Video Interview: Jeep 4.6L Stroker Inline Six Camshaft Choices!
This series includes six HD video interviews with Tony Hewes...In addition to the video on this page, you will find the other five HD videos at the
'4WD Tech How-to Channel'
In this HD Video, Tony Hewes and Moses
Ludel compare 4.0L/4.6L camshaft choices for multipurpose trail-and-street use, fuel efficiency and
The 4.0L valvetrain
(above) is typical of the later AMC 4.2L/258 designs. This a common engine for modern rebuilders.
Builder choices are around compression ratios and camshaft design. Below is a drawing of the earlier AMC version of
the 232/258 engine with its rocker shaft assembly and rocker arms. The later 232/258 (4.2L) and 4.0L use a lighter,
stamped steel rocker arm system with bolt-down pivots and strap bridges.
Earlier 232/258 AMC inline six with a
rocker shaft and arm assembly.
Often, a quality Jeep
4.0L engine build falls short of expectation due to the wrong camshaft choice or too high compression. It is easy
to think "big" when building a 4.0L engine into a 4.6L stroker. However, trail use and rock crawling are a far cry
from desert racing or mud bogging.
In this short, critical HD video segment
with Tony Hewes, Moses Ludel and Tony share their views of camshaft choices. The targets are a 4.6L inline six
stroker motor and other Jeep inline six-cylinder applications intended for off-pavement trail running and street
There are solid reasons for going "mild" with the camshaft choice if you
truly want rock-crawling, stump-pulling low end torque. Low-end torque also adds to optimal fuel efficiency...Watch
the video and hear Tony and Moses compare details!
Note—Here are links to CompCams'
252H grind, discussed in the video...This camshaft has performed and tested well in pre-coil pack 4.0L stroker
builds. We are currently considering whether or not this is the optimal camshaft for 1999-up TJ Wrangler
and 2000-up XJ Cherokee builds with the late coil-pack ignition and cylinder head redesign. Stay tuned for our
findings about camshaft grinds and tuning for the later coil pack engines:
Here are camshaft choice and tuning
comments from a Moses Ludel topic post at the 4WD Mechanix
'Tech and Travel' Forums. Join the forums and participate in these
"At the magazine, building a Jeep inline 4.0L six with a 4.2L
crankshaft (stroker motor) is very popular. Tony Hewes (Hewes Performance, Reno, Nevada) and I did a
series of HD videos and shared our favorite components for a 4.6L (0.030" overbore with the 4.2L crankshaft)
stroker motor build for combined street and trail use.
we have received a lot of feedback and continue to address the tuning and camshaft requirements of these
engines. From our testing, the pre-coil pack (1998 TJ and older 4.0L) engines with older style
injectors do very well with Ford
5.0L V-8 24-pound
injectors—no emission quirks, "Engine Check" lights or other issues when tuned correctly. Ford
part number F1TE-D5A or Bosch number 280 150 947 is the specific injector type. These engines work well with
the 252H CompCams grind camshaft and 8.7:1 compression.
TJ Wrangler and 2000-2001 Cherokee engines with coil-pack ignition have square injector connector
plugs. For these engines, stroker builders use the Dodge Ram 5.9L V-8 injectors listed for 2000-up with coil
pack. This is the injector that HESCO calls a "24-pound/hour”. HESCO supplies rebuilt GB injectors,
although new Mopar OEM part numbers are available. This injector also crosses over to the aftermarket Bosch
Fuel Injector #62005 offered at Summit Racing for a significant price per injector.
Here is the GB
website: http://www.gbreman.com/index.html. The 5.9L Ram truck V-8
application is the GB812-12132 injectors for engines to 2003.
I researched further
and came up with the OEM 5.9L Mopar V-8 injector part number: 53031740AA. (I used 2001 as a clear year
for coil-pack and square injector plug.) This OEM Mopar injector is 23.61 pound/hour rated at 43.5
PSI. This is a "high impedance" injector design with a square plug socket.
