i've just found out that the 4.6l engine in my 97 f150 is leaking antifreeze from the block due to rust and corrosion.Actually it is more of an ooze than a leak.Although i plan to drive it as is for now i know i need to decide what action to take soon.I recently purchased a 97 f150 2wd 5.4l parts truck.(i wanted the flareside bed on it).Is it possible to swap the 4.6 in my 4wd with the 5.4 2wd parts truck.They are both 97's.The spare motor i have has 110,000 miles on it though.If possible is it even worth it?Should i have it rebuilt or purchase a new or other already rebuilt 4.6 motor.Most people i talk to have told me to sell my truck before it gets worse but i've finally got my truck looking the way i want and have a bit invested as well so i want to keep it.Any suggestions and what i might be looking at moneywise would be greatly appreciated!!TY1

 

ive never heard of a block rusting thru like that. your freee plugs could be leaking. thats not that hard of a fix. id get some other opinions before making a big decision.

 

Yes. Been there done that, bought the T-shirt.

See below:
Notes for 4.6 to 5.4 swap

Exhaust: The collectors on the exhaust manifolds are set at different angles and locations. The 4.6 exhaust will not bolt up to 5.4 manifold.

Ignition: All 5.4 engines use Cop ignition. 97-99 4.6 engines use coil packs. It is easier to wire your 5.4 using the harness from the 4.6 and the 4.6 ignition coil packs. If you use the 4.6 Coil pack ignition you will have to fab a bracket for the driver side coil pack.

Engine harness: The IAC harness must be relocated to the rear of the throttle body elbow. The oil sender wire on the 4.6 is too short so it must be extended. All 97-00 4.6 engines use some sort of intake manifold runner control valve. Remove it from the 4.6 and plug it into the 4.6 harness and bolt it to the engine some where out of the way. Note you can get a tune to remove its function and eliminate it all together. All 97-98 4.6 engines use an engine coolant temp sensor. Some use 2. None of the 99+ 5.4s use any. You will have to tap the intake manifold crossover pipe to fit the sensor. Some 4.6 engines (97-8) have two sensors.

Transmissions: the 4.6 and 5.4 have the same bellhousing bolt pattern. That means that all the transmissions will bolt up. All the 5.4 engines have 8 bolt crankshafts. Some 4.6 engines (ROMEO ENGINE) have 6 bolt cranks. You will need the flex plate from the 5.4.
Manual transmissions: If you don’t have an 8 bolt flywheel a flywheel from a 1997-8 4.6 Windsor engine will work. As it has 8 bolts it will bolt right up to the 5.4 crank. Remove the flex plate spacer and install a pilot bearing from a 4.6.

Tuning: It is best to have a custom tune done to accommodate the extra displacement of the 5.4.
You should be able to use the 4.6 MAF as any competent tuner can adjust for it. It is always best to discuss this with your tuner.

Misc: Both engines use the same engine mounts and their location on the block are also the same so your old ones will fit. Unbolt and place aside the AC and PS. You need to remove the intake manifold for the engine to come out. Yes there are 3 bolts on the starter.

Knock Sensor:
The 97-98 99 4.6 uses a 2 wire knock sensor. The 97-98 5.4 has 3 wires of which one is a ground. Both have a Yellow /red wire to pin 57 on PCM.

1997-98-99-2000-01 Yellow/red to 57 on PCM 4.6 Same for 5.4.
97-98 Pin 91 feeds power for 4.6 and other components. Same for 5.4
1999- 2000-01 Pin 32 for power. Same fore 5.4
2002+ Cannot confirm.


JMC

 

Thank you for taking the time to post all the helpful info.Now that I know the two motors are interchangeable my decision is a little easier.What is your oppinion on having the 5.4 rebuilt before installing it in my truck?I'm thinking maybe pull the 5.4 now and bring it somewhere to be rebuilt(even if it takes a month or two)drive my truck as is for now and when ready slap in the 5.4.Do you have an idea on the roundabout cost of a rebuild?Does rebuilding it make sense moneywise or should i look for a motor already rebuilt.I'm not so sure putting a motor with 110,000m in without rebuilding is a good idea.TY again for all your help!!

 

The cost of rebuilding the engine would be the same as if you went out and purchased a remanufactured engine. Would I put in a 100+ engine? Maybe. I would wand to, at the very least, see the compression test numbers. Pulling engines for me is no big deal so I would pop that sucker in and drive it. If it blows, oh well..... But that is just me. When I am done writing this I have to go outside and pull my manual tranny to see why it is stuck in 1st gear. All in days work.


JMC