Why did AMC use the GM 2.8 V6 when they had their own inline 6 that found its way into the XJs in the mid-eighties?
Why did AMC use the GM 2.8 V6 when they had their own inline 6 that found its way into the XJs in the mid-eighties?
They didn't have the 4.0 until '87.
In reply to Russian Warship, Go Berkeley Yourself :
But they did still have AN inline six, no?
In reply to Pete. (l33t FS) :
They did -- the 232, which seems to have been developed into the 4.0. Maybe it was too expensive to develop in time for the XJ. That would be consistent with AMC's operations.
AMC had the 258 / 4.2 I6 in those years, which they were using in other Jeeps. The 232 was gone by then, I think. I'm guessing there was some development or perceived economy reason why they imported a smaller 6 cylinder to use instead of just using their own. They did use their own 2.5 liter 4 cylinder as the base engine.
Pete. (l33t FS) said:In reply to Russian Warship, Go Berkeley Yourself :
But they did still have AN inline six, no?
One whose days were numbered. There was no point in working on fitting the leaky, wheezy Carburated 258 into the XJ when there were modern designs available. Unfortunately, those "modern" options were not very good choices. So AMC developed the 258 into the 4.0 in a mere 26 months. But even then, the 4.0 didn't reach its legendary status until Chrysler killed off the Renix FI system and developed the 4.0 H.O.
What's a bit crazy is how the 258 hung on until 1990 in the Wrangler. I would have figured that Chrysler would have killed that motor off and just offered the 4.0 (actually not sure why AMC didn't do that themselves, probably production volume limitations with the 4.0 so they needed an alternative engine?) as soon as possible.
I think the 2.8 was really just a stop gap before the AMC 2.5 inline-four was ready for prime time. I think the power numbers are very similar between the two and mileage was probably better with the 2.5. It seems like a very good engine that was unfortunately about a decade too late; I think it would have been great in the Pacer, Gremlin, and Spirit as a mileage/low-cost motor. This motor and an overdrive five-speed in a Spirit hatchback seems like a pretty nice little package that just wasn't around at the same time.
AMC was shakey at the time. I wouldn't be surprised to find they could buy epa compliant 2.8s cheaper than building them.
If they were really smart they would have used the crank and rods from the 258 and put them into the 4.0HO. Built a 4.7l stroker (258 bits plus 0.060" over) in my shop for a YJ Wrangler and it was nuts.
preach (dudeist priest) said:If they were really smart they would have used the crank and rods from the 258 and put them into the 4.0HO. Built a 4.7l stroker (258 bits plus 0.060" over) in my shop for a YJ Wrangler and it was nuts.
AMC's Mexican arm did that. Ref: AMC 282 Wikipedia Page
Russian Warship, Go Berkeley Yourself said:Pete. (l33t FS) said:In reply to Russian Warship, Go Berkeley Yourself :
But they did still have AN inline six, no?
One whose days were numbered. There was no point in working on fitting the leaky, wheezy Carburated 258 into the XJ when there were modern designs available. Unfortunately, those "modern" options were not very good choices. So AMC developed the 258 into the 4.0 in a mere 26 months. But even then, the 4.0 didn't reach its legendary status until Chrysler killed off the Renix FI system and developed the 4.0 H.O.
And then Chrysler started updating the guts of the 4.0 around the OBDII change and ruined it. See 96+ 4.0s with piston skirts that sometimes just break for no reason and the 99/2000+ 0331 heads where 20 - 30% of them seem to crack on top side totally unprovoked (and inattentive owners end up with a scrap engine, as the crack pukes coolant directly into the oil, so many lost the main bearings before the owner noticed the problem).
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