Need suggestions for refresh

[colintrax]

Hey y'all, I'm giving the old explorer a refresh/rebuild. Got a 4wd explorer to make mine 4wd. (BTW Rick, I'm trying to get the elite membership but the link is inop) and will be parting out what's left.
The end goal is to make the explorer more capable and sensible for camping, road tripping, and so on.
My truck is a 97 with the 4.0 OHV, auto, 2wd with 3:73 rear end. Donor truck is a 98 4.0 SOHC, auto, 4wd with 3:55 gears.
My truck has a little over 200K miles. Leaking oil, runs a little rough, and just feels down on power. I'm thinking of pulling the heads, putting in fresh rockers, rods, pistons/rings. While I'm at it I'm considering some more port work, cam, tune, maybe even going as far as a turbo. What's the consensus for building a fuel efficient, reliable motor out of the 4.0?
I got everything for the trans, just needs the 4wd output shaft put in.
Gears? I won't be using the front pumpkin from the donor truck since it's effing 3.55. So I'm looking for a 3:73 to match my rear. Or should I suck it up and buy 4:10 front and rear from the salvage yard? Tire size is currently 31" but I'm playing around with going down to a 30 or up to a 32. I really don't know what tire size I want. Ok I do, but I don't know I want to go through the effort and fuel costs of 33's lol any opinions here? I'm not trying to run crazy trails. Just the mild stuff.
I want the auto 4wd to work, and all the dash lights to work with the 4wd. Am I going to have any problems swapping stuff around since the donor truck is a SOHC?
I'm considering a body lift (again) so any opinions here? My biggest concern is the rad fan. I could go electric but that's more work, and I question the reliability. Lowering the rad could work, but I don't like the idea of getting the rad closer to the ground in relation to the body)
Suggestions for cams, rockers, tires, gaskets to get or avoid, etc etc is much appreciated. I haven't been around here much lately, so I'm a bit out of the explorer loop.
Thanks!

 

[colintrax]

Also meant to ask about exhaust. Advice on headers? It needs all new pipe ran from the cat, might as well replace whats ahead of that cat right?

 

[Mbrooks420]

If you are going to with 30s I wouldn’t bother going with the 4.10s. The only upside to the 3.55s is you could lock it for pretty cheap.

The 4.0 isn’t the easiest motor to make power out of. A mild cam, ported and polished heads and a tune is probably your most reliable option.

 

[shucker1]

Donor truck is a 98 4.0 SOHC, auto, 4wd with 3:55 gears.
My truck has a little over 200K miles. Leaking oil, runs a little rough, and just feels down on power. I'm thinking of pulling the heads, putting in fresh rockers, rods, pistons/rings. While I'm at it I'm considering some more port work, cam, tune, maybe even going as far as a turbo. What's the consensus for building a fuel efficient, reliable motor out of the 4.0?

I'm not a 4.0 expert but from everything I have read don't forget to do the chains while its out.

 

[boominXplorer]

The trans is not a direct part number swap but should work. It's a 5r55e and yours is a 4r55e. Technically they will plug in and work the same but you will still just have the 4 speeds. You will have to find a tcase with a speed sensor though since that 98 won't have one and your 97 pcm will want to see it.

 

[Mbrooks420]

If I read it right, he’s not using the trans, just swapping the tail shaft. Would they be compatible between the 4R and 5R?

 

[boominXplorer]

I recently had a similar deal with a trans trying to use a 00 trans in a 96. I had to get and use 97 parts in the 00 housing to get it right. This was on a 4r44e so I'm sure it's similar. It should work but its alot of work and honestly I'd swap that 98 trans in first if it's good. The valve body harness is the same 95-01 and the only other thing that changed is the range sensor.

Here's my thread I had to give you an idea what your up against Calling transmission guru's 4r44e output shaft interchangability

 

[CDW6212R]

Stick with the 4.0 OHV, skip the SOHC, not worth the trouble(go to the 302 etc, before doing the SOHC).

The 1997 Explorer transmissions are a bad model year to work on, I knew a Ford mechanic who learned that the long and hard way. His wife's Explorer took him several weeks to fix, he tried a 98 or 99 trans, then had to go back and fix the 97.

So keep that original transmission in place as long as you can, rebuild everything it might need. The 4WD output shaft and housing extension may work, but I'm thinking the shaft won't have the needed speed sensor in it. If it does, you should be good there.

If I had issues with a 97 trans, I'd either fix it to original parts, or swap to a 98 wiring harness and trans, to get away from the 97 trans(it has some extra sensor that no other models had(that's what I was told)).

