ADVICE: Jeep 4.2L vs 4.0L
Gordon Boyes
I was helping a friend of mine look over a '90 Wrangler last night.
I expected it would have the 4.0L FI engine however it had the 4.2
(carb) that was not replaced until 1991. I have some experience with
the 4.0L in the Cherokee (seems like everyone I know has one). I know
it is a good engine. The 4.2L felt a little rough and less resposive
than the 4.0L over 3000 rpms. Of course my friend did not notice this
because she is a more conservative driver than I. If it had the 4.L
FI I'd tell her to make the owner an offer.
What opinions do people have on the 4.2L? Would she be better trying
to find a '91 or newer? Maybe even a 4cyl?
FYI: The '90 had 72,000 miles...
Please reply via email.
Thanks for any advice,
-Gordon
email: boyes...@bah.com
Terry Howe
gas milage. Some might argue the 4.2 has a better torque curve
for offroad, but that is probably its only advantage. I would take
the 4.0L first, the 4.2L second, and any 4 cylinder after that.
The 4.0L and the 4.2L are very similar engines, but FI makes all
the difference.
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+----------------------------------------------------------------------+
| Terry L. Howe '81 CJ-7 te...@apache.att.com |
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Davin Lim
>The 4.0 beats the 4.2 in every way. More HP, more torque, and better
>milage. The 4.0 is about the best thing going in its class . The 4.0
>in a Cherokee is rated about 190 HP, but the 4.2 is down around 155 or
>so.
>Unless the deal is SUPERsweet, I'd hold out for a 1991 with 4.0 Hi
>Output
Just another note, in a Wrangler, the 4.0 delivers slightly less HP
than in the Cherokee, 185 (180?) is the number that comes to mind. The
difference is supposed to be due to the slightly more restrictive exhaust.
Still, it's a great engine. In addition to the power advantage, it has
the distinct advantage of not having to know black magic to tune the
carburetor - as it doesn't have one. No way would I get the 4.2 if the
4.0 was at all affordable.
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...................................................
* Davin Lim *
* mailto:li...@arraytech.com -- Boulder, Colorado. *
Steve
milage. The 4.0 is about the best thing going in its class . The 4.0
in a Cherokee is rated about 190 HP, but the 4.2 is down around 155 or
so.
Unless the deal is SUPERsweet, I'd hold out for a 1991 with 4.0 Hi
Output
Steve A. Porter spo...@mail.Traveller.COM
RGSer
choice is clear for anything less than off-road grunt: The 4.0L is great-
the best engine EVER to reside in a factory Jeep. The only area that the
4.2L has a slight advantage is below about 500rpm- simply more apparent
torque. The 4.0L tends to fade at the bottom. Oh yes, and what do you do
when the F.I. quits on the Ershim? For the young lady who is going to get
the Jeep, I doubt whether she will wind up being a hard-core rock crawler-
so there is NO advantage to the 4.2L. Jeff
Steve
rg...@aol.com (RGSer) writes:
> The 4.0L tends to fade at the bottom.
One question: Can't that be fixed with headers or a Jacobs Ignition
system?
Steve A. Porter spo...@mail.Traveller.COM
Unknown
The 4.2 can be upgraded with a MPI unit. Two are sold by Hesco (As is one TBI). They
give the 4.2 equitable performance. Runs around $1700.
Just so you can see if the deal you are getting is really that sweet.
Scott Norman
: The 4.0L is great-
: the best engine EVER to reside in a factory Jeep. The only area that the
I dunno, I kinda like the 360V8 in my '74 J-10, considering I
chucked/swapped for other gear another one because I couldn't break the
original :-}
--
Scott Norman //\\ //||Just another guy trying to ||Box 2394, Stn. C
aka Acid // \\ // ||get ahead in the world. Too||St. John's, NF
=============// \\// ||bad the world jumped the ||Canada
||start on me. ||A1C 6E7
Joe Chew
along with the fuel injection and control systems, onto the 4.2 block.
Never done it, never seen it done. Some modification required, Anacin
not included. Dunno how this compares in finance and headaches to
just dropping a complete 4.0 into the older vehicle.
(Is the 4.0 "High Output" better than the regular 4.0, or did they
just figure out they'd sell faster with an extra nameplate?)
Moses Ludel's _The Jeep Owner's Bible_ (Stackpole Books) has a lot of
information on lineages, characteristics, and upgrade paths for Jeep
engines. Highly recommended even if your friend isn't a gearhead and
just wants to buy a vehicle and drive it around.
Mind you, most of the carbureted engines of the post-smog era aren't
undriveable (there were a few real turkeys but I don't think any of
them ended up in Jeeps). They just aren't going to have either the
pounce for the ounce or the smoothness and reliabilty of either pre-
smog engines or truly modern ones with fuel injection and closed-loop
controls. Cars took a dramatic turn for the better over the mid-80s
as their engine controls began working by measurement and realtime
control instead of preset guesswork.
--Joe
Joe Chew
>Stackpole Books
Baah. Try Robert Bentley, 800/423-4595, allegedly
also available as Chrysler/Jeep part no. P5249431,
or ISBN 0-8376-0154-1 at bookstores.
The book taught me a thing or two, and that's hard --
not finding things I don't know, that is, but teaching
them to me. At $30 it's hardly a cheap book, but it
could recoup far, far more than your investment in terms
of lemons not purchased, parts not ruined, or boondocks
not towed out of.
Happy motoring,
--Joe
Unknown
I drive a 90 Wrangler with the 4.2L power plant. I have both regretted that decision
and then found a solution. I am installing the MPI kit from HESCO. This is supposed
to make the 4.2 a bit stronger than the 4.0 (just my .2 88^). The kit is about $1700
and would probably cost $300 to install. So figure if you are saving $2,000 over
an equvalent 91, then it is probably OK. If not go with the 91 or later 4.0, you just start
out a little bit ($2K *&^*@^^@_e^) ahead.
BTW, I am genuinly happy with my 1990....