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Cooter's Explorer 5.0/4R70W Swap

Cooter_76

Sr. Member
Joined
May 18, 2004
Messages
863
To make a long story short, I’m tired of chasing overheating issues with my current engine, and I’d really like to have an overdrive. A few months ago I bit the bullet and bought a used Explorer for the popular 5.0/4R70W swap.
There’s a lot of info on this site about these drivetrain swaps, but it can be difficult to nail-down every little detail with so many different options out there. I thought I’d start my own thread to keep my thoughts in order and hopefully get some tips/advice from those who have successfully finished one of these projects.

The Donor

41682356850_f914ea9a81_z.jpg

I picked-up a running AWD ‘96 Explorer with 163K miles off Craigslist for $600. It had a lot of little body issues and something heinous going on in the front end, but the engine ran well and the transmission seemed to shift fine. I hauled it to a friend’s shop so we could pull the drivetrain, wiring harness, etc. Got $200 for the shell at the recycling center. So far I’m in for $400. ;D
I’m on EFI Guy’s list for computer and wiring harness work, and will plan to get things in order to swap everything over this fall/winter.
 
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Cooter_76

Cooter_76

Sr. Member
Joined
May 18, 2004
Messages
863
The Engine

The Explorer had a check-engine light on when I purchased it. I pulled a P0402 code, which is EGR-related, so that may need to be cleaned or replaced.
I sent an oil sample off to Blackstone Labs for piece of mind. The report came back clean, with a little commentary about Broncos vs Explorers:

42585896755_f55534bb22_z.jpg


Question time:
- Since this engine has non-P heads, I should be able to use the existing long-tube headers I have on my 302, correct?

- I plan to re-seal the valve covers, oil pan and a few other areas to take care of some oil leaks. Also planning to replace the timing chain, water pump, thermostat and possibly starter since it looks to be original. The alternator was charging and the PS pump looks to be in good shape. Is there anything else on the engine that I should replace while it’s out of the Bronco, like maybe the oil pump?
 
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Cooter_76

Cooter_76

Sr. Member
Joined
May 18, 2004
Messages
863
Transmission

The transmission has a slight leak at the output shaft, so at a minimum it needs a new seal. I’m thinking about trying my hand at rebuilding the transmission myself, following the videos from transmissionbench.com. I’ve watched all the disassembly videos and it doesn’t look too daunting (so far.)
There’s been some mention of the ‘97.5+ 4R70W’s being stronger. Something about a diode. Is this significant enough to consider upgrading some of the internals to the later version? I’ll likely change from the current 32” tires & 3.50 gears to 33’s and 4.56’s after this swap is complete (and my pocket book has had a chance to recover.)
 

904Bronco

Contributor
Bronco Guru
Joined
Sep 28, 2004
Messages
5,749
Loc.
San Martin, CA
Thats a lot of questions... ;D

I am on my 3rd Explorer conversion, this one has a NV3550 in it and will stay.

Motor. Nice to get a report on the oil.... Yes > R/R timing chain, water pump, gaskets, thermostat, and oil pump. I would say spark plugs and wires, depending on condition when removed and inspected...
PCV filter replace below the rubber grommet and valve... Inspect.
I don't have a problem running original Ford parts if they are still functioning (starter). A higher quality than replacements from local auto parts stores.

The later 4R70W have stronger internals than the early ones. They can be upgraded... I have always left tranny work to local shops, more than I wanted to bite off.

If the GT 40 heads, (3 slashes on the heads casting) then standard headers should bolt up without sparkplug interference.
 

SavageBurro

Sr. Member
Joined
Aug 12, 2013
Messages
588
speaking specifically to the quality ford parts. I installed an explorer 5.0 w 68k miles (if I remember correctly). I bought a replacement new timing set from ford. when I compared the new set to the used set it the engine... the used one had less slop and appeared to be of better quality... so I kept the used and returned the new.

I agree w 904Bronco.

I also got rid of oil cooler to gain frame clearance... did an adapter to use standard 302 filter (short one).

if u want more hood clearance.... w.h. sells a p.s. bracket adapter to use Saginaw pump... vs modifying to use explorer pump. (lots of people use explorer pump though). not sure if ac Will fit. others can speak to that. if it doesn't then diff serp belt needed. might need smaller pulley on lower pulley closest to crossmember. lots of little misc stuff.
 

SavageBurro

Sr. Member
Joined
Aug 12, 2013
Messages
588
With the oil test, do they explain what are appropriate thresholds for levels of what is bad, good, acceptable etc.? Just curious. Someone could send me a sample that reports 4 parts Vibranium and I wouldn't know if that's good or bad.
 

mtp71174

Full Member
Joined
May 8, 2007
Messages
204
Change the oil pump drive shaft to an arp (like in the bolts) shaft the tend to twist off change it, it is good insurance.
 
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Cooter_76

Cooter_76

Sr. Member
Joined
May 18, 2004
Messages
863
With the oil test, do they explain what are appropriate thresholds for levels of what is bad, good, acceptable etc.? Just curious. Someone could send me a sample that reports 4 parts Vibranium and I wouldn't know if that's good or bad.

I would think that if your oil had ANY Vibranium, that would be pretty valuable. :D

The column on the right shows "Universal Averages" which is what they would expect to see. I don't know if that's based on similar engines with similar mileage? The comments section of the report is where they boil it down for you. My F150 showed slightly elevated silicon levels. In that case they recommended changing the air filter and cleaning the intake tube.
 

SavageBurro

Sr. Member
Joined
Aug 12, 2013
Messages
588
I would think that if your oil had ANY Vibranium, that would be pretty valuable. :D

The column on the right shows "Universal Averages" which is what they would expect to see. I don't know if that's based on similar engines with similar mileage? The comments section of the report is where they boil it down for you. My F150 showed slightly elevated silicon levels. In that case they recommended changing the air filter and cleaning the intake tube.