The OEM injector
on a coil-pack engine rates 22.5 pounds/hour at 49.0 PSI fuel pressure, which may work okay on a coil
pack stroker engine unless the cylinder head, compression or camshaft/head combination is an issue for the
PCM. Fuel rail pressure of 49.2 +/- 2 PSI should be confirmed by factory testing
Click here for
an instructional PDF for running fuel rail pressure tests on Jeep MPI. This is the 1997-up XJ Cherokee and TJ
Wrangler type with fuel tank mounted pressure regulator and single-rail injection.
In the late '90s, my engineer friends, Jeep performance
enthusiasts at Mopar, were talking about 5.9L Mopar V-8 injectors for 4.0L/4.6L stroker engine
builds. This has apparently been a route to go, with a 24-pound/hour injector
I researched the Jeep ZJ Grand Cherokee 5.2L/5.9L V-8 injectors
from the mid-‘90s: 1995 Jeep 5.2 ZJ/Dodge 5.9L V-8 injectors are Part #53030262 and rated to flow
24.6-pound/hour at 39 PSI. By 1996, the Jeep V-8 injectors rated 23.2 pounds at 49 PSI. The 1995 Mopar
injectors (24.6#/hour @ 39 PSI) could be an alternative to the 302 Ford injectors for a stroker build in
a 1991-95 Jeep 4.0L MPI chassis application if the engine demands that kind of flow.
Summing it up, if GB is
accurate, using the right injector cores and parts for this application, HESCO is marketing a “24-pound/hour @
43.5 PSI injector for a stroker inline six. A caution here is that the '97-up Jeep TJ Wrangler and XJ Cherokee
have a 49.2 +/- 5 PSI rail pressure. Flow could be higher than 24 pounds/hour at this 49.2 +/- 5 PSI rail
If the GB812-12132 injector is okay for a coil pack later engine with the later cylinder head casting, the
GB812-12132 square plug injector would be the choice for later coil-pack engines. There are a number of
sources for these GB injectors.
We're still testing the
CompCams 252H camshaft in a later 4.0L (1999-up TJ Wrangler/2000-up XJ Cherokee) engine with the
redesigned head and coil pack ignition. Tony and I will update on these late 4.0L/stroker engines. The
pre-'99 stroker engines and stock PCMs have worked well with this camshaft grind. We're consulting
with CompCams about a possible new grind for later coil-pack ignition stroker engines.
The 1997-up TJ Wrangler
and Cherokees with the tank-mounted fuel regulator use higher fuel pump/line pressure. I would stick with Mopar
53030262 or Ford 302 V-8 type injectors* on the 1997-98 TJ Wranglers and Cherokees through 1999 (without the
coil pack system).
24-pound 302 5.0L V-8 injectors fit the pre-coil pack engines; coil pack engine injectors have a square plug
are some useful links and comments at the magazine site:
[I detail pressure ratings and designs for Jeep engines equipped with MPI/EFI. 1997-up single rail systems
with tank-mounted pressure regulator are higher pressure, running rail/injector pressures typically around
49.2 PSI +/- 2 PSI. This includes the coil pack engines with square wire plug injectors.]
http://www.4wdmechanix.com/Jeep-TBI-&-MPI-Advanced-Troubleshooting.html [Overview of
OEM tuning methods and factory diagnostic tools required.]
http://www.4wdmechanix.com/Vlog-Why-Build-a-Jeep-4.6L-Stroker-Inline-Six.html [Video vlog
useful third-party website for every popular OEM fuel injector’s flow ratings.]
http://www.4wdmechanix.com/Vlog-Road-Testing-Jeep-4.6L-Stroker-Inline-Six.html [My video
comments on Brent H.’s Cherokee 4.6L build and its drivability. This is a video vlog plus a list of key
components used in this Hewes Performance buildup for a 1998 Jeep XJ Cherokee chassis.]
Of course, there’s also the entire 4.6L Tony Hewes interview series of HD videos,
six individual videos covering the build of a stroker inline six-cylinder Jeep engine!"
Want quality automotive machine work or a precision engine
build-up? See the Hewes Performance Machine website at: