downsize 4.0

[skines]

Hy,
I'm new here, and actually not even an owner of a Ranger. I can get a good deal on 91 4.0 Automatic, with a wrecked engine. It has been driven without oil, what usually never ends well.
I possible have an rebuild 89' crate engine at hand, also for a very good price, but it's the 2.9l... My understanding is it would not be complicated to switch the engine, except I had to switch the wiring harness and computer too. Is that correct?
Besides that, would you even consider doing that?
I don't have any experience with the different makes and Years of the Rangers and engines, so every input is appreciated.
Thanks

 

[bmerr98]

I guess it would depend on your plans for the truck, how mechanically inclined you are, how your work area is set up, etc. Might be a cheap little get around rig or a big pain in the anus that you'll be trying to get rid of for pennies on the dollar.

Details man! We need details!

 

[skines]

Alright details...
Well, I changed recently the head gasket on my subaru, had to pull the engine for that too. Worked for years a s a Motorcycle mechanic and later as a mechanic in nuke plant. I have more or less the tools I need, and a space to work on it with a roof over my head too.
I guess my question is, how much more effort in comparison to just replace it with another 4.0, it's going to be.
I get the truck for $150 and the rebuild crate engine for about $300. In you're experience what expenses will it be if you want to get a 4.0 from another vehicle?

 

[RonD]

Yes, you need to get the computer and wiring from the 2.9l to put into the 4.0l.

Automatic trans and manual trans models use different computers.

Should be well within your abilities, most of it is just "lefty loosy, righty tighty" wrench work , so boring

The 2.9l had an oiling issue in the valve train but if it's been rebuild that shouldn't be an issue until the miles get higher.

4.0l would be a better swap, no rewiring or computer needed, and more power than 2.9l, but 4.0l's are harder to come by at a good price.

Maybe you could find a 4.0l short or long block for a good deal, you have all the external bolt on parts from the original engine.

 

[skines]

So, I got the Ranger today, it's an 91' XLT 4.0l Automatic AWD.
The previous Owner couldn't tell me exactly what happened but some problem with the oil flow, anyway the engine stalled. I tried to turn the crankshaft with a breaker bar, after removing the front belt, nothing... I drained the oil and couldn't see any metal shaving or sings of seizing in it.
So now my question, what do I have to do best to make the final decision on the engine? Take the oil pan off, or the valve covers? Could it be worth it to rebuild the engine at all, or you just would swap it out?
Thanks for help...

 

[RonD]

If you can not turn the crankshaft at all then main bearing(s) are seized, if that happened then all the other bearings and oil lubricated parts are in question.

So yes total tear down, inspection and rebuild.

Cost and time are what you need to consider, either way the engine needs to come out.
Once it is out and heads are off you can make a more inform decision about it's rebuild condition/cost.

Weigh that against cost of a used engine and it's unknown history, and the cost of a rebuilt engine with a known history.
I.e. how many miles on the truck now, will the rest of the vehicle last long enough for a new(rebuilt) engine to be worthwhile?