Yeah, I saw the averages column. And sorry to get this somewhat off topic....and this is simply for the sake of curiosity. I just didn't know if they tell you that being below or above certain levels is better or worse etc. (I saw the narrative as well). For example in drinking water tests, they state that above 10 parts arsenic is bad, below is ok (or something along those lines). Couldn't help myself with the quip on vibranium :)
 
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Cooter_76

Cooter_76

Sr. Member
Joined
May 18, 2004
Messages
863
It's been a busy summer, but I've finally found some Bronco time lately. I have the wiring harness un-taped and ready to send to EFI Guy. Also started pulling things apart on the engine. Nothing's ever simple.
First I broke the head off one bolt that holds the water pump/timing cover on.

43857641575_f7c9a207fa_z.jpg


Apparently it's common to have a few bolts that corrode and get stuck to the timing cover. It took a while to persuade the timing cover off. Fortunately the bolt was easy to unscrew from the block once the cover was out of the way.

Then I decided to pull the lower intake so it could be cleaned to match the other aluminum parts. In the process I managed to break the front passenger side bolt off in the head.

44048212564_9a19ebcfec_z.jpg


I tried heat & PB Blaster, then I attempted to weld a nut on the end, and lastly I tried an extractor.

30896032588_a3cac5fea9_z.jpg



Perfect:
29829733207_8f64f597e6_z.jpg


Two days and $100 later, I picked up the head from a local machine shop who pulled the bolt and the extractor for me. Time for new head bolts and gaskets. This is deeper into the engine than I'd planned to go, and friends are telling me I should go ahead and replace the cam at this point.

Is it foolish to get this far in and not replace the cam?
 

74fiberglass

Sr. Member
Joined
Nov 27, 2005
Messages
900
I also broke a bolt off in the head . Had friend at machine shop get it out. Motor is still sitting on a stand . Someday i will get to it ..
 

Teal68

Contributor
Bronco Guru
Joined
Mar 28, 2013
Messages
2,566
Loc.
Inlet Beach
This is deeper into the engine than I'd planned to go, and friends are telling me I should go ahead and replace the cam at this point.

Is it foolish to get this far in and not replace the cam?

About to drop a Mountaineer motor in too so I'm curious what comments you get about the cam.

Keep us posted on your progress.
 

jbawall

Contributor
Full Member
Joined
Jul 14, 2004
Messages
314
Loc.
Edgewood, Washington
It's been a busy summer, but I've finally found some Bronco time lately. I have the wiring harness un-taped and ready to send to EFI Guy. Also started pulling things apart on the engine. Nothing's ever simple.
First I broke the head off one bolt that holds the water pump/timing cover on.

43857641575_f7c9a207fa_z.jpg


Apparently it's common to have a few bolts that corrode and get stuck to the timing cover. It took a while to persuade the timing cover off. Fortunately the bolt was easy to unscrew from the block once the cover was out of the way.

Then I decided to pull the lower intake so it could be cleaned to match the other aluminum parts. In the process I managed to break the front passenger side bolt off in the head.

44048212564_9a19ebcfec_z.jpg


I tried heat & PB Blaster, then I attempted to weld a nut on the end, and lastly I tried an extractor.

30896032588_a3cac5fea9_z.jpg



Perfect:
29829733207_8f64f597e6_z.jpg


Two days and $100 later, I picked up the head from a local machine shop who pulled the bolt and the extractor for me. Time for new head bolts and gaskets. This is deeper into the engine than I'd planned to go, and friends are telling me I should go ahead and replace the cam at this point.

Is it foolish to get this far in and not replace the cam?


The same bolt broke for me, machine shop visit took care of it too.
 

sykanr0ng

Bronco Guru
Joined
Aug 11, 2014
Messages
5,363
This is deeper into the engine than I'd planned to go, and friends are telling me I should go ahead and replace the cam at this point.

Is it foolish to get this far in and not replace the cam?

About to drop a Mountaineer motor in too so I'm curious what comments you get about the cam.

Keep us posted on your progress.

What do you plan to do with the Bronco?
Horses for courses.
 
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Cooter_76

Cooter_76

Sr. Member
Joined
May 18, 2004
Messages
863
What do you plan to do with the Bronco?
Horses for courses.

Cruising with the family and some mild rock crawling/trail riding. Eventually planning to run 33's and 4.56 or 4.88 gears. Currently 32's with 3.50 gears.
 

sykanr0ng

Bronco Guru
Joined
Aug 11, 2014
Messages
5,363
Cruising with the family and some mild rock crawling/trail riding. Eventually planning to run 33's and 4.56 or 4.88 gears. Currently 32's with 3.50 gears.

For that purpose and with the original engine size I would keep the Explorer cam.
It is a fairly good torque cam and was used in all the late 302 and 351W truck engines (except the F150 Lightning).
 

Teal68

Contributor
Bronco Guru
Joined
Mar 28, 2013
Messages
2,566
Loc.
Inlet Beach
What do you plan to do with the Bronco?
Horses for courses.

I drive mine a lot on the street. It's pretty much my driver unless it's raining or too hot out. I'm adding air when I swap the motor so I'll be doing even more street driving with it. I do some decent wheeling about 3 times a year, and also hit sand trails near me whenever I get a chance.

Here's where I'll end up: 2001 roller motor, carbed for now, duraspark, NV3550, 3.50 gears, and 33's. I'm in the flat lands of FL so I don't think the gears will be a problem, but I'll re-gear if need be. I don't mind driving 75 MPH so it would be nice to get the RPM's down some.

Thanks for the input,
Tyler
 
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