The I6 Sacred Cow

I thought the reason they stretched the front was for the 304??? I've always liked the little V6 myself.

 

Nope, supposedly the V8 will fit without any stretching.

 

No, the 232, 258 and 304 V8 were introduced in CJs and COmmandos for the 1972 model year. AMC put their engines (258, 304 and 360) in the trucks and Wagoneer a year earlier though, in 1971.

 

I had a '51 Chevy with the 216 I6 and still have a '53 Buick with the I8.
In both, passengers have told me that the motor had died at a light, "nope, It's fine"...
I need to change the head gasket on the Buick sometime soon, I'll let you know what the head weighs.

 

I'll give them longevity, both with respect to manufacture (only exceeded by the small block Chevy) and durability. A lot of low end torque makes use in a Jeep a good stock application.

Power to weight-maybe not so good.

If we use gross hp (apples to apples), and all in stock form:

the 225 V6 @ 160 hp for 414 lbs gives 2.59 lbs/hp
the 258 I6 @ 200 hp for 484 lbs gives 2.42 lbs/hp
the 4.3 Chevy V6 @ 200 hp for 425 lbs gives 2.13 lbs/hp
an all iron, run-of-the-mill 350 Chevy at 255 hp at 535 lbs or 2.10 lbs/hp

Then there is the 381 sbc in my 3B which is conservatively at 1.11 lbs/hp

Does that give the I6 any advantage in power to weight? I don't really think so.

That and a V6/V8 is a LOT more compact package with a lot of avantage in induction options. Personally, I would probably not ever rebuild a 258 or 4.0-it would be replaced by a small block V8 something-as long as Chevy made it.

 

Gets my vote

Later models had a two stage, two speed (you shifted gears) supercharger even..



Maybe a bit much for a rock rig, probably be better suited for something line this.....................

 

I'm a little confused as to why this topic is even in this Forum and I've never heard anyone suggest using a straight 6 in an Early CJ instead of a V6 or V8. Maybe I haven't been paying attention?

 

They make great ballast and are always worth at least 7 cents a pound in scrap. It is the same as Ford vs. Chevy. Some people like them just bcause they don't know any better. There are soooo many better engines out there. I am not a fan of any AMC motor however.

 

I like the 7 main bearing design of most of them (258, 4.0L and 300 Ford). The crankshaft support is fantastic. Makes for a truly strong lower end.

 

Sort of my sentiments also but-----



my wheeling buddy for the last 35 years sold a FJ 40 with a 4 spd and 307 sbc and bought a new 96 XJ. To say I thought that was a mistake would be an extreme understatement. However, 17 years and close to 300k later, I have to say that was a pretty good piece of engineering for its intended purpose. I still fail to see any merit in any performance upgrades to it. Money would be much better spent on a V8 rather than a similar amount of funds on a stroker kit.

 

Oops - yes.

But that's not the only error in my posts. :?

 

Yeah, the Kaiser 230 "Tornado" I-6 does have a reputation for being a boat anchor.

First US overhead cam after WWII, supposedly smooth and efficient, with good torque, but it was known for jumping the timing chain. My Kaiser M-715 had one and in the end I gave up on it.

 

You can add Jaguar, BMW, Mercedes, Volvo, Toyota, and Nissan to the list of automotive companies who make/made legendary I6 motors.

 

:iagree:

 

Say John, Where did you come up with those engine weights ?
That's some valuable data but I think it's deficient without including in the weight of stock engine accessories.
Including the fan through bellhousing, plus clutch.

Also if weight to HP becomes the most important concern then the 2 cycle engines will rule.
So I prefer to compare various engine designs via max torque vs. displacement.
That gives one input concerning an engines overall design efficiency.
Then among many other concerns the RPM at maximum torque helps to indicate an engines optimum potential application.