 

[colintrax]

Sorry guys, I guess I wasn't clear. The transmission in my truck (the 97) is all already built up. Upgraded bands, shift kit, deep pan.
The 98 donor truck has a bad trans, first gear is out and others are slipping so bad it'll only drive in 4low. I'm just simply pulling the shaft from this one, and putting it in my 97 trans.
Boomin afaik my 97 is a 5r55e. So the shaft ought to go straight in. I'll double check later though

 

[colintrax]

Also I have absolutely zero interest in the SOHC engine. It runs but the chains are slapping. With 255,x.. miles it won't be running much longer. An engine swap would be a 5.0 or 4bt. Not sure I have the time for those though. Need the explorer done by June, and I got school and work during the week.

 

[CDW6212R]

Sounds good, you've heard of the issues of the SOHC etc.

 

[colintrax]

Friday I'll start tearing down my explorer. Right now the idea is new oem pistons/rings, oem (ish) rockers, 410 cam, mild port work, new cam chain, high flow oil pump, reworked intake, jba headers, stock cat, custom exhaust cat back. Assuming of course everything else looks good. Any suggestions, concerns so forth? Or am I on the right track?

 

[CDW6212R]

Sounds decent, I'd change the ATF again, and buy a deep pan for it too. Extra ATF is good, runs cooler and there's less breakdown of the fluid from heat etc.

 

[colintrax]

Got a deep pan, and new fluid is def def coming with the tear down lol

Btw who's the go to tuning guy these days? Seems bamachips ain't around anymore

 

[colintrax]

Finally got around to making my cart on rockauto. Am I missing anything here? I think I'm going to order Ford rocker so those aren't in this list for that reason. Also not sure what length push rods I'll need. I know everyone says 5.500 with the comp cam but I'm gonna need the head shaved with the reduced height pistons. Likely .02" so 5.480 rods assuming I'm correct here.
Upper engine gasket kit (heads, exhaust, intake)
Melling HV oil pump
Cam bearings
Connecting rod bearings
Lower gasket kit (oil pan, timing cover)
Crankshaft bearings
Crankshaft "vitol" seal
Intake and exhaust valves
Pistons/rings
Timing chain, guide, and tensioner
Valve seats and springs
Head bolts (felpro)

Mods bought or going to be bought.
SOHC oil pan
SOHC MAF
comp cams 410 cam
JBA headers
Stock intake is already cleaned up, I might do some more port cleaning/porting. Heads will get some port clean up.
Tuner to make this work?

 

[CDW6212R]

Buy a normal oil pump, high volume is for racing high rpm only, with special large clearanced journals machine for it.

Wait until you have the heads on the engine before ordering pushrods. You want then exactly the right length, which takes measuring of the parts assembled. No two engines are the same. Buying pushrods very close to what you need is not much more expensive than an OTS set.

 

[colintrax]

Buy a normal oil pump, high volume is for racing high rpm only, with special large clearanced journals machine for it.

Wait until you have the heads on the engine before ordering pushrods. You want then exactly the right length, which takes measuring of the parts assembled. No two engines are the same. Buying pushrods very close to what you need is not much more expensive than an OTS set.

I've seen nothing but good things about the mellings m238 pump, should only be beneficial right?

Yeah I'm just gonna wait to order pushrods. I'm not sure how much the head is gonna be decked anyways.
Thanks

 

[CDW6212R]

Melling makes great oil pumps, I've used a few since my first Cleveland in 1980. Is that for a 4.0, the one I found didn't mention Ford, and was $73 at Summit?

 

[colintrax]

Sorry! 328. $73 would be awesome though, rockauto has it for ~$130

 

[bigred4x4]

Unless your stuck on the 4.0 I rebuilt both my 4.0 engine stock with no performance upgrades and a few upgrades and updates on the 4r55e trans, if I had the money, since your pulling the the engine and trans any way I'd swap in a V8 drive train, with all the upgrades on the engine id be surprised if it ends up matching or surpassing the power of the stock 5.0, plus throw in a 4406 manual t case from an f150 and your good to go, I'd get your heads checked on the 4.0 as well if you stick with that, 32 " I think Is a good compromise between 30/31 and 33's it does fine, not great, but fine with 3.73's and very capable off-road. Body lift and TT plus .... Instead of shackles id look into ARB old man emu lift springs for explorer as I'm sure your tired leaf packs will go flat with shackles pretty quickly. Also I found #1 torsion bar swap was the way to go for me because the B bars wouldn't hold the lift for very long. And actually rides better.