What items to replace while swapping lower mileage 4.0?

[jfisher]

Truck is a 1994 Ranger with the 4.0. A valve is sticking on the driver side head and the truck is missing. It can be tought to start at first, but once it gets going, it's fine. I decided to replace the entire engine(163k) instead of fixing the head because the oil filter is almost rusted through on the truck currently, so I can tell this engine has not been taken care of.

This past weekend, I picked up a supposedly 66k mile 4.0 OHV. Not sure what it came out of, as I bought it off a guy who bought it from a junkyard. It supposedly came out of another 94' Ranger, but I don't really pay attention to hearsay. The engine was a little grungy and looked like there may be a possible leak at the back of the intake manifold. I degreased the engine and it cleaned up well and I'm now looking to do some maintenance on the engine before I drop it in.

What all do you recomend I replace? I'm definitely going to do valve cover, exhaust, and oil pan gaskets, as well as the rear main. I'm not sure if the lower intake manifold uses a gasket or not, as I only see black silicon now. Either way, I'll pull that off and re-seal/replace the gasket.

Anything else I should replace while I have the engine out and on a stand??

 

[Big Jim M]

Grungy engine?

Truck is a 1994 Ranger with the 4.0. A valve is sticking on the driver side head and the truck is missing. It can be tought to start at first, but once it gets going, it's fine. I decided to replace the entire engine(163k) instead of fixing the head because the oil filter is almost rusted through on the truck currently, so I can tell this engine has not been taken care of.

This past weekend, I picked up a supposedly 66k mile 4.0 OHV. Not sure what it came out of, as I bought it off a guy who bought it from a junkyard. It supposedly came out of another 94' Ranger, but I don't really pay attention to hearsay. The engine was a little grungy and looked like there may be a possible leak at the back of the intake manifold. I degreased the engine and it cleaned up well and I'm now looking to do some maintenance on the engine before I drop it in.

What all do you recomend I replace? I'm definitely going to do valve cover, exhaust, and oil pan gaskets, as well as the rear main. I'm not sure if the lower intake manifold uses a gasket or not, as I only see black silicon now. Either way, I'll pull that off and re-seal/replace the gasket.

Anything else I should replace while I have the engine out and on a stand??

A 66K engine shouldn't be grungy!! I betcha the engine you have in that ride is a better engine with fewer miles on it.
I'd do a compression check on your engine and replace the valves that are burnt and go about my business..
Big Jim

 

[fireguy12117]

take a look at the technical library under the 4.0 sections. there are many tips in there that might help you decide what you want to go after. there are lots of threads in here too about people doing exactly what you are doing and many ideas on what to look at get mentioned.

as mentioned, a compression test, the push rods tend to wear so id look at those close. the lower intake does have a gasket. many on here say felpro gaskets suck, get the ford OEM for this application, however i never got a clear sense if that was because of difficulty in installation or actual quality of gaskets. i have a rebuilt with felpro but not enough miles to be confident it saying felpro was ok. new ford gaskets are a bit pricey, but probably worth is since another weak spot on the 4.0 is vacuum leaks on the lower gasket.

 

[jfisher]

A 66K engine shouldn't be grungy!! I betcha the engine you have in that ride is a better engine with fewer miles on it.
I'd do a compression check on your engine and replace the valves that are burnt and go about my business..
Big Jim

That's what I'm thinking, but this engine is WAY cleaner that what is currently in the truck. I've done a compression check on mine, and the compression is definitely down in one of the cylinders(not sure how the numbering works on these 4.0's).

After the labor costs and cost of having the head redone, I'd be coming out ahead with using the "new" engine. But then again, I'm taking a risk not knowing the history of the new engine. Maybe I'll just swap heads???

 

[jfisher]

This has me thinking....

I'm going to try the "simple" fixes tonight and post up my results. I'd love to be able to not pay the $500 labor to have the new motor put in. I'm going to do another compression test tonight to find out exactly which cylinder it was(5 I think after seeing the tech diagrams).

