Engine 1984 CJ7 Engine Swap

[bsetterlund]

I just bought a 1984 CJ7 2.5l 4 cyclinder jeep as a project. It has a new top end after the water pump died and blew the top end. It then was parked for 24 years and never used. I have not started it yet but was told this was the history with 166,000 miles on the rest of the motor. I am contemplating doing an engine swap and wanting to be judicious and not got crazy and want this to be as easy as possible. I also want to do this myself if I can for pride of ownership and would be the first time I have ever done anything like this. I am contemplating buying a 4.2l 6 cylinder crate motor. Does anyone have any recommendations about this choice and what I am going to have to replace other than a motor (obvious appropriate adapters) due to power increase (like transmission or transfer case, etc)?

 

[Belizean]

I just got finished doing pretty much all that about 10 months ago. Since you live in California I would first look into what the smog / state people will even let you change. Where I live I didn’t have to jump through hoops with a tail pipe test. I probably wouldn’t pass if I had to

 

[CJ]

As @Belizean said, the swap is pretty easy because the 258 i6 was a stock engine so all parts are readily available.
As stated the only concern is your CA smog, but If I remember correctly even though the VIN won't match the engine, as long as it has all the factory smog stuff you'll be ok.
Sine you don't list what transmission you have I'm assuming you have a 5 speed. They are pretty weak so a stronger trans. would be a good thought.

 

[hole]

I dont live there anymore but the best advice I can give you is to pay a visit to the nearest Smog Referee Station before you start buying parts. Ask alot of questions, take notes, there will be a test at the end.

 

[Belizean]

I would also say it depends on what you want to do with the Jeep. If you just want to tool around with it and are using for getting around town and staying off those high speed hi ways I would just fix the 4 cylinders and cruise around with that. I did that for 36 years. Even went on a couple 18 hours trips with it. Mine was starting to get a little worn out with 240K miles. I wanted to take some road trips and go into the mountains so I got a 6 cylinder and put fuel injection on it.

 

[bsetterlund]

I just got finished doing pretty much all that about 10 months ago. Since you live in California I would first look into what the smog / state people will even let you change. Where I live I didn’t have to jump through hoops with a tail pipe test. I probably wouldn’t pass if I had to

Very good point and thank you for bringing this up.

 

[bsetterlund]

As @Belizean said, the swap is pretty easy because the 258 i6 was a stock engine so all parts are readily available.
As stated the only concern is your CA smog, but If I remember correctly even though the VIN won't match the engine, as long as it has all the factory smog stuff you'll be ok.
Sine you don't list what transmission you have I'm assuming you have a 5 speed. They are pretty weak so a stronger trans. would be a good thought.

Thank you for this information. It was very helpful. I have a 4-speed and was looking at switching to a T5, however your statement of them being pretty weak is a concern and why spend money on a transmission that is still weak. What options do you think I might have switching to a stronger transmission that is daily stock and could possible just bolt right in to the stock 258 and the rest of the stock items?

 

[bsetterlund]

I dont live there anymore but the best advice I can give you is to pay a visit to the nearest Smog Referee Station before you start buying parts. Ask alot of questions, take notes, there will be a test at the end.

Great ideas! I will do this right away and before I start.

 

[CJ]

Thank you for this information. It was very helpful. I have a 4-speed and was looking at switching to a T5, however your statement of them being pretty weak is a concern and why spend money on a transmission that is still weak. What options do you think I might have switching to a stronger transmission that is daily stock and could possible just bolt right in to the stock 258 and the rest of the stock items?

As for trans missions the four speed could still be an issue... Take a look HERE (Link)-> Manual CJ Transmissions -< to find out what trans. you have.

Manual CJ Transmissions

T-90 Three Speed The Borg-Warner T90 was a strong three speed transmission that was used in CJs from 1945 to 1971. All the CJ2a's in 1945 and some in 1946 had a T90 with a column shift. The T90 had two knobs on the left side of the transmission. On T90's that had column shift this is...

jeep-cj.com

 

[Belizean]

I went from a T4 to T176. Both 4 speeds. Wish I would have just gone for a 5 speed. I probably spent less, instead of doing better. Next time.

 

[bsetterlund]

I would also say it depends on what you want to do with the Jeep. If you just want to tool around with it and are using for getting around town and staying off those high speed hi ways I would just fix the 4 cylinders and cruise around with that. I did that for 36 years. Even went on a couple 18 hours trips with it. Mine was starting to get a little worn out with 240K miles. I wanted to take some road trips and go into the mountains so I got a 6 cylinder and put fuel injection on it.

I do have some driving to the places that are the best to 4x4 at. I really want to do this right and once.

 

[bsetterlund]

I went from a T4 to T176. Both 4 speeds. Wish I would have just gone for a 5 speed. I probably spent less, instead of doing better. Next time.

Which 5 speed is there that fits well other then a T5, which is not really a preferred option?

 

[Belizean]

Probably AX15 would be an improvement worth doing.

 

[bsetterlund]

Probably AX15 would be an improvement worth doing.

Thank you very much. I am hot on the track and looking at that one now.

 

[Belizean]

Thank you very much. I am hot on the track and looking at that one now.

Lots of research

 

[CJ]

Manual CJ Transmissions

T-90 Three Speed The Borg-Warner T90 was a strong three speed transmission that was used in CJs from 1945 to 1971. All the CJ2a's in 1945 and some in 1946 had a T90 with a column shift. The T90 had two knobs on the left side of the transmission. On T90's that had column shift this is...

jeep-cj.com