So i waited for pick n pull to have a 50% off sale day and grabbed a 96 grand cherokee 4.0l that wasn't blown up or molested. The trans pan was off it so i rolled the dice. It was like 150$ if i remember right.
Did a ton of research on strokers and quickly realized the only pistons worth a shit for various reasons came from a guy named russ pottenger in southern CA. Very knowledgeable guy who builds jeep strokers for desert racing classes requiring the amc 6 remain.
My idea was tight quench and aluminum head to help avoid detonation,run on pump gas and have higher compression for higher torque!
Got a new scat crank for a serpentine belt 4.2l/258.From 89-90 jeeps i believe(they fit my tj front accessory drive).
scat 4.0l length forged rods modified to have light chevy wrist pins.
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comp cam 68-231-4, 206/214 duration,.462"/.485" lift, custom ground 113* lsa for jeep fuel injection and nitrided.
.030" over forged pistons with the correct compression height to have zero deck without milling the crap out of the block and an 18cc bowl that better matches the fast burn 57cc chambers on my edelbrock cylinder head.
.040" mahle mls head gasket
Mild casting cleanup on the head and blended the seats into the bowls. Marked and unshrouded the valves a bit. cc'd the chambers after. With a tight quench of .040". Russ cc'd the pistons to be 10.2:1.
He said pump gas would be fine and it does great with 91. 87 and octane addive works in a pinch if i don't lug it.
View attachment 391957had a local machine shop assemble the rotating assembly for me and did the rest myself.
Used a banks revolver header russ recommended.no cracks in 20k miles so far.also used a horseshoe intake because why not. Had to drill and tap blank bosses in it for the sensor harnesses to reach and a little vacuum line work. Not an issue.
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Used these 280155703 bosch 24lb dodge neon injectors. Motor runs good on stock injection with no tuning. Hp tuners compatible Wideband and some flyin ryan tuning would probably help unlock mo powa.
Had some issues with a couple lifters being duds off the bat.replaced them(a small amount of clearancing of the pushrod holes on edelbrock heads lets you change lifters with the head on
) and it still has more lifter noise than stock. Nature of the beast with cammed 4.0ls.
Replacement part quality is horrible.especially valvetrain parts.this is why strokers get a bad rap.though the parts that make it a stroker, ie crank,rods and pistons aren't something you see failing if done right.
I also went with a Centerforce 700469 High Inertia Flywheel for the hell of it. Figured it couldn't hurt and might help smooth out the almost 1/2" extra stroke and higher compression. Centerforce standard flywheel is listed as 27.5lbs and this one is a hair over 40lbs.stock luk clutch. Factory flywheel with the taper was long gone.
Love how it drives. Very torquey. Great offroad low rpm power.4.10s and 33s it pulls 8% grades locally in 5th and 2k rpms.holds 10% grades in 4th easily and will accelerate up them.I do wish I'd let russ put LS v8 valves in the head and step the relatively mild cam up larger. More power would be sweet even if its unnecessary. Best bang for the buck? No. But it is fun to drive and highway rpms are spot on for this motor.
) with a discussion that solved my issue!
