4.0 pefromance rebuild

[skinner]

Long time no see Bird...
good to see you still lurking around...
Will you PM me your contacts...I plan on building a stout little 4.0 OHV once this anemic 3.0 eats itself(keeps eating head gaskets...and pouring more money into it is like sponsoring a 350 lb sprinter)

 

[woodyedmiston]

94redranger & ranger 44

As for the compatability of the heads vs. the new/older heads and computers of opposite ages. I'm not advocating that you go ahead and do that without checking it out. I'm just amazed at how often that single line in the Doug Anderson article seems to be referenced. It doesn't make sense to me - but I'm willing to learn. I was hoping someone would know the answer. My orginal question related to experience, Ranger 44 and hoped you had done it previously and could supply info from your work with your Ranger.

I too am going to rebuild a 99 Ranger lower end and . . .since one or more of the heads is cracked . . . I'm interested in a head swap or mod that might make some difference when it goes back together. But I'm not interested in experimenting with $$$ as you suggest. But . . . I'm hoping 85_ranger 4x4 is correct in saying that some tuning will make whatever I screw together stays that way.

On the other hand, 94 redranger . . . lt me suggest something - lightweight parts do not generally add horsepower. Imagine a 4.0 motor built with parts that were so durable they just couldn't within reason be destroyed - they would make the same horsepower - it would just take longer to get that horsepower created and ready to be used. That's why tractor parts are rugged, durable and work for long periods of time. But, they run low RPM, they are heavy, and are engineered to make most of their horsepower in that rpm band. Lightweight parts allow you to spin up the motor faster for drag racing applications or coming off of a tight turn in a road racing application. There is a "magic" piston/rod/bore number that relates to RPM and moving the HP range into the higher rpms. You'll read about it in engine building magazines. However, a small, say 4 cyl. turbo high revving engine, with a lightweight flywheel that makes 480 hp @ 9000 rpm will scream on the straight away but a V8 Chevy with the same wight and hp (480 @ say 6000 hp) will have the advantage coming out of a tight turn on a road course. The smaller, lighter components, like a flywheel for instance can make a care it difficult to drive - especially on the street - with a shift shift. But again, you have to have forged pistons and good rods if you are going to wind an engine to higher rpm for long periods of time or you are adding boost - but if you want to drive your 4.0 on the street, do burnouts, and have fun with your truck it's a lot of money to spend.

I'm still interested in hearing from someone who has experience with the newer computer older heads thing.

 

[Yellowsplash]

As for the compatability of the heads vs. the new/older heads and computers of opposite ages. I'm not advocating that you go ahead and do that without checking it out. I'm just amazed at how often that single line in the Doug Anderson article seems to be referenced. It doesn't make sense to me - but I'm willing to learn. I was hoping someone would know the answer.

Well....a ~10.0:1 compression ratio isnt that much of a jump from stock (9.0:1). The problems associated with higher compression is detonation. Rbvs dont have the most amazing spark timing base map to begin with, so the threat of being too far advanced shouldnt be an issue. With higher octane gas, you definitely shouldnt have a problem. Remember, the SOHC engines have a 9.7:1 cr straight from the factory.

There is a "magic" piston/rod/bore number that relates to RPM and moving the HP range into the higher rpms.

The cam does more for the power curve than the bottom end. Yes, a stroker engine will produce higher torque numbers down low compared to a stock engine, and at the same time a shorter stroke is better for a higher revving engine. Unfortunatly, we are referring to a 4.0, not a v8. No first hand stroker experience, atleast on this board. Either way, the cam is still more influential in this aspect.

However, a small, say 4 cyl. turbo high revving engine, with a lightweight flywheel that makes 480 hp @ 9000 rpm will scream on the straight away but a V8 Chevy with the same wight and hp (480 @ say 6000 hp) will have the advantage coming out of a tight turn on a road course.

One word, torque. The 4 cylinder has to "spool" up his turbo in order to make his power whereas the v8 just punches the gas and watches the speedometer climb while the gas gauge drops... Having 4 extra cylinders firing per revolution helps atad with throttle response. If the 4 cylinder could keep his engine in the power curve, you'd be suprised how quick they can be. My buddy has an eclipse who puts out 864 hp at 42 psi... It'll run 9's all day and still drive home.

I'm still interested in hearing from someone who has experience with the newer computer older heads thing.

You got that alil backwards....its newer heads with an older (OBD I) computer and block.

 

[86_cookiemonster]

The cam does more for the power curve than the bottom end. Yes, a stroker engine will produce higher torque numbers down low compared to a stock engine, and at the same time a shorter stroke is better for a higher revving engine.

There is an old hot rodder trick, I bet most of you are familure with. You take a 350 chevy sb (or any v8, I just know this one) and you de-stroke it down to a 305 (or what ever displacement you would like). The 350 chevy has a larger bore then the 305. SO by destrokeing it you where able to built the same power as a 305, but you could rack the rpms a lot faster.
I believe they also did this the big blocks. But I am not sure. I have heard of taking a 427 down to a 350 or a 302, but never seen one.

I wounder if you could do somthing similar with the 4.0 OHV. Take the 4.0 block, and use a 2.9 crank and rods. That would be interesting to see.

 

[Yellowsplash]

I wounder if you could do somthing similar with the 4.0 OHV. Take the 4.0 block, and use a 2.9 crank and rods. That would be interesting to see.

Actually, AllenD has had this idea for a while...

 

[86_cookiemonster]

Actually, AllenD has had this idea for a while...

Really. I figured someone had beaten me to the punch. But yea, i wounder how well that would work, or if anyone has done it.



I don't even know how you would search for somthing like that lol.

 

[94redranger]

Ok so here is my build plan with a few questions.
1. 0.020" overbore with clevite hypereutectic pistons
2. '95-'97 heads. What should I touch and leave alone when porting and polishing these heads?
3. Comp 422 cam and extended pushrods. With this cam will I still be able to drive comfortably from 1250-2000 RPM?
4. 66mm t/b and headers.
5. Where can I find a good performing crankshaft and rods or will the stockers be just fine?
6. After all is said and done will I have to get a custom made chip for the higher comp ratio and cam? Will I need new higher flowing injectors?

 

[MAKG]

You forgot

0. Run this whole thing through a desktop dyno.

It's a SYSTEM, and throwing a bunch of parts together is likely to give you a bunch of expensive parts on an engine that performs close to or worse than stock.

This will tell you if you need higher flowing injectors. If you can't CALCULATE the answer, you have no idea if this combination will work. Same deal with that 66 mm TB. And it will tell you the detonation limit AND the cam you need (hint: you have a higher than normal CR, which means you may need a retarded cam, or at least a late intake valve closing event -- this setup doesn't do you any good if you need 100 octane to keep from detonating at 3000 RPM).

 

[Yellowsplash]

For p&p the heads, check out what bird has said in the other thread. (hint: bowl area and the port roof)

http://www.therangerstation.com/forums/showthread.php?t=24491

If your worried about low end power, you might just want to go with the 410 cam. While either cam is going to make its peak torque in the 2500-3000 range (2400 is stock), the 422 is going to pack more of a midrange range and pull harder up to just over 5 grand.

Another thing to remember is that with the 422 cam, you will need upgraded valve springs to handle the profile and additional lift.
And for the extended pushrods, you'll need 5.525" if the head has been milled, 5.550" if the deck surface/head are relatively stock (or just minor cleanup).

Since your rebuilding it, use a SOHC oil pan because of its built in stud girdle. This will help reinforce the bottom end a bit....anything helps.

I would look into the Delta Cam rocker arm kit with the hardened pushrod sockets. Dont want that badass engine to "tick".

