poormans 4.5 stroker?? Help!?!

[davidlepsch]

i just bought a 99 4.0 motor that i plan on putting a 258 crank and rods into. I already have a full ignition kit, 62.5mm t.b., cat back exhaust, intake. I want to run pump gas and make this motor with as little money as possible. Is it possible to get a good crank out of a 258 with reconditioned connecting rods and use new std. size piston and rings? And what kind of outcome would I have? I'm also using the stock head with mostly stock valve train besides mopar springs and retainers. Or would there be a better way thats cheaper? and what injectors. Thanks a bunch any help is appreciated! If someone could give me exact part numbers and parts to use that would be awesome.

 

[gradon]

How many miles are on the 99? If a lot, I'd go ahead and bore it out .030-.060"(might as well and get some more power). If your looking to run pump gas, get stock size pistons with the biggest dish or pay someone <$100 to dish them to low-mid 20ccs. I used the Sealed Power H802cp30 w/ 15.5cc dish(~$150) and the 4.2 rods. If you haven't bought the 4.2 rods(roughly $120 recon'd), you could use the 4.0 rods and spend ~$200 more for some forged KB944 pistons w/ 21.7cc dish(seems like they're ~$500 w/ rings, but that extra 7ccs per piston can mean the difference b/t 87 and 93 octane). Injectors are going to depend on what setup you're gonna use: Renix and OBD1 w/ 39psi and returns or OBD2 w/ 49psi and what wiring harness(99+ use ev6 connector injectors, <98 use ev1 connectors).

 

[davidlepsch]

Ok then the motor has 164k on it and i could bore it out .030" im looking to run probably some 91 octane pump gas. I'm going to go with the 4.2 rods. I'm trying to make it a daily driver if at all possilble and it will be going in a 98 xj with mods listed above, so its going to be in obd2 w/ the 49psi with 98 wiring harness.

 

[davidlepsch]

Ok then the motor has 164k on it and i could bore it out .030" im looking to run probably some 91 octane pump gas. I'm going to go with the 4.2 rods. I'm trying to make it a daily driver if at all possilble and it will be going in a 98 xj with mods listed above, so its going to be in obd2 w/ the 49psi with 98 wiring harness.

 

[Dr. Dyno]

With 164k miles on the block, I would definitely advise reboring the cylinders. You could go +20 thou or +30 thou which would leave enough meat for a second rebore should the block need it in the future.
I love my +20 thou "poor man's" stroker (stock '92 cam) but if I had to do it all again, I'd use 4.0 rods and KB944 pistons with the CompCams 68-231-4 cam (and Mopar 5249464 springs and Mopar retainers), making it a 4.6L version of the "medium buck stroker" recipe on my site.

 

[AIbandit]

I'd use 4.0 rods and KB944 pistons with the CompCams 68-231-4 cam (and Mopar 5249464 springs and Mopar retainers), making it a 4.6L version of the "medium buck stroker" recipe on my site.

Any reasons why you would go with that?

 

[POLAR_JEEP_04]

where is the best place to get KB944 pistons?

is this them?
http://www.summitracing.com/parts/UEM-KB944-030

can they be found cheaper else where?

 

[davidlepsch]

what year 4.2 crank, 4.2 connecting rods, bearings, .020 pistons, head gasket, new bolts? should i use? and is there any other modifications needed to put this all together or is it just direct bolt in/ons ? Should I do anything to the head thats cheap enough while its off too, besides clean it all up? And what kind of mileage should i see out of this if its done properly? Assuming proper maintnce and daily driving + a little offroading.

 

[Dr. Dyno]

http://www.summitracing.com/parts/UEM-KB944-030

can they be found cheaper else where?

The part no. has changed to http://www.summitracing.com/parts/UEM-IC944-030/

Any reasons why you would go with that?

Tighter quench, 9.6:1 CR, and more HP/TQ. The only downsides would be a noisier valvetrain due to the stiffer springs and the faster ramp rate of the Compcams, and cold start piston slap due to the forged pistons. Just a question of whether you can live with the engine sounding like a diesel at idle.

 

[Dr. Dyno]

what year 4.2 crank, 4.2 connecting rods, bearings, .020 pistons, head gasket, new bolts? should i use? and is there any other modifications needed to put this all together or is it just direct bolt in/ons ? Should I do anything to the head thats cheap enough while its off too, besides clean it all up? And what kind of mileage should i see out of this if its done properly? Assuming proper maintnce and daily driving + a little offroading.

Any year 4.2 crank from '72 up will do.
Any year 4.2 rods will do. Just use new ARP rod bolts.
4.0 and 4.2 rod bearings are the same. You'll need 4.0 main bearings (not 4.2) for a '99 block.
Victor-Reinz or Mopar Performance head gasket (0.043" compressed thickness).
New head bolts.
You can port the head while it's off and have it milled for flatness.

Everything bolts straight in.

 

[AIbandit]

The only downsides

As for downsides I was thinking more of a cost thing then a noise thing.

10 Hp Gain from about 500$ more cost? (pistons and rod reconditioning. Comparison vs PAW rods/Speed pro pistons.)

 

[davidlepsch]

ok so i think im going to use 87-90 crankshaft, the 4.2 rods, 4.0 bearings, .020 pistons, new rings and all arp bolts. What kind of power numbers would i be looking at and what about motor longevity and mopar h.d. oil pumps or hi vol. pumps?

 

[AIbandit]

Read http://www.jeep4.0performance.4mg.com/stroker.html
then go to www.jeepstrokers.com and read more.

 

[ChevelleSSLS6]

Hastings rings... I swear by 'em. Slighty biased as I can see the factory where they're made from the fiancee's front yard. I'd also visit their site and look under 'tech tips' for proper break in procedure.

I like schneider cams too. Check them out.

 

[Dr. Dyno]

As for downsides I was thinking more of a cost thing then a noise thing.

10 Hp Gain from about 500$ more cost?

Yeah, the extra cost for just 10-15hp more does sway the bang-per-buck ratio heavily in favour of the "poor man's" stroker provided, that is, you can find a good set of 258 rods for less than $200. They're becoming harder to find cheap though.

 

[AIbandit]

Cool just wanted to make sure I'm not missing something.