4.0 pefromance rebuild

[skinner]

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.

You know, I heard the same crap about my 305 monte carlo. Nothing but a Cam, intake, and headers. People said its a 305 it sucks youre doing nothing. Pulled 205 Hp and 270 Tq at the wheels on a dyno from a motor rated 180 HP and I believe 220 TQ at the motor stock. I had LOTS of good advice beforehand obviously. Bird knows these motors just as the guy I knew KNEW the 305. Discrediting it all is BS. Yes its expensive. Going fast always is.

 

[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.

I havent started building a motor yet, just have spent alot of time researching it. Ive spent numerous hours over the past few years gaining info on various forums (mostly here and rps). As Ive said, lots of my knowledge comes directly from bird and doug, as well as many others who have posted their experiences.

 

[woodyedmiston]

MAKG

Let's go at this from a different direction.

Let's assume that you were given the laboratory task, or proof of principal goal of creating three perfect engines: (1) "hot street" (2) "Rock Climbing and Mudding" - and *(3) "Kick Butt, Grenade Close, Super Gee-Whiz Highest HP" motors from the 4.0 using stock parts whenever possible from any year. Your choice cannot be to just tune a stock 4.0 and do all three -- not that I would argue much with you. BUT . . . for the sake of instruction and full disclosure of your opinion on the matter - what would you do? Be inclusive of all phases and direct us to the formulas you use to calculate any cam,head, piston, fuel combination.

I'd direct the same question to anyone else out there - who works with engines regularly and has real world experience. This has been a good string so far.

 

[MAKG]

I would choose #2, but that wasn't the question I was trying to answer.

And in order to accomplish it, I'd put very high gears in the differentials and leave the engine alone.

If I absolutely HAD to have a more powerful engine, a crate engine swap is FAR more cost effective AND more reliable, since it has actually had more than one made.

Frankly, I'm not going to write a 50 page instruction manual for a desktop dyno. Several folks already have; my favorite is Alan Lockheed's. It's very old, but it really hasn't changed much.

I've done enough engineering work to know that devices built as one-offs very often have unanticipated failure modes, simply because they aren't put through the kind of testing and extended use that a production device must.

I seem to recall someone from the old board successfully built a turbocharged 2.9L, but had a very short lifetime because the wastegate stuck and it detonated to hell.

 

[Ranger44]

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

So this is why they say not to run the newer heads on the older block with older management. The average person would not think to run a higher octane fuel. Therefore it would detonate like an S.O.B. We all know how destructive heavy detonation can be.

 

[Bird]

So this is why they say not to run the newer heads on the older block with older management. The average person would not think to run a higher octane fuel. Therefore it would detonate like an S.O.B. We all know how destructive heavy detonation can be.

Nope - you obviously haven't read the articles or these threads very well - the 'engineers' stated that running the later model heads with the earlier PCM's would create the 'burn down' condition due to the fast burn style head requires less timing - they said absolutely nothing about increasing compression ratio or running the late heads on the earlier short blocks. Very easy to confuse the issues...........................

The swap for compression is something others have come up with and have always cautioned about - if the 'average' person reads about it and chooses to ignore the warnings about the possibility of detonation - they have no business swapping the heads anyway.

Bird

 

[94redranger]

So by installing '95-'97 heads on my '94 block with '94 PCM, I would have to get my PCM tuned for less timing in order for the heads to work?

 

[Bird]

I give up - nobody actually reads and comprehends these days..................



Bird

 

[94redranger]

So by installing '95-'97 heads on my '94 block with '94 PCM, I would have to get my PCM tuned for less timing in order for the heads to work? I am asking again just wondering if what I am talking about will work with no problems?
Another question is about cams. The comp 422 cam operating range starts at 1200 RPM and the 410 starts at 900 I think. Will the 422 make more power at 1200 RPM than the 410? Or does the 410 have more overall low end power than the 422? Does the 410 make more power than stock throughout the entire power band?

 

[Yellowsplash]

Another question is about cams. The comp 422 cam operating range starts at 1200 RPM and the 410 starts at 900 I think. Will the 422 make more power at 1200 RPM than the 410? Or does the 410 have more overall low end power than the 422? Does the 410 make more power than stock throughout the entire power band?

The 410 cam is going to make more power or "torque" down low than the 422 cam. If your going to lug your engine at 1200 regularly, get the 410 cam. You'll be much more satisfied with it as the 410 cam is better for the typical offroader. And yes, the cam will make a nice gain throughout the whole powerband, especially at peak torque.

