AMC L6 Replace or Update?

I've been giving some consideration to replacing my AMC L6 232 in my 72 Jeep CJ5 but am unsure if it would be the best move. My Jeep is just so gutless! I think the gears are REALLY low and it's been great on the trails but I would like to use it on the road a bit more often.

What do you think about the manifold/carb upgrades they have that will turn the 1bbl 232 into a 4bbl 232? I've heard some good and bad so I figured I would put it out here and see what you all think.

I have no idea what my gear ratio is (and am not looking forward to counting teeth to find out) but I know my performance issue may just be a very low geared Jeep. For instance I start out in 2nd gear because my 1st (granny) gear is SO low that I rap the thing sky high if I run over 3-5 MPH in it.

I've had V6's before (and I know they are supposed to be LESS powerful than an L6) and they are absolutely great engines for what I want around town and even in the hills. But THIS L6 is worthless for around town (and REALLY worthless to get to my great 4X4 sites where I live in Colorado) because I can floor the puppy in 3rd gear going up the mountain on the highway trying to get to my offroad site and MAYBE do 45-50MPH.

Any suggestions at all on this? Should I break down and get a 258/304/340 etc?

 

options:

Unfortunately replacing the engine will not help the gearing issue. It does not matter what engine you have it will run the same RPM at the same speed unless you change the gears.

I decided to replace my 232 with a 258 to get more off-road torque. The one I acquired had a 2 barrel carb and I converted it to fuel injeciton. It will run 60 on the highway at about 2700 RPM. (4:56 gears, T-18a tranny 1:1 high gear). It seems to like the hills but I have never driven it on the highway in mountains.

 

So how do you convert to fuel injection instead of carb? I upgraded my carb from the 1bbl Carter to a 2bbl Weber and it helped a bit but I think FI would be better.

Also, what did you do to your 72 to combat the vapor lock issue, that darn fuel line runs right atop the engine. I thought of extending it elsewhere but was concerned that the pump wouldn't put enough PSI on the line to work properly.

 

1) check out www.megasquirt.info for the fuel injection system I used.

2) to do fuel injection you have to replace the stock pump with an electric one. I have not had any problems with vapor lock with my current set up.

I will warn you though that my Jeep in not even close to stock when if comes to fuel, ignition or electrical system.

For more info on the mods I have done checkout my home page.
http://www.hudsonhawk.net/jeep/jeepmain.htm

 

Have you checked your axles for any tags/stamps for gear ratio? You may not need to count teeth...

 

Actually, when you remove the cover look on the side of the ring gear. Somewere on the side there should be some information stamped in. Of which (depending on the brand of gears) it will have either the ratio or the gear tooth count. This will save you some time and headache. The 232 is a higher reving motor then the 258. It tends to build more power at the top end. Some iginition upgrades would be swaping in an HEI ignition, as for the weber IMO they are kind of crappy, I much prefer the MC 2100 swap instead. You could swap a 2 barrel manifold off of a 258 and install the 2100 carb. They seem to do a lot better offroad then the Webers, not only that they don't have the constant rich that the webers do. Just my two.

 

I think an ignition upgrade would be the best bang for the buck. HEI would help it rev higher faster and produce a lot more spark then the stock system.

 

How about a 258, with a 4.0 head, headers, HEI, and FI? That sounds like the nuts to me. Of course I already have the 258, HEI, and headers
Of course, if you want more grunt, drop a AMC V8 in there.

Although none of any of this will help(?) with the low gears. What about a five speed and keep the gears????

.02

High5

 

If it needs a rebuild tho - it might be more cost effective to go V8. I'd weigh both costs and your desire/ability to do a swap in that equation.

 

First off I have to say THANK YOU - THANK YOU - THANK YOU, it is so generous of you all to be so willing to help wanna-be Jeep upgraders like me!

I'm definately going to look into that. I'm not sure of the components I would need though, it' looks really complicated and that you have to purchase a number of Megasquirt pieces to put together (sort of the Sauder furniture of auto mechanics.... )

That sounds like a great upgrade, I've only seen the HEI upgrades for Buick engines and mine is an AMC, does this mean I have to buy a Juicebox TEI upgrade instead and are there pro/cons on TEI -vs- HEI?

Wow, that sounds cool, but what do you mean replacing the headers?

