Is the stock 4.0 pushrod worth beefing up?

[Town&Country808]

Move me if this post belongs in a different thread or advise me if this question has already been addressed. Ive just purchased a '91 explorer xlt and the motor has 70k original miles but I opened the intake to do some gasket replacements and it looked nasty I cleaned it best I can.probably gonna sea foam it. Anyhow it seems pretty gutless, wondering if this motor is worth building or if I should follow my dreams on going v8 swap. Any suggestions on this or personal experience would be appreciated Thanks. BTW I have a 5spd manual with the manual locking hubs.

 

[Jason94sport]

91 with 70K miles? You SURE about that?
And how much you have to spend? You can build it spend a ton of $ & still be on the lower end.
There are a few that have built them up & it costs $.

 

[Town&Country808]

It was an airport security truck auctioned off and it was one owner that explains the low miles, but I'm really thinking I'll just huntil down a 5.0 to swap in.

 

[jd4242]

Yea id question the mileage also especially since they dont have a 100k+ reading. .low mileage old trucks can be even worse than a high mileage motor..other than head issues the ohv is about the most reliable motor made..the bottom ends I've seen look brand new well over 200k+

What gears and tires does it have??putting the power down makes all the difference. .with the right gears and 5speed it shouldn't feel gutless. .but you can rebuild them for not all that much and get power but takes big money to make decent power(over 300)..but the ohv not about hp,its a tq motor.

If the motor truly has 70k id just do a 98tm head swap with a 422 cam..that is about cheapest best bang for buck..then give it hell for another 200k+

 

[Rhett]

What was said...plus if it really only has 70k on it, I would be less inclined to swap that out. You can't fade the funk of 225 foot/lbs of torque in our OHV V6 engine...that rivals your typical V8 swap torque...

 

[Town&Country808]

Mines pushrod not ohv I think that's where everything goes wrong lol, I got 29's I believe and stock gearing at 3.73

 

[jd4242]

Mines pushrod not ohv I think that's where everything goes wrong lol, I got 29's I believe and stock gearing at 3.73

The ohv is the pushrod..and whats the door code??

 

[96EXXLTinCO]

Where do these 98tm heads come from? I think this is the first I've heard of them.

 

[jd4242]

Where do these 98tm heads come from? I think this is the first I've heard of them.

They are for a 98 explorer. .lol its a cast number..im referring to aftermarket 98tm cast heads..90tm and 93tm heads used from 90-94 are known for cracking..the aftermarket heads are thicker cast and solve this issue making the ohv even more reliable. .

The 98tm heads have a smaller CC so when used with 90-94 pistons it raises your compression to 10:1 when combined with a cam like the comp cams 410 or 422 it makes for nice gains and a more efficient motor..

The 422 being the better more powerful cam..to run either cam you need comp cams 988 duals springs,spring seats milled to a installed height of 1.6 and longer pushrods from smith brothers around 5.550..

i also suggest SI one piece stainless steel valves,the stock ones are 2 piece and can break with the added pressure from springs..they also flow better..but to use SS valve you need to have bronze guides installed in the heads..stock heads have cast guides and they will wear and stick to the stainless valves..

Thats a 98tm and cam top swap..best bang for your buck..add in a Efan and UDP to top it off..anything else isnt worth it..proper gearing is crucial, if your not geared right your pissn in the wind

 

[96EXXLTinCO]

Damn!! I was starting to wonder where that was going to end!! I'm pretty sure our 94 has a cracked drivers' side head, leaking coolant under the head, and the plug closest to it had a green tint and was way more fouled than the others', so of course I was hoping it was a little easier I know youve got quite a bit of experience with these motors, so in your opinion, how bad an idea is it to keep running it? It's been down for other reasons since January but we just got the final parts yesterday to put it back on the trails. I don't want to see a catostrphic failure in the middle of a hairy obstacle, especially since this is the ole lady's rig!! But if it's not gonna hurt much I'd rather just run it.
Another question for you though JD, do you have a reccomendation for a decent but not break the bank electric fan(s)? My 92 has a 3" BL and you know what that does to the shroud, and she runs just a touch warm from time to time so Ifigured an E fan would be my best bet. Side note, I think I came across some youtube vids of your rig just last night possibly? If so, I love it!!
Sorry so long, and if we do decide to add some extra oomph, Ihope you wouldn't mind me picking your brain a little?

 

[Town&Country808]

Forgive me for not knowing haha I'm only 20 and this is my first truck that I'm actually getting hands on and wanting to build. I'll check the code and get more info for sure

 

[96EXXLTinCO]

If you dont already know, the door code JD is referring to is the sticker on the inside of the drivers door. There is a spot at the bottom that says axle and then a number, or a letter and a number. That's the code he was asking about. Apologies if you already knew.....

 

[jd4242]

Damn!! I was starting to wonder where that was going to end!! I'm pretty sure our 94 has a cracked drivers' side head, leaking coolant under the head, and the plug closest to it had a green tint and was way more fouled than the others', so of course I was hoping it was a little easier I know youve got quite a bit of experience with these motors, so in your opinion, how bad an idea is it to keep running it? It's been down for other reasons since January but we just got the final parts yesterday to put it back on the trails. I don't want to see a catostrphic failure in the middle of a hairy obstacle, especially since this is the ole lady's rig!! But if it's not gonna hurt much I'd rather just run it.
Another question for you though JD, do you have a reccomendation for a decent but not break the bank electric fan(s)? My 92 has a 3" BL and you know what that does to the shroud, and she runs just a touch warm from time to time so Ifigured an E fan would be my best bet. Side note, I think I came across some youtube vids of your rig just last night possibly? If so, I love it!!
Sorry so long, and if we do decide to add some extra oomph, Ihope you wouldn't mind me picking your brain a little?

I wouldnt run it but thats me..especially depending on where the water is going..double check your lower manifold bolts,they like to come loose

I use the fan from a supercharged tbird..it fits very very nice..it uses same fan as the Taurus fans but has a smaller shroud and different blade design to move more air. .they are getting harder to find tho and lots of people say they are for the supercharger model but they arn't, there is a huge difference ..i then use a flexalite 33504 controller..its a soft start and runs a 60% at set temperature. .10* above set temperature it goes to 100% power and runs up to 30 sec after shutoff.

I run this setup on all 3 of my trucks..

This is the fan

And on the ohv radiator

 

[jd4242]

Forgive me for not knowing haha I'm only 20 and this is my first truck that I'm actually getting hands on and wanting to build. I'll check the code and get more info for sure

O no i wasn't giving you a hard time,we are all here to learn or share our knowledge and experience

 

[Town&Country808]

No haha I know you guys aren't giving me a hard time I appreciate all the feedback, actually I just replaced my intake gaskets and head gaskets clrated the motor up some and put some injector cleaner in my fuel and now it's like the motors alive! I just need to replace the fuel return line connected to the top of my fuel pressure regulator it's leaking

 

[Rhett]

% at set temperature. .10* above set temperature it goes to 100% power and runs up to 30 sec after shutoff.
I run this setup on all 3 of my trucks..

This is the fan

Do you run the OEM shroud with that fan?

 

[jd4242]

Do you run the OEM shroud with that fan?

No i run it as pictured

Edit.. as in the shroud thats around the fan and what came with the efan outa the tbird yes...

No i dont run the explorer OE fan shroud over that fan setup