 

[Ranger44]

Nope - you obviously haven't read the articles or these threads very well - the 'engineers' stated that running the later model heads with the earlier PCM's would create the 'burn down' condition due to the fast burn style head requires less timing - they said absolutely nothing about increasing compression ratio or running the late heads on the earlier short blocks. Very easy to confuse the issues...........................

The swap for compression is something others have come up with and have always cautioned about - if the 'average' person reads about it and chooses to ignore the warnings about the possibility of detonation - they have no business swapping the heads anyway.

Bird

Yes I did read the articles. You also need to understand that I am in the process of learning. I'm here to ask questions and I am able to accept my ignorance on the subject. Remember ignorance is fixable, supidity is forever.

As for the "burn down" issue, thankyou for clearing that up.

 

[86_cookiemonster]

I give up - nobody actually reads and comprehends these days..................



Bird

You can't help everyone.

 

[woodyedmiston]

Although I'm going to have to agree somewhat with cookiemonster, ranger 44 and I are trying to learn something. MAKG is one of the experts on this blog who can - when he chooses to be - very helpful. Redranger94 asked a series of questions about strokers, head/piston interchangeability and what might happen to the compression ratio and engine management system. Yellowsplash and Bird offered some real world and research knowledge about those topics. The next thing you know MAKG and Skinner we are talking about "desktop dynos" and short stroke Monte Carlo's.

Could we go back to the heads, ports and pistons thing?

Before we do, could we agree that - most likely - none of us is involved with an engine development program with one of the racing teams? Most of us are just trying to dink around with parts we have or can trade for and build something a little better - for the sake of the satisfaction of having done it. It's no fun to have someone throw an off-topic fact in about racing fuel or fifth year engineering mathematics when all you are trying to do is learn from someone else's experience about about working on your truck.

The guys who start on these blogs for the first time think what they get back from the membership is the benefit of experience. If you don't have experience - perhaps you ought to mention that it's just your opinion. Sometimes you can tell who the new guy is but that doesn't mean he is fair game and a pop-up target.

If however, you are an 'average' person trying to build the "perfect" engine with parts from Autozone's member's awards points you are on the wrong track - about that MAKG is right. Real engine development takes engineering and cubic dollars. I don't think that is what anyone is trying to do. It would be good for all of us to hear from someone who could talk intelligently about having modified, built and then drove or raced a particular "type" of 4.0 & engine control system, etc.

 

[86_cookiemonster]

Although I'm going to have to agree somewhat with cookiemonster, ranger 44 and I are trying to learn something. MAKG is one of the experts on this blog who can - when he chooses to be - very helpful. Redranger94 asked a series of questions about strokers, head/piston interchangeability and what might happen to the compression ratio and engine management system. Yellowsplash and Bird offered some real world and research knowledge about those topics. The next thing you know MAKG and Skinner we are talking about "desktop dynos" and short stroke Monte Carlo's.

Could we go back to the heads, ports and pistons thing?

Before we do, could we agree that - most likely - none of us is involved with an engine development program with one of the racing teams? Most of us are just trying to dink around with parts we have or can trade for and build something a little better - for the sake of the satisfaction of having done it. It's no fun to have someone throw an off-topic fact in about racing fuel or fifth year engineering mathematics when all you are trying to do is learn from someone else's experience about about working on your truck.

The guys who start on these blogs for the first time think what they get back from the membership is the benefit of experience. If you don't have experience - perhaps you ought to mention that it's just your opinion. Sometimes you can tell who the new guy is but that doesn't mean he is fair game and a pop-up target.

If however, you are an 'average' person trying to build the "perfect" engine with parts from Autozone's member's awards points you are on the wrong track - about that MAKG is right. Real engine development takes engineering and cubic dollars. I don't think that is what anyone is trying to do. It would be good for all of us to hear from someone who could talk intelligently about having modified, built and then drove or raced a particular "type" of 4.0 & engine control system, etc.

Completely understandable. if i offened anyone i apologize.
I think bird was fustrated because he had already said somthing about the maf in one of the earlier post.

 

[Doug904]

The heads will work from year to year, they'll work on early models with the stock timing but you'll be using premium no matter what you do. I wouldn't recommend getting it tuned to run lower grade fuel because that will negate your gains from the heads.

I run a early model bottom end, with 98TM heads Stage 3 ported (thanks Walt), 422 Comp cam, and all the common bolt ons. My engine makes 197 rwhp n/a and 284 rwhp on nitrous. I still have cast pistons and abuse the heck out of it at the drag strip.

Stay away from Morona, like before noted. His stuff is over priced and Non-tested.

Later Doug.

P.s. I forgot to renew my login when they changed servers or I'd been on sooner, I think that was like 4 yrs ago?