AMC L6 Replace or Update?

I live in Denver, Colorado. So would replacing the crank on my 232 make it essentially a 258? Seems I read that somewhere before... OR should I just break down and buy a used engine and dump my 232?

 

http://www.colorado4x4.org/vbb/showthread.php?t=41505

keep checking here as they come up fairly often.
i would post in their wtb section and i bet you could get one in good running condition pretty quick.

chris

 

Crank, yeah, and the rods too. You can't just swap the crank, or the pistons won't match the deck height. The bore is the same for the 232 and 258.

Anyway, I'm not sure you could put a 258 crank and rods in your 232 for much less than you could buy a used 258.

 

Not to be an a$$ but lets back up a bit. Before you go out buying another motor check your gearing first. As someone stated earlier its free. Next go through and check the basics, plugs, cap, rotor, points, wires, timing and carb adjustments. Worst case put all the basics on (cap, rotor, plugs and wires) and take it to a reputable shop to get it dialed in.I have purchased alot of used vehicles over the years and these are always among the first things I do. You would be amazed at how many times I've found things misadjusted and hindering performance (almost everytime). A little tweek here and there could make a big differance. Just my two.

 

Oh, that is definately on my list today, I'm not going to buy a new engine or new anything just yet, I'm trying to get ideas as to some options I have for this.

I've gone through the plugs quite a few times and they look pretty good actually and I've just ordered the GM HEI (from a guy that has a pretty good reputation on another board, JMJEEPS) so I expect to see some improvement there but I never thought of taking the whole deal into a shop, didn't know there were any that did piecemeal stuff like that.

 

Hey, I just got a bead on someone who want $250.00 for their 258 from a local Colorado 4x4 board (thanks to the person who sent me that by the way). He says it has 80,000 miles but it's from an 86 CJ7 - will this work in my 72 as a fairly easy swap for my 232?

 

Yeah, it'll work with a few caveats. It will bolt up to your existing bellhousing and fit your existing motor mounts. If it uses a serpentine belt instead of v-belts, you'll need to get all of the accessories with it. If it has power steering, it will make the PS changeover just that much easier. It will have a 2V Carter BBD (computer controlled?) carburetor - very troublesome - and Motorcraft electronic ignition. You'll have to choose between the Motorcraft and GM ignition. If you already have the Motorcraft, there's not much reason to change to the HEI.

The big changes in the AMC inline 6s came in 1971 and 1981. The pre-71 motors are not interchangeable with the 71-on motors. The 258 was introduced in 1971. By 1981, the 232 had been dropped. The light-weight 258 was introduced in 1981 with a lighter block casting, a lighter crankshaft, lighter intake and exhaust manifolds, a 2V carburetor for all 258s, and a plastic valve cover. (The plastic valve cover was a disaster). The light-weight engine can be swapped with the 71-80 engines, but you may find some minor differences, so get as much of the engine and its accessories as you can.

BTW 80K is not high mileage for a 258 - they last a long time. If you are interested, check that the engine has good oil pressure and good and even compression. $250 seems about right for a good used 258.

 

I think that if it was me with a '72 I would swap in a Chevy V8. Common, cheap, efficient in a Jeep, fairly straightforward swap, and more power.
You could also swap in a 258, and upgrade it with some of the products from these guys http://www.hesco.us
I am running the MOPAR MPI kit that they sell and love it.

Another consideration would be a later model Jeep 4.0 swap, a good source of info can be found in the 4.0 swap forum at http://www.cjoffroad.com