2013, 3:45 pm
by Muad'Dib
Speaking of dishing Pistons, Im not sure if
Oletshot is still active around here... but he dishes pistons (did mine and quite a few others) and does a great Job.
Id recommend supporing a member before looking to outsource

Re: Building stroker need help!
Posted: March 29th, 2013, 12:28 am
by PhantomWJ
240, what pistons did yo end up going with?
Re: Building stroker need help!
Posted: April 7th, 2013, 8:25 pm
by 240impala
I just ordered my crank today, and I'm going with the kb944 pistons so I can use the lighter 4.0 rods. Does anyone know if I have to deck the block any the numbers are pretty close from what i can tell. I only want to do this build one time so your response would be great!
Re: Building stroker need help!
Posted: April 8th, 2013, 5:50 am
by dwg86
240impala wrote:I just ordered my crank today, and I'm going with the kb944 pistons so I can use the lighter 4.0 rods. Does anyone know if I have to deck the block any the numbers are pretty close from what i can tell. I only want to do this build one time so your response would be great!
Your machinist should be able to tell you your deck height after he gets all the parts. Slight differences in block height, and connecting rods are going to determine your actual dimensions. Reconditioning the connecting rods are going to make the slightly shorter. Remember to check the connecting rod to piston clearance. You may have to have the balance pad on top of the connecting rod ground down if it hits the underside of the piston.