How the heck do you do THAT?

You know, I thought of the same thing when I first started puzting with this jeep so I did a compression test and replaced the garbage oil pressure guage and everything seem to be within specs. This is a real beauty I got, an old man used it to rip tree trunks off his mountain property and it only has just under 13,000 original miles on it (but hard miles with the work it was doing)

 

Why not figure out what your gearing is first and then go from there. After all its free.

I'd also look into how well your current motor is running. I allways thought mine was a dog with the 258 and then I found out one of the cam lobes had been slowly grinding itself flat. After that I swapped in a stroked 4.0 and its all good!

Kevo

 

I just completed the HEI distributor upgrade on my 75 CJ5/258 and it made a huge difference in driveability. Cranks right up and silky smooth all the way up to redline. Plus, parts down the road are plentiful and inexpensive. Highly recommended.

You will see these available on ebay in the $150.00 to $200.00 range used with the 8mm wires and new they are about $325.00 w/o wires.

See link below for seller I picked mine up from :


http://cgi.ebay.com/ebaymotors/ws/e...d=1,1&item=7995315756&sspagename=STRK:MEWA:IT

 

Well, if it were mine, I'd keep the inline 6, but I'd replace the 232. The 232 Jeeps I've driven have been really wimpy. Only the cheapest buyers would skip the extra $50 for the 258 option.

In terms of HP per $ spent, the cheapest route is likely a used AMC 304 or a 360. Lots more issues to deal with though: motor mounts, radiator, plumbing, wiring, linkage, etc.

My preference would be to find a good used pre-1981 258 and build it. In addition to freshening up the internals, I'd go with a new cam, post 1980 AMC manifolds, TBI (throttle body fuel injection, either Howell or MegaSquirt), and HEI. I think you'd find that combination quite suitable. 258s are cheap on the used market - buy your replacement engine and drive your Jeep while you build the new engine.

All these Jeeps had a 3.73 axle ratio standard, with 4.27 optional. While the 4.27 ratio is desirable, I think you'll find the 3.73s fine for most purposes. One consideration is the transmission - the stock transmission behind the 232 or 258 will be the Borg-Warner T-14, and it may not last a long time behind a strong V8.

<edit> - oh - the 4.0L HO head is a great upgrade. You can use the post-1980 Jeep 258 intake manifold and an XJ exhaust with the 4.0L head. Either carburetion or TBI will work. If you can't afford the 4.0L head, stay with the stock 258 head and the later (post 1980) manifolds - don't use the stock cast iron manifolds from before 1981. And don't spend any money on an aftermarket 4-barrel manifold. The stock Jeep aluminum manifold is fine, and you can better spend your money elsewhere.

 

BTW if you want to upgrade your existing engine, the 258 is the same as the 232 except for the crank and rods. If you were to overhaul your existing engine, you could increase to 258 cid fairly easily.

 

Yea, I've been bummed out since I bought the Jeep (my first rebuild so I was and still am to a large extent green on this). In my research I've found 232's to be really tough to do anything to but the 258's you can do about anything you want. I've considered buying a rebuilt 258 for about $1,200 on the net. I would love to talk to someone who really tricked out there 232 and find out what they did and how they did it because if I buy a new engine it'll be my first engine swap (I'd probably take a class on it to be sure I go it right).

 

I doubt there's anyone out there who's spent a lot of time or effort on a post-71 232. You can increase the stroke of a 232 so easily by using a 258 crank, and used 258s are so cheap on the used market, that building a 232 seems kind of pointless.

If you have a garage where you can work, I'd suggest that you look around for a good used 258 to play with. What's your location? There may be somone in your area with one for sale. The post-80 258s are fine too, but the pre-81 engines have a heavier block and more counterweights on the crankshaft, which makes them slightly more desirable.

Check out Tom Monroe's book: http://www.amazon.com/exec/obidos/t...f=sr_1_8/104-1271324-5428720?v=glance&s=books
This is a good source for general knowledge on engine building. The best way to learn is to pick a project and try to do it - see if you can locate some friends that will help with advice and suggestions. Plus, someone here will be happy to comment on your ideas, plans and progress.

Building an engine is lots of fun.

hth Tim

 

Oh, and the removing/replacing of the engine is the easy part. Mostly that requires muscle... the "work" part of the project.