4.0 sohc swap

[73 camper special]

Good evening all. I have a question regarding an engine swap. I have a 2001 explorer with a 4.0 Soho. It developed serious oiling issues with the right cam. Needless to say the engine is now scrap. I am curious to know if anyone has ever swapped a 4.0 ohv in a vehicle to replace a 4.0 Soho? I'm not worried about a little power loss. I just need reliability. Thank you for any information!

 

[RonD]

The 4.0l OHV and SOHC used the same block so motor mounts and transmission will bolt up

You will need the 4.0l OHV computer and engine wiring harness

I assume Explorer has 5R55E automatic and thats going to be the problem
4.0l OHV came with 5R55E 1997 to 2000(last year for OHV), so you need engine computer from those years

1997-2000 5R55E were a little different than 2001 and up
The newer models had OSS(output shaft speed) sensor, which computer used for shifting and sent this "speed" signal out to speedo and cruise, you lose this "speed signal" with older computer
1997-2000 computer expects external speed signal from a VSS, to be coming in from GEM module, which 2001 Explorers GEM doesn't have
2001 Explorer should have 4WABS which did have a speed signal output already converted for use with older computer and speedometer
Worst case is you would add a Dakota Digital SGE-5E, to rear axle VSS wiring to get an adjustable speed signal for older computer and get speedometer back



4.0l SOHC was rated at 207HP
4.0l OHV was rated at 160HP
So that's about a 25% drop in power, 47HP

IMO, I would swap in a newer, 2005-2011, 4.0l SOHC, plug and play, and these have the newer designed timing chains and tensioners, so very reliable

 

[73 camper special]

RonD did the 4.0 Sohc have issues with the oil line above the cams plugging or the galleys plugging? This vehicle has 126,000 miles.

 

[RonD]

No, never read about that

The original tensioners would get failed springs, the springs hold the chains tight during start up before oil pressure takes over.
So chains would "bang" the guide on start up and eventually break it, and the "rattle" started at start up and mid-RPMs

New designed tensioners seemed to have solved that issue, but still recommend changing the 2 tensioners every 100k miles or so

 

[JohnnyO]

03+ 4.0 SOHC's have better timing chains. Lots of people put over 200k on them without issue. I'm approaching that myself. Also you're giving up 50 hp by switching to a 4.0 OHV. If you want a different engine you are far better off to find a wrecked Explorer with a 5.0 and swap that in.