4.0 engine rebuild

[90ranger90]

Hey everyone, I have a 1990 4.0 4x4 and the transmission just went out. My engine is leaking oil from various places also. I'm on the fence between selling or keeping. Im thinking of taking the engine out and rebuilding it myself (partly for fun).
So i have a few questions.

Is is worth it to get a rebuild kit somewhere, or is it a complete pain in the neck and i should avoid it at all costs

Any advice from those who have rebuilt them?

Thanks!

 

[AgInternational]

I as well was thinking of rebuilding my ranger's 4.0 due to it's problems. I've rebuilt one before but I had a long time to do it and had all the machine shop equipment and tools to do it in a shop. I won't have the same resources this time around. It's not too bad with a Chilton book, it gives all the steps and specs as well.

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[cp2295]

Easy motor to rebuild. Just be clean and organized. You’re going to want to tear it down and get specs before u purchase a kit, I’d say purchase all of it separately so you can get good quality products.

These motors are worth rebuilding imo.

Mark the cam synchronizer very good and precisely, it’s a real pita to get these things back in and reading correctly if you have to start from scratch.

Plan on doing pushrods and rockers. They will be worn out. Reuse the lifters, they are much better than any aftermarket and heads require removal to change (I learned this the hard way). Get the heads magnufluxed and checked for warpage these things are known for cracking heads.

Aside from that just do a normal rebuild. Take the block, crank, rods and pistons to a machinist and have them mic it out for you so you know what sizes to purchase.

If you’re wanting more power you can also put 95+ heads on it and get 10:1 compression vs 9:1.

Any other advice just ask, have fun!


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[90ranger90]

Thanks guys !

 

[AgInternational]

I've got a question. The engine in the truck still gets me around but has oil leaks and carbon buildup in the compression Chambers. Should I go pull a junkyard engine and rebuild it, or put my truck out of commission for a while so I can to that 4.0?

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[KBOI]

I've got a question. The engine in the truck still gets me around but has oil leaks and carbon buildup in the compression Chambers. Should I go pull a junkyard engine and rebuild it, or put my truck out of commission for a while so I can to that 4.0?

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With your engine, you know what you have. A junk yard engine could (potentially) take substantially more money to rebuild. Is your engine smoking, using oil, or knocking? If not, pull it and reseal it to stop the leaks, and pull the heads to clean the carbon. If it’s not using oil or making noises I would not spend the money to do machine work.

 

[Cmissle]

Don’t mean to hijack but do you know if a tranny(4x4) out of a 2000 4.0 will fit/work into a 1993 with 4.0/4x4?


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[holyford86]

With your engine, you know what you have. A junk yard engine could (potentially) take substantially more money to rebuild. Is your engine smoking, using oil, or knocking? If not, pull it and reseal it to stop the leaks, and pull the heads to clean the carbon. If it’s not using oil or making noises I would not spend the money to do machine work.

This is where I'm at, if it runs fine, just re-gasket and clean parts, it's best to not poke the bear in this respect. My engine swap donor was a grease ball when I got it, I replaced all gaskets and it has given me 100k trouble free miles and still has 50psi oil pressure when hot.

Don’t mean to hijack but do you know if a tranny(4x4) out of a 2000 4.0 will fit/work into a 1993 with 4.0/4x4?

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If it's a manual trans it will be almost a direct swap, a 93 will have a neutral sensing switch in the top cover that a 2000 does not have, if you're picky like me you'll swap the top cover and replace the shifter bushings and seal, if not, you may get a code for the missing sensor. You will need the shifter for the 2000 in this case though, they mount differently to the shifter stub and the stubs are different so they will not interchange. If it's an automatic you will need to swap the entire engine management system with it as the transmission in a 2000 is fully electronically controlled.

 

[Cmissle]

Ok, and it is a 5spd. Do you happen to know what I would have to do with the speedometer cable? The 1993 is cable driven and the 2000 is not


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[holyford86]

Ok, and it is a 5spd. Do you happen to know what I would have to do with the speedometer cable? The 1993 is cable driven and the 2000 is not


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If it's a 4x4 you will just need to swap the transfer case from your 94 onto it, if it is a 4x2 you will need to swap the tailshaft housing and transfer over the speedometer drive gear. I am not sure if the 2000 tailshaft will be machined to accept the gear though as pretty much all of my experience is with 4x4s

 

[Cmissle]

Gotcha, well they are both 4x4. So it looks like I need to get a 1993 t-case to get my speedometer cable to work. But if I didn’t care about the speedo cable, everything else should still work, correct?


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[AgInternational]

With your engine, you know what you have. A junk yard engine could (potentially) take substantially more money to rebuild. Is your engine smoking, using oil, or knocking? If not, pull it and reseal it to stop the leaks, and pull the heads to clean the carbon. If it’s not using oil or making noises I would not spend the money to do machine work.

I use higher octane fuel so it won't predetonate really bad when under some load. I add a quart of oil every 3-400 miles, it shows drip stains where I park, but I'm not sure if that is where all the oil is going. It started knocking worse after I did the lower intake gasket the first time. I assume it didn't have a good oil seal so I did it again, still didn't work.

Would it be easier to pull the engine and do the top end, or do it in vehicle?

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[holyford86]

if you're using the one piece fiber "tray" type gasket for the lower, they don't seal for crap, Best to use the updated two piece rubber and steel type gasket and a liberal amount of gray RTV on the front and rear of lifter valley. It is definitely doable in truck, they are very easy to tear down and reassemble in there, everything is relatively easy to access.

 

[KBOI]

I use higher octane fuel so it won't predetonate really bad when under some load. I add a quart of oil every 3-400 miles, it shows drip stains where I park, but I'm not sure if that is where all the oil is going. It started knocking worse after I did the lower intake gasket the first time. I assume it didn't have a good oil seal so I did it again, still didn't work.

Would it be easier to pull the engine and do the top end, or do it in vehicle?

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That sounds a little rough. If you’re adding that much oil, the puddles it leaves would be substantial. I think I’d do a compression check and see what the results are, maybe platigauge a main and rod bearing to check the wear. Once you know these numbers you can gauge the wear on your engine.

 

[90ranger90]

When i pull my engine i want to get an upgraded cam, do you know of any that are California legal? I want it to still pass smog