Hosted by Moses Ludel
The Jeep inline six stroker motor has been a popular topic! In this HD vlog, hear Moses Ludel describe a Hewes Performance Machine engine that now powers a 1998 Jeep XJ Cherokee. Hear Moses’ comments on this engine build and how the Jeep performs! (See the build components list below. Also see the 6-part HD video interview series with Tony Hewes, available exclusively at the 4WD Mechanix Video Network!)
There are many configurations for the Jeep inline six stroker motor. At a 0.030″ (typical cleanup) rebore with the 4.2L/258 crankshaft, the new displacement is 4.6L. (A stock 4.0L bore with a 258 crankshaft equals 4.5L; a 0.060″ rebore with 258 crankshaft equals a 4.7L displacement for this engine buildup.) With the special attention to the cylinder head porting, exhaust upgrades, balancing and use of the 24-pound Ford 5.0L V-8 injectors (Ford part #F1TE-D5A or Bosch 280 150 947), this engine should dyne around 260 horsepower with the 8.7:1 compression ratio and CompCams 252 grind camshaft.
For Jeep use, the real success story with the 4.6L stroker six is the torque output and torque curve. Torque rises far more quickly than a stock 4.0L and should exceed peak 4.0L torque by at least 50 ft-lbs! Most of the torque comes in by 2,000 rpm, and this improves the real world driving feel and trail crawl performance. Torque continues to climb to a peak in the 300-340 ft-lbs range by 3,200 rpm—depending upon the build. On the engine tested, the moderate compression ratio and camshaft, balancing, head porting and exceptional parts quality make this a “longevity” engine, clearly built for 250,000 miles of trouble-free Jeep 4WD service!
Footnote: This engine runs the stock 4.0L Jeep multi-point port injector rail with 5.0L Ford replacement injectors fitted in place of OEM injectors. This modification meets potential fuel demands of a 4.6L stroker—without adversely affecting drivability or tailpipe emissions…Owner added a HESCO thermostat housing and water pump to enhance coolant flow with a Griffin high performance radiator.
Key Parts and Machining for This Stroker 4.6L Inline Six:
Cam bearings: Sealed Power
Rods: Stock 4.0L from 1998 XJ engine core
Camshaft: CompCams 252 grind with lifter (flat tappet) kit
Crankshaft: Stock 4.2L/258 core, fully machined and balanced (snout length machined for serpentine pulley)
Hard exhaust valve (replacement) seats and high performance valves
Full gasket set
Brass freeze plugs
Harmonic balancer: stock, balanced with other reciprocating parts
Main bearings: King 0.010” undersize for machined crankshaft
Rod bearings: King 0.010” undersize for machined crankshaft
Oil pump: Melling high volume with new pickup screen
Pistons: Forged IC944 0.030” oversize with pins
Piston rings: Hastings 667 in 0.030” oversize
Timing chain set: Cloyes performance
ARP rod bolts for 4.0L connecting rods
Silicone bronze valve guide liners
CompCams new valve springs
Key Machining Operations
Hot tank block, head and reusable parts
Align hone main bearing saddles with main caps
Deck block for straightness and establishing correct piston crown height
Bore and hone to 0.030” oversize finish
Regrind 4.2L/258 crankshaft core
Balance all reciprocating engine parts
Fit pistons and pins to rods
Fit new “hard” exhaust valve seats
Machine and fit silicone bronze valve guides
Magnaflux all castings
Align and hone stock Jeep 4.0L rods
R&R cam bearings
Surface cylinder head
Set valve stem heights (for correct lifter plunger heights)
Complete “valve job” with machined valve seats, intake valves and spring seats
Four hours of cylinder head porting and header port match
Assemble long block to proper tolerances and fit
