4.0 Rebuild to increase HP\HELP?

[ricky_dicky_doo]

hey im looking to rebuld my 93 explorer 4.0L. looking for tips and pointers on doing this. I have a rebult transmition in this already so im not looking fowards in doing a v8 swamp. it would be grater to get maybe get another 100hp or more out of it at a resanable price and it has to fit under the hood. links and other sorces will be greate as well.

 

[Creager]

haha 100 hp would be nice wouldnt it?

going to be impossible probably (on a first gen platform atleast).

only way to do it, cheaply... would to get a complete 4.0 OHV motor out of a 96-98 with OBD-II, swapping in computer and all the sensors.

then you could put ALL the bolt on mods ($1000, throttle body, MAF, nice set of headers)

a nice cam (check summit racing for Comp cams 410 and 422 cam) ($250)
then you need a custom set of pushrods for this cam ($100)

Port and polish heads and lower intake... match gaskets ($600)

Overbore block (wouldnt do much for power, but definatly would be cool)

and there you have it. maybe a 50 hp increase? for... $2000?

then the REBUILD kit is going to cost $1065...

$3065

sure you dont want a v8? haha

Oh then you need a chip (whole reason behind going 96 motor, OBD-II) $400

total ~$3500 to have yourself a v6 with v8 power.

from there you can try a super charger, and nitrous of course... that ill get ya that 100 hp for sure.

 

[ricky_dicky_doo]

thanks for the help im going to have to think about it.

 

[unclemeat]

It seems to me the best way to max HP is open up the intake and exhaust and add a supercharger or nitrous oxide or both.

 

[Captain AirTime]

It seems to me the best way to max HP is open up the intake and exhaust and add a supercharger or nitrous oxide or both.

Turbo/SC/N2O. Forced induction is the only way you're going to get another 100HP out of it and keep it drivable and reliable, IMO, and even then I'm not too sure how strong the head gaskets/rotating assembly are in the 4.0L. It would be better to swap a V8 and new transmission anyway. 2-3 grand for an Explorer 5.0L w/trans, another G for adapter and misc. None of its cheap, but the potential of the 5.0 is far superior.

 

[Ronin8002]

The headgaskets and rotating assembly of the 4.0 OHV can support at least 250+ HP with no changes made. If you want to make the bottom end stronger, have your crank shot peened and heat treated. The rods are very good forged steel pieces....not much you need to do other than replacing the stock rod bolts with ARP 289/302 rod bolts...they will work fine and be a great deal stronger than the stock rod bolts. You could also grind off the balance pads and casting flash from the rods but it would not be essential. Shot peening the rods would also be a good idea. Lastly, get a set of hypereutectic or forged aluminum pistons...the stock pistons are pretty much the weakest part of the bottom end.

If you want 100 extra HP, you'll need to open up the intake, have your heads ported, get a good cam, use headers and a high flowing exhaust, and use a dry nitrous kit with a 50-75 shot. That will give you plenty of power and a ton of extra torque for the least amount of money. You really wouldn't need to touch the bottom end unless you're rebuilding anyway or you have over 160k miles or so. I know of 1 guy with a 94 ranger who was spraying 75-100 shots of nitrous on his 4.0 for a long time....up to 135k miles and when he took it apart everything looked really good on the inside still. He was very careful about keeping the fuel mix good and not going lean....that will kill you more quickly than having too much power.

 

[Creager]

Anyone ever used 'Sealed Power' piston rings (on their 4.0)?

 

[mtadd162]

hey guys, had a question about that whole cam and pushrod thing...im takin my engine out but unfortunatly its for oil leaking problems so were're gunna re-seal the whole thing, and while it was out i was going to put a cam in it (specifically, http://store.summitracing.com/default.asp?target=partdetail.asp&part=CCA-49-410-8&FROM=MG) now it was either that or headers, so i decided on the cam, anyway with this cam its not neccacry to get a custom set of pushrods, right?...And if you have an opinion on if u think headers is a better way to go, lettme know, cause i havent exactly writtin it in stone yet.

 

[Ronin8002]

If you are using the stock rocker arms (not modified in any way) and stock heads you will need pushrods in a length of 5.550". You can keep the stock valve springs if you use that cam though. Go to www.pushrods.net to get these made....they have done many sets for guys who have upgraded cams in their 4.0 so they should have some idea of what you need.

Either cam or headers are good mods alone. It's easy to open up intake or exhaust or do headers but the cam is really the heart of a motor and controls how and when it breathes....everything else just supports the cam. I would do it first and then do headers....or gather parts and do em both at the same time.

 

[Jeffbethandkidz]

Hey, I hate to highjack the post, but I have a question about the connecting rod bolts. Maximum Violence, you state that the 289/302 rod bolts will work in the 4.0 Ohv. Do you know this for a fact, or is it just something you have heard. I ask because I'm trying to find replacement rod bolts for my build up and have not had any luck finding any rod bolts. It would be great if the 289/302 ones will work, I'll order mine right up. Thanks again guys.

 

[wood1]

hey im looking to rebuld my 93 explorer 4.0L. looking for tips and pointers on doing this. I have a rebult transmition in this already so im not looking fowards in doing a v8 swamp. it would be grater to get maybe get another 100hp or more out of it at a resanable price and it has to fit under the hood. links and other sorces will be greate as well.

STS makes a universal turbo kit that would get you a nice increase in hp. If I had a fresh engine and transmission that's what I would be doing...

 

[seth247]

the above suggestions are all good but if you want to keep it 4.0 and nonboosted here's a good list

Air intake. Ifab makes the only full tb to filter intake I know about.(140$ on sale right now) Or just a maf to filter adapter(10$ ebay) and a k&n cone filter(40$ summit) some have used PVC for the intake tube but it won't fit everybody.

Exhaust. I suggest the flowmaster super 44(89$ autozone,summit. check my sig) I love it, but whatever muffler brand you like is best. A shop did my duals for 70$ but most places are higher. You can get a full flowmaster side exit exhaust from summit for 189$ I had it its fine if you don't like too much noise.


Camshaft. Comp cams 410/ 422- (220$ish summit) you wouldn't believe how restrained the stock cam is (stock intake and exhaust lift is only 0.255!!! Comp is double that)

Block. Over bore (pick your amount) requires new pistons. Price varies. Talk to your mechanic they should know somebody.

Heads. I think Alabama makes heads for the ohv can't remember the specs on them or price

Port heads (I've been told polishing not really necisary) price varies

New pistons. If you feel like it. (summit) good idea if you have further plans.

The above will get you plenty of giddieup. not sure on hp gain numbers.

 

[seth247]

But over all man. With the amount of money I'd say save it and buy you a mustang. If you keep looking you CAN find a deal.

 

[91exploreron37]

You could do all that and a turbo kit

 

[seth247]

You could do all that and a turbo kit

Yes there is always the "win the lottery" option as well.

 

[zsmitty81]

Hey, I hate to highjack the post, but I have a question about the connecting rod bolts. Maximum Violence, you state that the 289/302 rod bolts will work in the 4.0 Ohv. Do you know this for a fact, or is it just something you have heard. I ask because I'm trying to find replacement rod bolts for my build up and have not had any luck finding any rod bolts. It would be great if the 289/302 ones will work, I'll order mine right up. Thanks again.

Hello, I’m in the same position with my 4.0 OHV. I have some stretched bolts and need to replace them. ARP makes them for the 2.9 (153-6001) and then the mentioned ones for the 289/302. Summit racing tech service was no help and wants measurements. Does anyone have input on which bolts work well for sure. I know the SOHC are TTY bolts so they’re more readily available. Will they work on the OHV? Thanks, Zack