If I accelerate hard, the truck will have no power and fall on it's face. If I accelerate just hard enough to the point right before it falls on it's face, I will get a CEL temporarily then shuts off after I drive it normally.

 

[Beef52751]

If I accelerate hard, the truck will have no power and fall on it's face. If I accelerate just hard enough to the point right before it falls on it's face, I will get a CEL temporarily then shuts off after I drive it normally.

That doesnt sound like a stuck valve to me

 

[Ranger44]

Anyway one of the cylinders doesn't have compression. Just swap the engines out.

I'd consider almost any Ranger engine as disposable. There is plenty of them around and many in salvage yards. An engine is more easily swapped in than rebuilt.

As for what to replace......simple tune up items would be a start.

Plugs, wires, thermostat, maybe the waterpump. Give it fresh coolant and oil. Ready to roll.

 

[dangerranger911]

Anyway one of the cylinders doesn't have compression. Just swap the engines out.

I'd consider almost any Ranger engine as disposable. There is plenty of them around and many in salvage yards. An engine is more easily swapped in than rebuilt.

As for what to replace......simple tune up items would be a start.

Plugs, wires, thermostat, maybe the waterpump. Give it fresh coolant and oil. Ready to roll.

i agree but if the lower intakes has silicone protruding from lower intake i would go ahead do it also valve cover gaskets upper, lower intake oil pan, and rear main it will help keep your engine alive for little longer and to ensure no leaks and headaches. but that's my opinion

 

[jfisher]

That doesnt sound like a stuck valve to me

Why do you say that?

It makes sense to me perfectly. When I floor the truck, the valve sticks open and all of the incoming air goes right back out the exhaust. So the engine revs like normal, but just doesn't go anywhere.

 

[jfisher]

I changed all the plugs today to autolite platinums. I gapped them all at .054. I changed the wires to bosch wires and changed the oil. No difference in how the truck runs at all, except now the battery dash light is on? I had the battery and the alternator checked and both are fine?

The number five plug was covered in oil. That could also be because of the valve cover leak right above that plug as well though.

 

[Big Jim M]

Why do you say that?

It makes sense to me perfectly. When I floor the truck, the valve sticks open and all of the incoming air goes right back out the exhaust. So the engine revs like normal, but just doesn't go anywhere.

The only "stuck valves" I ever saw had been hit by the piston and wouldn't EVER close.. They had a permanent miss leading to total engine failure.
Just the term "stuck valve" doesn't make sense..
Please explain how a valve can intermittently get stuck!
Big JIm

 

[fireguy12117]

I'd also want to capture what the code was on the CEL light. i'd duplicate what causes it to come on and then scan and see what number it is. could be a clue as to why it wont rev up smoothly.

no garuntee, but almost sounds like maybe a throttle position sensor not reading right in a certain spot. you have the pedal to the floor so the choke plate is wide open, but the PCM thinks you're at some other point in throttle...

 

[Ranger#1]

I'd consider almost any Ranger engine as disposable. There is plenty of them around and many in salvage yards. An engine is more easily swapped in than rebuilt.

i second thiss movement there are wayyyy tomanny lo milage 4.0 out there shit they came in like evrething

 

[jfisher]

I'd also want to capture what the code was on the CEL light. i'd duplicate what causes it to come on and then scan and see what number it is. could be a clue as to why it wont rev up smoothly.

no garuntee, but almost sounds like maybe a throttle position sensor not reading right in a certain spot. you have the pedal to the floor so the choke plate is wide open, but the PCM thinks you're at some other point in throttle...

It revs up smoothly, it's just that when I'm driving it and I floor it, it just doesn't go anywhere. It revs up, but just isn't making any power and bogs. If I get on the throttle harder than normal but do it smoothly without flooring, the truck will pull pretty hard. This is when the CEL comes on, but it goes off within seconds as soon as I return to normal throttle driving.

 

[fireguy12117]

the code should still be in the memory to be scanned. i forgot what the two 'memory' types are, but if the CEL came on recently and went away it should still be scannable.

and uh...i'm racking my brain but can't come up with anything good for that description...

is the current engine thats in the truck now, the original engine with the truck?