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lnichola 06-21-2013 11:01 AM

Buying New Crate Engine – Which One for my ’85 CJ7?
 
Bought an ’85 CJ7 in 2011 and am finally getting around to replacing the engine. It is currently drivable, but I don’t trust it enough to take long trips and there are a few issues. It has an AMC 258 Straight 6 with 164k original miles. So, now that I’m ready to take the plunge, I don’t know if I should stick with getting the same engine or go with a fuel-injected engine.

Here are my concerns in making my decision:

1. My CJ has a 4 ˝” lift and I think a heavier engine (cast-iron block) will help prevent any unintentional rolling as opposed to an aluminum block. Thoughts?
2. It does not currently have any of the emissions stuff in the current motor (bought it off a guy in NJ where there was no annual emissions inspection at the time and I live in PA where we do have this requirement). Not sure if things like a vacuum canister come with new engines when you buy them or do I have to purchase all of that stuff separately?
3. New motor has to be 5-speed manual tranny compatible (not sure at this point if I have to replace the tranny, seems to work fine—just thought I’d mention).
4. Not concerned about speed (at all), but for being able to keep up with the flow of traffic, sometimes the current engine doesn’t have what I need. For example, for expressway driving I’m in 5th gear doing 55 mph (top speed) and have to go up a steep hill. About ˝ way up the hill I have to downshift into 4th gear because I’ve dropped to 45 mph and don’t have enough horses to get me the rest of the way up the hill staying at 55 mph. Beautiful puffs of blue smoke come out the exhaust any time I do this which is one of the “issues” I’m aware of. Whatever I get, I want it to be able to sustain 55 mph regardless of incline….I don’t think that’s too much to ask.
5. Personally, I’m not opposed to a carburetor vs. fuel-injection, but thought that if I went with fuel-injection it might get me a few more horses. Thoughts?
6. I have the tools and a cherry-picker and am considering swapping motors myself, but am no expert by any means. I know it will cost a lot more if I have someone else do the labor and am considering tackling this myself (with my husband’s help and he knows the same more or less as I do about this sort of thing). My former “Grease Monkey” experience includes:
a. Routine maintenance: Changing gaskets, oil & plugs, flush radiator
b. Adjusting timing belt
c. Checking compression in cylinders & checking for vacuum leaks
d. Dropping fuel tank to replace fuel sending unit
e. Many years ago, I pulled a Chevy 350 small block with a friend and replaced it after the pistons were bored out. I mention this because I’m thinking that this job would be similar in nature (disconnect stuff, unbolt the motor mounts, swap in the new engine, reconnect stuff)—or am I over-simplifying it?

Looking for opinions on this to help me make my decision. I am not concerned with trying to keep things stock, and am not inclined to “show” the Jeep either—just want to be able to depend on the vehicle with more comfort than what I have currently (with the original motor). Thanks!

John Strenk 06-21-2013 11:07 AM

Quote:

Originally Posted by lnichola (Post 15589896)
Bought an ’85 CJ7 in 2011 and am finally getting around to replacing the engine. It is currently drivable, but I don’t trust it enough to take long trips and there are a few issues. It has an AMC 258 Straight 6 with 164k original miles. So, now that I’m ready to take the plunge, I don’t know if I should stick with getting the same engine or go with a fuel-injected engine.

Here are my concerns in making my decision:

1. My CJ has a 4 ˝” lift and I think a heavier engine (cast-iron block) will help prevent any unintentional rolling as opposed to an aluminum block. Thoughts?

Rule of thumb. If it has to sit high, Make it light.
Besides, I don't think there is an aluminum block for the AMC 258

Quote:

2. It does not currently have any of the emissions stuff in the current motor (bought it off a guy in NJ where there was no annual emissions inspection at the time and I live in PA where we do have this requirement). Not sure if things like a vacuum canister come with new engines when you buy them or do I have to purchase all of that stuff separately?
Yep, but there are plenty of people always pulling stuff of that would be glad to get some change for it

Quote:


3. New motor has to be 5-speed manual tranny compatible (not sure at this point if I have to replace the tranny, seems to work fine—just thought I’d mention).
Not a problem, They all fit

Quote:

