I'm curious about the history of the 4.0 engine. I know it's based on an engine AMC introduced in 1964 (and powered a bunch of Gremlins a while later), but at some point AMC (or Nash) took a clean sheet of paper and designed a new engine that eventually evolved into our wonderful 4.0.
Does anyone know when that was and anything about the orginal engine?
Jeff DeWitt
are you asking about the 4.2 liter (258 cubic inch) engine or the 4.0 liter engine? I may be wrong here, but I thought the 4.0 liter was designed by Chrysler long after both AMC and Nash were out of business.
The 258 may have ancestry in Gremlins, but I don't think the 4.0 does. The 4.0 debuted in Wranglers (YJ's) in 1991. Chrysler Corp. acquired American Motors in 1987. Nash merged with Hudson in the mid-Fifties to form American Motors.
The 4.0 Power Tech Six was designed by AMC. It was designed from the beginning for the XJ, the down-sized Cherokee and Wagoneer Limited. It shared a number of components with the 2.5 four. It was introduced in the 1987 XJ just about the time Chrysler took over AMC, but they did not design the 4.0.
Dick
Isn't Bill Google?
twaldron did pass the time by typing:
wget www.*.* -r
But do you actually want _all_ of the web on your hard drive... think about it... :)
anyone remember g***se.cx >_<
*WARNING* althouth the domain is down google at your own risk. That site was not safe for carbon-based life forms.
If you Google on this you'll find that it is widely believed by posters that the 4.0L/242ci is simply an updated 258ci and that the 2.5L I4 was simply a 258 with 2 cylinders lopped off.
But many sites that bothered to look things up claim that the 2.5L was pretty much designed from the ground up and that the 4.0L is mostly based upon the engineering for the 2.5L engine, although obviously some
258ci parts will fit (or, /mostly/ fit in the case of heads) on the 4.0L block. See:The 258ci was, of course, simply a stroked 232 block (anyone want a free
232 engine? Come and get it). See:Ah! This sounds like what I remember reading, but the link is down right now. Google Cache has it at:
Or Google the phrase _"closer relation was the fuel injected I-4"_
Jeff DeWitt wrote:
Historical perspective. The OP asked about the history of the 4.0L and thought that it had been designed on a "fresh sheet of paper". I was trying to cover all the bases and show that the 2.5L was the one designed from the ground up and the 4.0L was based on that engineering work. And that neither is very close kin to the 232/258.
L.W.(ßill) Hughes III wrote:
Close enough that the crank can be swapped over making the 4.0 a stroker....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT'sLee Ayrt>
I remember when that 4cyl came out and I swear they were saying at the time that it was basically a 258/232 with two cylinders cut off and a revised head. It wasn't JUST a 258/232 with two cylinders lopped off, but basically that is what they did. The 4.0 was basically the same engine with the two cylinders put back on.
Keep in mind when AMC designed the 4cyl they weren't exactly flush with cash, as much as they could they had to make do with what they had. If that wasn't the case how do you explain the Gremlin and the Spirit?
Seems to me that it's HIGHLY unlikely they would have designed a totally new engine that would bolt up just like the old one AND would have really major parts like the crankshaft interchangeable with the old one.
The independents had to do some VERY creative things to survive as long as they did.
I never heard of a stroker 4.0, cool idea, I'd love to build one, then I can REALLY piss off the Mustang crowd with my Cherokee
Jeff DeWitt
Lee Ayrt>
The 4.0 uses different castings from the 232/258, however the design was constrained by the fact it had to run on the same transfer line. The tooling is shared between the two designs. Given this sharing, it is doubtful that there was any truly "blank sheet" of paper. As an aside, the age of this tooling may be what finally leads to the discontinuation of the Jeep I-6.
-- jeff
Jeff, Some links after a little google search.
Luck, Brian
Clifford Engineering, JRE, and Hesco all seem to be popular sources...
Bulletsnbrains proclaimed:
A grandfathers axe job though surely ?
( this is my grandfather's axe - my dad changed the head, and I've changed the handle).
Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ
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