For the most part, you probably wont need upgraded injectors, but I would steal some 24 lbs/hr injectors (19 lbs is stock) from a SOHC in the junkyard. In order to run the bigger injectors, you will need a C&L 73mm MAF with the appropriate sampling tube calibration for the 24 lbs injectors. This is a win-win situation as your allowing more airflow at the same time. DON'T EVER USE A PRO-M OR ANY OTHER CALIBRATED ELETRONIC MAF!!! They suck and throw the engines electronics for a loop.

I would also lightly polish the intake side of things, NOT port, but polish just to get any casting marks, etc.

Stick with JBA headers as they are the best...

ARP rod bolts from a 5.0 would help the bottom end. Bird can chime in on this...

Add these to the list....
Smith Brothers Pushrods - NR54A-A 5.550" www.pushrods.net
Comp Cams dual valve springs - pn 988-12
Crane Cams valve retainers - pn 99947-12
JBA headers

Optional....
SOHC oil pan
SOHC 24 lbs injectors
C&L 73mm MAF w/ 24 lbs sampling tube
ARP rod bolts

All this information was taken from hours of searching on various forums. Props go to bird and doug as they know their shit...

 

[94redranger]

Ok I think I'll go with the 422 cam the 410 just has lower operating range and makes more bottom end power, right? So if I keep my stock injectors and MAF will it run fine with that setup? With the cam and new heads will I need a tune or could I tell Doug at BAMA chips what setup I got and he would know what I need? If I didn't tune could I still drive it, I just wouldn't have the most potential horsepower from my motor?

 

[Bird]

Pretty good compilation of data there, Yellowsplash. The 24# injectors from the SOHC will require adapters as they use the EV-6 connector and the 4.0 OHV's use the EV-1 connectors. Also, Crane no longer makes the 99947 retainers, but I have heard that the retainers for the LS1 engines work as well or better.

Bird

 

[woodyedmiston]

Way to go Yellowsplash

Yellowsplash,

You've said a great deal that seems to make sense - tell us where you got all that info - got pictures of what you have/are building. I'll copy some of this thread and put it in the back of my Ranger book. On my last look I missed some comments on page two that were helpful.

Someone said something about getting it backwards - not everyone wants to raise compression - some people want lower static compression with a lot of swirl for turbo or blown applications. So - any way you can use stock parts and get a system that works is cool.

MAKG said some interesting things too - but I usually have to take his comments to someone who actually knows something about tuning for the interpretation - thanks to you as well. Thankfully, my daughter is an engineer so she can help with the math.

 

[Ranger44]

Just the heads will give about 10 rwhp, but you'll be needing higher octane fuel. Get them properly ported and polished and you'll pick up another 10 rwhp - at this point, you might as well throw in a cam (Delta Camshafts has a decent regrind at a good price or you can go with Comp Cams for a lot more $$$), longer pushrods from Smith Brothers and a good tune and you'll be around 185 rwhp with a pretty nice low end torque curve.

And before anyone asks - yes, I've built a couple of these motors just like this - very fun to drive.

Bird

So you need to run higher ocatne to use the heads or to yeild the power?

 

[Bird]

So you need to run higher ocatne to use the heads or to yeild the power?

Higher octane to help prevent detonation - if you're in higher altitudes, you may not necessarily need the higher octane. The higher compression will create the extra power as will increasing the flow through porting, etc.


Bird

 

[MAKG]

If you're going to higher octane anyway, wouldn't you get quite a lot more HP/$ by just advancing the timing curve and doing nothing else? That can be done for the cost of a tuner. Sure, it won't make the engine as powerful as it could be, but I really doubt the strategy at hand will either, as it's going to be killed before it's complete by budget and/or lack of expertise. The approach suggested here is very expensive, especially when the results come back short and it needs some more physical modification (custom cam grind, a bit more off the deck for compression, etc.).

As a rule of thumb, at higher altitudes, if you needed premium at sea level, you need premium at high altitude. They aren't the same octane numbers; there is more octane at the lower altitudes for a given "grade" of fuel.

For standard-grade pump gasoline, 87 octane is at sea level, but it's 85 or sometimes even lower at altitude.