4. Not concerned about speed (at all), but for being able to keep up with the flow of traffic, sometimes the current engine doesn’t have what I need. For example, for expressway driving I’m in 5th gear doing 55 mph (top speed) and have to go up a steep hill. About ˝ way up the hill I have to downshift into 4th gear because I’ve dropped to 45 mph and don’t have enough horses to get me the rest of the way up the hill staying at 55 mph. Beautiful puffs of blue smoke come out the exhaust any time I do this which is one of the “issues” I’m aware of. Whatever I get, I want it to be able to sustain 55 mph regardless of incline….I don’t think that’s too much to ask.
You can cheat and change the gear ratio. My 1bb 258 Had no problem going 80 MPH Although I have a 4 speed with 3.50 gears. Not sure just how bad OD and 2.73 gears would be.


Quote:

5. Personally, I’m not opposed to a carburetor vs. fuel-injection, but thought that if I went with fuel-injection it might get me a few more horses. Thoughts?
Not enough to worry about but with FI everything else would be easier

But

Will the FI be allowable under PA emission laws. Does it have to be a complete FI system for that year or will you be planning to add the CA approved Mopar MPFI system. If it makes California happy I'm sure it will make PA happy.

Quote:

6. I have the tools and a cherry-picker and am considering swapping motors myself, but am no expert by any means. I know it will cost a lot more if I have someone else do the labor and am considering tackling this myself (with my husband’s help and he knows the same more or less as I do about this sort of thing). My former “Grease Monkey” experience includes:
a. Routine maintenance: Changing gaskets, oil & plugs, flush radiator
b. Adjusting timing belt
c. Checking compression in cylinders & checking for vacuum leaks
d. Dropping fuel tank to replace fuel sending unit
e. Many years ago, I pulled a Chevy 350 small block with a friend and replaced it after the pistons were bored out. I mention this because I’m thinking that this job would be similar in nature (disconnect stuff, unbolt the motor mounts, swap in the new engine, reconnect stuff)—or am I over-simplifying it?

Looking for opinions on this to help me make my decision. I am not concerned with trying to keep things stock, and am not inclined to “show” the Jeep either—just want to be able to depend on the vehicle with more comfort than what I have currently (with the original motor). Thanks!

Depending what way you go, with FI there could be a lot of new wiring and fuel line modification. How is your electrical knowledge?

95% will be bolt and play but it's that last 5% that will make you sell it as a rolling chassis.

wrongway92407 06-21-2013 09:25 PM

If you ase going to all the trouble to change the engine then pick up a used cherokee Grand would be better, rebuild the engine you will have all the emissions stuff for the engine and it will feel like it has twice the HP as the 258, put in the 4speed auto unless you are married to the T5 Its and easy swap if you don't want to fool with the wiring you can purchase a harness that is plug and play takes about an hour to install. Just because you don't have emission testing now its just a matter of time. I at one time wanted to install the GM OHV 4.2 but at the time they were hard to find and real pricey.

row684 06-23-2013 07:55 AM

Quote:

Originally Posted by wrongway92407
If you ase going to all the trouble to change the engine then pick up a used cherokee Grand would be better, rebuild the engine you will have all the emissions stuff for the engine and it will feel like it has twice the HP as the 258, put in the 4speed auto unless you are married to the T5 Its and easy swap if you don't want to fool with the wiring you can purchase a harness that is plug and play takes about an hour to install. Just because you don't have emission testing now its just a matter of time. I at one time wanted to install the GM OHV 4.2 but at the time they were hard to find and real pricey.

Or a used 5spd regular Cherokee with the AX15

NoNative 06-23-2013 08:27 AM

Quote:

Originally Posted by wrongway92407 (Post 15592229)
If you ase going to all the trouble to change the engine then pick up a used cherokee Grand would be better, rebuild the engine you will have all the emissions stuff for the engine and it will feel like it has twice the HP as the 258, put in the 4speed auto unless you are married to the T5 Its and easy swap if you don't want to fool with the wiring you can purchase a harness that is plug and play takes about an hour to install. Just because you don't have emission testing now its just a matter of time. I at one time wanted to install the GM OHV 4.2 but at the time they were hard to find and real pricey.

My 258 died about 3 months after I purchased it. Nice, huh? I elected to replace it with another 258 which I don't regret, but if I had to do it again, I'd follow these instructions and drop in a rebuilt 360 or 401 from a Waggoneer. :2thumbsup:


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