Time for a motor, Variances in the 2.5L

[TheDirtyJeep401]

Well, after running a compression test. Turns out the original 2.5 is worn out. Worse than I originally anticipated. I have a few 2.5s laying around but have few questions. 
 

I have an 92 2.5 sitting on an engine stand. From what I have found, all 2.5 blocks are the same. I know there is a slight variation in the heads over the years, but still work on a TBI motor. The big question I have is the cam. The TBI models from what I’ve seen have a slightly bigger cam than the MPFI models. So with that, does the MPFI cam work fine in a 86 TBI? Or does it need swapped over? Are there any other variations that would need swapped over other than the normal stuff (Intake,flywheel,sensors,etc..)?

[eaglescout526]

Flywheel you will need to swap. I don't know a lot about the HO year motors but I can’t imagine any issues with swapping a while HO motor to be with a Renix set up. 

[cruiser54]

Early 2.46s had a manual fuel pump on the block. That can be blocked off.

 

Your engine won't care which injection system you have or which cam you use. 

[TheDirtyJeep401]

On 11/6/2023 at 5:53 AM, cruiser54 said:

Early 2.46s had a manual fuel pump on the block. That can be blocked off.

 

Your engine won't care which injection system you have or which cam you use. 

 

 

On 11/5/2023 at 8:17 PM, eaglescout526 said:

Flywheel you will need to swap. I don't know a lot about the HO year motors but I can’t imagine any issues with swapping a while HO motor to be with a Renix set up. 

What about water pumps? It’s been a while since I put one in on the 86. I started tearing down the 92 and noticed that it has a reverse water pump. Did all of them have reverse rotation? Or is it something that they did on the 91+ motors? I can’t remember for the life of me on if the 86 was reverse or not. 

[eaglescout526]

84-86 had both V-belts and serps as an option. 87-01 was just serp so it really is more on the belt set up than anything else for the rotation of the pump. 

[GrandBoost98]

9 hours ago, eaglescout526 said:

87-01 was just serp

FWIW, I have an 89 with vbelts

[cruiser54]

Okay, so here's what we have.

 

Any 2.46 will work in a fuel injected application. 

 

You MIGHT have to install a fuel pump block off plate.

You need to be aware of which water pump your MJ uses based on the belt drive. v-belt or serpentine. 

[eaglescout526]

3 hours ago, GrandBoost98 said:

FWIW, I have an 89 with vbelts

WTF?! 

[acfortier]

3 hours ago, GrandBoost98 said:

FWIW, I have an 89 with vbelts

Are you referring to your Wrangler?

[eaglescout526]

I can see the 4.2L having V-belts in the YJ but not so much the 2.5L either.

[GrandBoost98]

Yes, I'm referring to my 89 YJ motor. eaglescout said 87-01 was serpentine, so I was assuming he was referring to any jeep 2.5L

[eaglescout526]

Most of the YJs I have seen have had the 4.2L and if I saw a 2.5L, it was a serp set up. So that’s interesting that Chrysler would’ve kept using the V-belts for the YJ when every XJ and MJ had serp for the 2.5L. 

[GrandBoost98]

I believe YJ 2.5Ls switched to serp in 90' or 91' when they also switched from TBI to MPFI.

 

[eaglescout526]

That’s a really weird anti saving money thing for Chrysler to do after they bought AMC.