Replacement motor for the 258

Replacement motor for the 258

kev

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Take a look at this thread - http://www.jeep-cj.com/forums/f2/flushing-flooded-drive-train-406/

Lets say that you had a 1981 CJ5 with a 258 straight six. And the motor might need to be replaced, what you you do? Keep in mind that money is a factor. This is not the type of project that I can drop $1,000 on. Lets keep the price less then $400, maybe $500 at the very most.

What is the best replacement motor (new or used) for a 1981 CJ5 that currently has a 258?
 
replacement 258 engines are pretty easy to come by.




if it was me, i'd drop a few more $$ on it and throw a 360 in it...

edit: heres one in AZ....
AMC 258 I6 - $250 (Yuma)

Reply to: sale-1010681063@craigslist.org [?]
Date: 2009-01-27, 9:27PM MST


This engine was taken from an 82' AMC Eagle. This motor was running when removed. It is complete with head, valve cover, oil pan. This motor is a good candidate for 4.0L head conversion. I can e-mail pics if wanted. This is a heavy item. Buyer to arrange shipping / pickup. Open to other options.



another...http://easttexas.craigslist.org/pts/998256096.html


another one in TX...http://houston.craigslist.org/pts/1013019949.html
 
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replacement 258 engines are pretty easy to come by.

if it was me, i'd drop a few more $$ on it and throw a 360 in it...

You mean the 360s that used to come in the jeep trucks, like the J-10 and J-20?

I thought about getting a chevy v-6 with fuel injection from a junk yard. But then I would have to have an adapter plate.
 
For the least trouble and least amount of work, just pick up a 258. Luckily they are about the most plentiful and cheapest AMC engines around. Going the V8 rout will need motor mounts, exhaust adaption, cooling hoses and a few other parts.
 
You mean the 360s that used to come in the jeep trucks, like the J-10 and J-20?

I thought about getting a chevy v-6 with fuel injection from a junk yard. But then I would have to have an adapter plate.
CJ's came with 304's and the 360 block is the same, putting a 360 in a factory v8 Jeep is a breeze, putting one in a factory I6 requires a few parts.
 
You mean the 360s that used to come in the jeep trucks, like the J-10 and J-20?

I thought about getting a chevy v-6 with fuel injection from a junk yard. But then I would have to have an adapter plate.

you'd need a lot more than that. and with the budget you set, its not really possible.
 
Missed the part about the Chevy V6... Yep, wiring, exhaust, cooling, move trans mounts, floor board work, make or buy and weld motor mounts, fuel pump and a return line... More then that but that was off the top of my head...
 
Now this is what I call a good thread.


Missed the part about the Chevy V6... Yep, wiring, exhaust, cooling, move trans mounts, floor board work, make or buy and weld motor mounts, fuel pump and a return line... More then that but that was off the top of my head...

To be honest, I have not the time nor the money to do all of that.
 
I have a 73 258 motor that is stuck, not moving. Last used 15 yrs. ago. It looks good, the oil in the pan looks good. I have mystery oiled it, added penetrating oil to the cylinders and am going to keep trying to loosen it. Is this normal to unstick an engine? If i get it loose, what are the next steps in getting this motor going? I have almost no vehicle experience. !!!
 
I have a 73 258 motor that is stuck, not moving. Last used 15 yrs. ago. It looks good, the oil in the pan looks good. I have mystery oiled it, added penetrating oil to the cylinders and am going to keep trying to loosen it. Is this normal to unstick an engine? If i get it loose, what are the next steps in getting this motor going? I have almost no vehicle experience. !!!
Probably a dead motor. Most of the time when it sits long enough to stick you get rusted piston rings that wont ever seal again. Unfreeze the motor and rebuild it....................................Kev you will need to get a replacement 258 or a later 4.0
 
Probably a dead motor. Most of the time when it sits long enough to stick you get rusted piston rings that wont ever seal again. Unfreeze the motor and rebuild it....................................Kev you will need to get a replacement 258 or a later 4.0


gert,

Kev started this thread 02-01-09, he hasn't been around since 06-15-09, I don't think he's coming back :confused:


But yeah, gert's right, if it's been sitting for 15 years, even if you do get the motor unstuck you're definately going to have to completely tear that engine down and replace every gasket, every seal, every bearing, have the cylinder walls honed, everything. You may be better off searching craigslist and find a good used 258, it very may well be cheaper.
 
you know i completely agree with everybody above, but here's the thing if you could get it turning, it would be very interesting to see if you could get it running maybe throw some plugs in it, and rebuild the carb, just as a testament to how tough these old motors really are. i mean i wouldn't put a whole lot in it but it could be fun.
 
All info sounds correct. I think the idea of seeing if it will run is going to be interesting and fun. Heck, I am older than the jeep and i sort of work. So, I will try it and keep Jeepers informed !!!
 
All info sounds correct. I think the idea of seeing if it will run is going to be interesting and fun. Heck, I am older than the jeep and i sort of work. So, I will try it and keep Jeepers informed !!!
Dump some ATF down into the cylinders (through the sparkplug holes) and let it sit. You never know.
 
50/50 ATF and acetone. My favorite. If that don't work it ain't happening.:cool:
 
interesting revive of an old thread... why did you just start a new thread for that question as it is alot different than the subject of this one.....
 
I have heard of people also using kerosine to free up stuck engines. you might try that.
 
Ive tried the ATF in a 351, let it sit for a month, and nothing. It didn't want to turn anymore than it did the first day, but i have used PB blaster and after 2 hrs of sitting it didn't spin just right off, but it didn't take long before the whole thing was free like a new motor.
 

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