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  #1  
Old February 15th, 2010, 20:36
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austinaubinoe austinaubinoe is offline
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Trucks cheap cherokee build question.

First of all, WHY didnt Jeep use 4.2L crank and rods in there 4.0's?

On the show, the swapped the crank and rods out of a 4.2....then they also bored it .40 over I think. Then they used bigger pistons to make it a 4.7.

The PO of my 2000 blew the 331 head and replaced it with a low milage 97 head. he also replaced all the bearings and gaskets while he was at it. Needless to say it runs great with 150k on the clock.

Im bored with my jeep and need a new project, can I swap in new 4.2 rods and a new 4.2 crank, button it back up and run it?

I dont need to do any machining work if everything else is in good condition correct? Will i need premium fuel (not a problem)


THANKS

Oh and any links to a write would be cool.
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  #2  
Old February 15th, 2010, 20:40
whitexj98 whitexj98 is offline
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Re: Trucks cheap cherokee build question.

Little more involved I believe,

http://www.ajeepthing.com/stroker-motor.html

http://www.naxja.org/forum/showthread.php?t=981968
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  #3  
Old February 15th, 2010, 20:49
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austinaubinoe austinaubinoe is offline
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Re: Trucks cheap cherokee build question.

thank you that first one is an awesome link. This is what I want to do:
4.5L "Poor man's" simple stroker

~ Jeep 4.2L 3.895" stroke crank
~ Jeep 4.2L 5.875" rods
~ Speed Pro 677P standard bore pistons
~ 9.05:1 CR
~ Stock 4.0 HO camshaft
~ Stock HO cylinder head
~ Stock 0.051" head gasket
~ 0.097" quench height
~ 2.25" exhaust
~ Ford 24lb/hr injectors with stock 39psi FPR for '87-'95 engines, stock injectors with stock 49psi FPR for '96 and later engines
226hp @ 4600rpm, 304lbft @ 2000rpm


Since I have a 2000 block with a 97 HO head....all i need is the 4.0 crank and rods (and a couple replacement gaskets). I already have an upgraded exhaust.


Then Im looking at like a 30hp gain!
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  #4  
Old February 15th, 2010, 20:50
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austinaubinoe austinaubinoe is offline
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Re: Trucks cheap cherokee build question.

would probably need 91 octane though right? I really have no idea about compression.

Also, can I still benefit from a set of 5.0 injectors?

was look at performance automotive warehouse and they sell some nice 258 rods. Is it worth it to pay $30 more to get balanced rods, I mean its a jeep, so engine noise isnt a concern .

Last edited by austinaubinoe; February 15th, 2010 at 20:54.
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  #5  
Old February 15th, 2010, 21:22
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tbburg tbburg is offline
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Re: Trucks cheap cherokee build question.

engine noise isn't the concern, engine smoothness/longevity is the concern.

$30.00 for rod matching isn't a bad price, but I wouldn't spend the money for balanced components if I was doing it on the cheap. I'd do it myself. Same with the pistons.

I would have the entire rotating assembly professionally balanced before install though.
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  #6  
Old February 15th, 2010, 21:47
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Darky Darky is offline
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Re: Trucks cheap cherokee build question.

Search in here and also Street & Performace for threads about strokers. There's many running around on that have gone the stroker route.
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  #7  
Old February 16th, 2010, 07:24
multmigs multmigs is offline
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Re: Trucks cheap cherokee build question.

Quote:
Originally Posted by austinaubinoe View Post
First of all, WHY didnt Jeep use 4.2L crank and rods in there 4.0's?

On the show, the swapped the crank and rods out of a 4.2....then they also bored it .40 over I think. Then they used bigger pistons to make it a 4.7.

Im bored with my jeep and need a new project, can I swap in new 4.2 rods and a new 4.2 crank, button it back up and run it?

I dont need to do any machining work if everything else is in good condition correct? Will i need premium fuel (not a problem)

Since I have a 2000 block with a 97 HO head....all i need is the 4.0 crank and rods (and a couple replacement gaskets). I already have an upgraded exhaust.


.
they used the 4.2 internal parts in a 4.0 block to gain the longer stroke, ur posting is kinda hard to follow I think your second post is mistaken you meant to swap the 4.2 crank and rods correct? but that seems possible from what you describe, I thought one of the issues was the use of stock 4.0 pistons didn't allow regular type gasoline b/c the compression turns out to be too high, so most people use a modified stock or custom one and if you are going to all this trouble I guess most people end up having the block machined/checked etc. But I don't see what you can't do what you are describing reusing ur stock parts etc you just have to be prepared for it to a)blow up, b)not run that smooth.... If you can do all this yourself and have a way to easily pull the motor or swap out another I say go for it!
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  #8  
Old February 16th, 2010, 07:43
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seanyb505 seanyb505 is offline
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Re: Trucks cheap cherokee build question.

If you use the KB pistons for strokers I believe the 4.0 rods can be used. You will need new bearings though.
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  #9  
Old February 16th, 2010, 19:22
TomMcD TomMcD is offline
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Re: Trucks cheap cherokee build question.

The first as far as I know, and still one of the best presented stroker builds can be found here.

http://www.bc4x4.com/tech/bryce/stroker/stroker.cfm

Good building.
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