what year 4.0l long blocks will work in my 91 ranger?

[rickcdewitt]

well my donor 4.0l had the upper intake loosened at one point so that water was able to get into the intake and past the valves in a few cylinders and sit for a year or so.it was already bored .030 so its a parts motor now.
anyway i heard that you coulden't run a fast burn long block in an early(91-94)4.0l truck.ford supposedly says you will melt it down if you do.what from?detonation?if i could get a low mileage 95-2000 long block in my truck it would be easier to find in junkyards.i know the exhaust manifold is different on the new head but can i keep the first gen intake or is it relatively easy to swap to a late model intake(yes i need to change all the sensors too.)?

 

[rickcdewitt]

i know the open chamber 91-94 long block is bolt in.anyone have experience with a fast burn long block in their 90-94?

 

[woodyedmiston]

Sort of . . .

I put a 92-93, not sure which now, explorer motor in my 99 ranger - I changed nothing about the electronics - just bolted in the motor with the intake and injectors from the 99 - runs fine. Look closely at the mounting holes on the side of the block - some are different, don't remember which - I had to make a motor mount for the left side of my swap.

That "burn it down" comment in the 4.0 rebuild section of Tech is really conjecture as I read it - not really personal experience. If you look at the pistons there is little difference.

 

[rickcdewitt]

yeah the pistons are similar but the heads are much different.i'm wondering if the early motors ran more advance than the fast burn heads like,or something to do with mixture?

 

[woodyedmiston]

Rick:

This is where I think the idea comes from - it is in the Tech Library, Engines, 4.0 rebuild - scroll down till you see pistons:

"Ford introduced another new head in ’98. The exhaust ports on the 98TM-AD were much narrower than they were on the earlier castings; they measured 1.40˝ across the port compared to 1.70˝ on the 95TM/97TM castings. According to the engineers I have talked to, the smaller ports increased the velocity of the exhaust gasses so they carried more heat down to the catalytic converter. This helped the converter “light off" sooner, so it did a better job of reducing emissions during the critical start-up and driveaway phase of the EPA emissions test. With that in mind, it’s probably not a good idea to swap these heads back and forth with any of the earlier castings."

Now -- you will notice they are talking about head design and port size and cats. If you are using the older head on the later short block you are going to have is LOWER compression ratio because the dish in the piston is larger. The later head has a smaller combustion chamber compensating for it.

If you are talking about placing the entire late model long block into a later truck - you probably are not going to have a problem. Someone who has more experience with reprogramming the computer could tell you if there is a way to optimize your truck.

The pipe flanges for my 99 ranger fit up to the exhaust headers on the older motor - I didn't see the difference until the motor was in the car. But, the bolt spacing on the flanges is different. Rather than swap them I just slotted the flanges on the y-pipe. You might be able to do the same thing if that is a problem.

 

[rickcdewitt]

you are probably right about just programming the cpu to work with the late model block,although in that same article they talk about the motor melting down in just a few thousand miles.sounds like a serious issue somewhere in the tuning.i've read the whole tech article and wondered if anyone had done the swap to late model so i posted this up.

 

[shadetreeranger]

i put a 99 4.0 in my 91 i have about 13,000 miles on it now.
swapped out the intake, the crank sensor,exhaust manifolds to eliminate the egr, left everything else alone. 99 has a cam sensor in the back where a distributor might go just left it in no need to hook it up. did not reprogram ecu.

 

[shadetreeranger]

i put a 99 4.0 in my 91 i have about 13,000 miles on it now.
swapped out the intake, the crank sensor,exhaust manifolds to eliminate the egr, left everything else alone. 99 has a cam sensor in the back where a distributor might go just left it in no need to hook it up. did not reprogram ecu. i believe any 4.0 will work.

 

[woodyedmiston]

Other differences

If you look in the tech section for 4.0 rebuild there are some pictures of the differences in the number of holes in the side of the block. My back dated 93 engine did not have enough holes for the 99 engine mounts. I managed to fab something easily enough - but there is a difference in the blocks as they get newer.