94 Grand Cherokee 5.2 L - More Grunt........

Full time Quadra Trac, Tow package with Tranny cooler, 3.93 Rear.
Recently bought a Trailer (5600lbs GVRW)and am considering beefing up
the GC instead of buying a Ram 2500 Cummins........ (nice, but $$$) GC
pulls ok, but I sweat profusely on the steep hills. Paranoid with the
318 after 2 major engine disasters. (main bearing meltdown, valve
spring failure)

a) build up a 360 on the bench, or a crate motor
will a 360 swap in nicely? build up suggestions?
b) add power to the 318.... (already have K&N kit, MSD ign, Flowmaster
exhaust)
suggestions?

My hobby car is a '71 Mustang, I know precious little about whats
available for the Grand Cherokee.

Many thanks for any help......

Steve

 

??! How'd you manage that on one of the stoutest V8s ever built???

DS

 

well i have checked part numbers for the 5.9 and 5.2 and all
sensors/injectors and such are the same so it's a direct bolt in as far as
i can see untill someone tells me different
i would go to a stiffer camshaft

 

How'd I do it? Sumpthing called an "oil flush"....... If your pan has
any sludge in it, this so called cleansing can actually free up
particles and circulate them around the block. One of the journals to
the mains got plugged and the bearing burned up... rod broke as well.
I bought a short block and had a "professional" inspect the heads and
re-install. They never would give me a straight answer on if the
valve that went was from the same cylinder that busted the rod.... but
they did do a complete valve job when they fixed it at 50% off.
So... even though I know the 318 to be solid, and it should be, now
that it is thoroughly sorted, I am still paranoid when I head into the
mountains...

Which Cam is recommended for the 360? Does the 360 need to be a later
model for the sensors to plug in? and mounts to align? or can I use an
earlier block? how does the cost of a crate compare to an equivalent
build up?

How about a better cam for the 318? Would that make enough of a
difference over stock? (emissions are pretty stingent here in BC)

Thanks again!
Steve

 

Don't be. My 318 has 435,000 miles on it. 240,000 of thise miles since a
"freshening" with new rings and bearings, and I'd do anything with it
today that I've ever done (tow a trailer over Wolf Creek Pass, wind it
out to the top of 1st and 2nd gear on an entrance ramp.... you name it).

Depends on what you want to do, but if you want to leave it
computer-controlled, emissions legal, etc. etc. then you only have a
couple of choices. The stock cam is decent, and Mopar Performance sells
a CARB-legal cam for the 5.9 (360) used in Ram trucks. The Grand
Cherokee probably uses a different computer code, but it would probably
be able to keep up with the MP cam.

It needs to be a Magnum variant- very common engine in Rams, Dakotas,
and Durangos from 1993 until 2002. Magnum 360s come with two sets of
engine mount bosses- the "pan rail" bosses used in Ram
trucks/Durangos/Dakotas, and the "ear" bosses used in earlier 360
applications. If the Grand Cherokee uses the pan rail bosses, your fine.
If it uses the "ear" bosses you'll have to modify the driver's side
engine mount as the ears on a 360 are slightly different than a 318.

Also be aware that the 360 is externally balanced and the 318 is
internally balanced, so a 360 needs a different harmonic balancer and
torque convertor (or weighted flexplate). The 360 uses a different oil
pan also, so if the Grand Cherokee doesn't use the same shape oil pan as
a Durango, Ram, or Dakota, you'll have to locate one from the VERY rare
5.9L Grand Cherokee that was sold for 1 year.

 

well if i had the cash i would go with a crate motor since it has a 3/36
warranty
but a cam should be selected with what you will be towing and the rear
axle gear ratio in mind

 

Ooh, yeah, ouch, those "engine enema" preparations don't discriminate --
they'll finish-off a Mopar as easily as a Ford, GM, Honda or Mercedes
engine. They are a singularly bad idea. Typically what happens is the oil
filter quickly loads up with crap, the bypass opens and additional crap
gets sent directly to the bearings. Presto, instant spun bearing and/or
worse. There are very few cases in which any kind of crankcase flush is
warranted, and only one specific kind of case (coolant in oil) in which
these butyl cellosolve based flushes are warranted. And even then, they
must never be used in the "Jest dump it in, run 'er for five minutes, and
drain!" manner suggested on the can. You have to drain the old oil,
install a new oil filter, put in new oil with the flushing compound, etc.

You shouldn't be. It was the engine "flush", not the engine, that caused
the failure.

I think I'd be tempted to pick up a low-miles 5.9 engine with torque
converter (as Steve mentioned, the 360/5.9 is externally balanced, while
the 318/5.2 is internally balanced) out of a late-model/low-miles wrecked
Jeep. Hit www.car-part.com .

DS

 

Daniel J. Stern wrote:

The only fly in the ointment being that 5.9 Jeeps were rare, rare, RARE.
It would be simple to finda Ram, Dakota, or Durango 5.9, but then the
oil pan, mounting points, and other details might be different. The 318
engine controller can adapt enough to run a stock 5.9 (a friend of mine
has done this in a Dakota) but it doesn't have enough adaptability to do
things like run a 5.9 with the MP cam, headers, etc. unless you match it
with higher flow fuel injectors. It can be done, but you gotta know what
you're doing.

 

Thank Guys,

I am amazed (now that I have lived through this oil flush disaster)
how few people know how risky it is. EVERY time I get a change done,
some fresh graduate of The University of Mr. Lubeology not only tries
to sell me one, but insists upon debating the efficacy of the
procedure after I decline the treatment.... sheesh!
The new 360 is NOT recommended for towing (thank's Tom)....... cooling
issues in the Grand Cherokee, not enough front surface area to
properly cool, etc.
The consensus seems to be that the 318 is a strong and proven engine,
I think I will run it as is for a few trips and see how she goes. I
have had some cooling concerns in the past as well. I'll tow
cautiously, if I have issues then I may have to get the Ram 2500 /
Cummins. Although I have grown used to not having any vehicle
payments.
Although the supercharger, header treatment for the GC sounds
interesting.....

Steve

 

Not according to Hollander's. Apparently, the engines were commonized by
the time the 5.9 (VIN code Z) was first installed in Jeeps in '98. A check
of www.car-part.com , which draws its interchangeability info from
Hollander, shows VIN-Z engines going in Durangos, Dakotas, Rams...and
Jeeps. So the field of available direct-swap engines is sufficiently
large.

I do not buy the claim that the 5.9 is not recommended for towing on
account of inadequate cooling -- donno where that came from, but it's
easy to add more than enough extra cooling capacity with radiator
upgrades, and there's *gobs* of air intake space on a Grand Cherokee.

DS

 

That's good info... assuming it's correct with respect to all the little
details

Nor do I. The claim *probably* is an ougtrowth of the fact that the
factory issued 5.9 in a Grand Cherokee was *not* rated for towing. It
was very much a "sport truck" sort of installation, without all the
other things (cooling, gear ratios, etc.) needed to make it a tow
package.Its claim to fame at the time was that it was the "quickest SUV
on the planet." But none of that in any way shape or form suggests that
one couldn't build a towing monster out of a Grand Cherokee using the
5.9 as the starting point.