4.0 OHV V6 light performance "optimization" build

[KevinSonOfDad]

Looking for any advice on a build I'm looking to do. My rangers stock 4.0 is getting pretty worn out at almost 250k miles. I'm looking to get a junkyard engine and rebuild it in my spare time (I work a full time job as a engine machinist so i have access to the equipment) I'm mainly looking to "optimize" the performance rather than boost it much. In saying this I mean things like improving factory flow with a port and polish as well as upgraded heads. what other mods would you all suggest? looking for closer to 200hp than 100 . I have considered maybe the 410 or 422 cam: what other mods would have to be made to accommodate those and what are the benefits of each.

 

[KevinSonOfDad]

Im pretty sure about the 422 cam at this point as it seems it doesnt have much of a downside compared to the 410. I am still unsure if stock valves will work? any info about that?

 

[Shran]

I think the stock valves will work but some guys had to run double springs with the 422 cam or something to that affect.

IIRC the 95TM heads are what you will want, if you can find them.

My buddy built a 4.0 that was bored .030 over and had some other style piston in it (think SOHC pistons maybe?) and 93TM heads, otherwise totally stock with a small increase in compression from the pistons. Really made for a nice running engine.

 

[KevinSonOfDad]

I think the stock valves will work but some guys had to run double springs with the 422 cam or something to that affect.

IIRC the 95TM heads are what you will want, if you can find them.

My buddy built a 4.0 that was bored .030 over and had some other style piston in it (think SOHC pistons maybe?) and 93TM heads, otherwise totally stock with a small increase in compression from the pistons. Really made for a nice running engine.

thats exactly waht im looking for just a nice well running engine with a little more power. I was planning on doing dual springs and a full port and polish(some people say for port and polish the 98tm is better?) i had just heard that stock valves are 2 piece and the heads can break off.

 

[Shran]

I am not the most knowledgeable about all the technical details so you might be right about the valves.

Supposedly the 95TM/97TM heads are the way to go with the small chambers and large exhaust ports. I found this recently that was kind of enlightening:

 

[KevinSonOfDad]

I am not the most knowledgeable about all the technical details so you might be right about the valves.

Supposedly the 95TM/97TM heads are the way to go with the small chambers and large exhaust ports. I found this recently that was kind of enlightening:

View attachment 79721

Thats actually super helpful. I do know through my work i can get aftermarket heads that are less prone to cracking. Im pretty sure most of the aftermarket heads are based on the 98tm but if i can get the 95/97tm heads in aftermarket that might be a better way to go

 

[Shran]

I don't think that any of them are really "bad" heads as far as cracking goes except for the 90TM ones maybe. That said I have almost 200k on mine and my buddy down the street has over that on his...still going strong. Cooling system maintenance is just more important IMO.

Where are you finding aftermarket heads at just out of curiosity?

 

[KevinSonOfDad]

I don't think that any of them are really "bad" heads as far as cracking goes except for the 90TM ones maybe. That said I have almost 200k on mine and my buddy down the street has over that on his...still going strong. Cooling system maintenance is just more important IMO.

Where are you finding aftermarket heads at just out of curiosity?

"bad" is relative ig lol. Since i work in a engine building shop we see the most common failures of engines. as a point of reference we have shop cores of heads for almost every head we work on... except the 4.0l because every head we work on has been cracked. not sure the location because its thru the shop but i think its EPWI could be wrong but i do know thats where we get a lot of our parts. i can ask my boss tuesday and update you https://epwi.net is the website link but its something you have to register to have access too. we have been a part of the engine builders association for like 20 years so we do have access to lower prices and websites that most people dont. that said i can easily get pretty much any spec for any of the ranger engines easily for anyone that needs it through PROSIS our shop program.

 

[KevinSonOfDad]

I don't think that any of them are really "bad" heads as far as cracking goes except for the 90TM ones maybe. That said I have almost 200k on mine and my buddy down the street has over that on his...still going strong. Cooling system maintenance is just more important IMO.

Where are you finding aftermarket heads at just out of curiosity?

As a matter of fact if you all would find it helpful i can make a post of the specs (things like valve lash compression etc) for all the engines available in rangers as well as all if any of the TSBs and tips for little upgrades

 

[Ranger850]

As a matter of fact if you all would find it helpful i can make a post of the specs (things like valve lash compression etc) for all the engines available in rangers as well as all if any of the TSBs and tips for little upgrades

@Jim Oaks

 

[KevinSonOfDad]

@Jim Oaks

as well as the 5.0l since thats basically a factory motor option its so popular

 

[Jim Oaks]

As a matter of fact if you all would find it helpful i can make a post of the specs (things like valve lash compression etc) for all the engines available in rangers as well as all if any of the TSBs and tips for little upgrades

Yes please.

 

[KevinSonOfDad]

Yes please.

PSA IF ANYONE NEEDS A SPECIFIC SPEC, MEASUREMENT OR WANTS TO KNOW HOW TO MEASURE SOMETHING JUST LET ME KNOW AND I AM HAPPY TO HELP BOTH PRIVATELY OVER DM OR ON A FORUM POST
i realized after looking today aver the almost 40 years of rangers theres a lot of engine specs lol. Most of them are probably not usefull to the layman that doesnt have the equiptment to measure them anyway. i will start with the 4.0 ohv since i already have all those specs and i will just do basic things like bore specs installed stem height and torque specs. just as a
i will see if i can get the specs for the 4.0 up tonight

 

[KevinSonOfDad]

Posts are both up now and i will be adding stuff later tonight (gotta pack for a canyoneering adventure this week ) as previously stated i will just put down the basics for now and add stuff as people ask for it to save me some time

 

[gaz]

@KevinSonOfDad ,

What is your current OHV 4.0l optimizing plan ..)