Chrysler or AMC ?

[tblack]

I was hoping someone out there can solve a mystery for me. In 1987 Chrysler took over the Cherokee and shortly after the 4.0L 6cylinder engine appeared. Is that engine still made by AMC or is it a Chrysler product?

[glennco1]

Well, I'm gonna try to get this right, but we'll see. This motor was originally a Ford motor found in mustangs in the 60s. Much like everything else, AMC stole the design and continued to use it until Chrysler bought the company in the early '80s. The 4.0 was an evolution of the 258. I believe they are nearly identical. The 4.0 is the same block as the 258, but has a shorter stroke if I remember properly.

Is that right?

[tblack]

You are probably right. I think it's a FO-AM-CHY. The joint effort of everyone but GM. But in the mid-eighties, even GM got in on the act and sold the "Dauntless" 2.8L V-6 which turned out to be such a disappointment, AMC returned to the 258-straight 6 design and called it the 242CID engine just before the Chrysler came on the scene and it became the famous and best 4.0. I just get confused with all the collaberating. I think everyone had their fingers in this pie.
tb

[scrap_iron]

This engine debuted as the "Typhoon 6" in 1964 in the AMC Classic with a 232 cubic inch displacement. It was later offered in 1972 as a 258 cid, and then as the mainstay Jeep engine at 242 cid (4.0L). The heads changed slightly, but it has been the same basic design for many years.
I'll have to check on the connection to ford, I thought that that it had a 4 main bearing design and I believe the AMC/Jeep design is 7. Chrysler basically just bought AMC/Jeep from Renault when it was having financial problems and didn't screw with the 4.0L design too much (to their credit).

[tblack]

Excellent Scrapiron! Thanks for clearing that up. I have never had it explained that clearly.
tb