dyno dissapointment 3.4 iron head

[geoffinbc]

What was the operating temperature of the motor with these numbers? You need to get that thing to 200*F MINIMUM. Don't try and dyno it at 160~180 thats way too low. An engine will make more power the hotter it gets up to about 220* But running at 220* leaves too little of a safety margin so always keep it between 200* and 210* Get rid of the 160* stat and run a 195*. The V springs you chose are a little stiff for the application but still acceptable and wont bother the power output. The other thing I would change is the intake top. It is easy do do an worth a look. If you want swap the heads around and see what happens. You should be able to get over 200HP. Guys with 3.4L's and TBI induction are getting 180 at the wheels of an S-10.

Did the operator bother to get the engine up to full temp? Richening the mixture and adding timing is not the way to add power all the time. Did he try and lean it out and take some timing out?

My other curiosity is how you could have killed 3 motors in 1 year?

[ezrollin]

"howdy, lol. just drove through your state... not going to lie, i was bored" Kind of rude don't you think ? How can you spend that kind of money and make less hp than a stock 3.4 ? There's one thing I've learned over the years,to make sure a componet produces before spending my money. There's lots of crap out there to take your hard earned cash!

[treeZ24]

you didnt state your static compression ratio so it cant be that much more then stock (9.6~). with the camshaft you have and the bigger rockers i would think your engine would really benifit from a bump. run through the dynamic compression ratio calcs and see what you can come up with. right now i guarantee you its going to be too low.

[merlot566jka]

treez24 compression is 9.95:1. 3.4 bored .020 over, .010 off the heads and block was zero decked

ezrollin, that wasnt meant to be rude. sorry bout that, im a playfull person, some times i play a lil rough...its the military background. again i apologize if i offended anyone

better than you, the temp of the engine never gets above 185. the fan kicks on (controlled by the ecm) at 195 and off at 185
the engine was at the max temp it will reach when he tuned it. the car was actually running a tad bit lean, you can see it on the dyno graph (sort of)
3 motors in a year..yeah uhhh...the 2.8 it had when i got it had 5 lifters fail (the po had some over heating issues and replaced the entire cooling system, when i got the car i drove it for a bit and started to hear some lifter noises, pulled it apart saw the coked oil and decided to go 3.4) and the 3.4 i got was from a yard, guy told me it had like 60K on it...had a bearing go 20 mins after install, got another engine from the same guy for free, bearing failure 2000 miles later, and thats where i am now. mew short block from city motor supply

and im in a self conflict here...port and polish the iron heads and go turbo, or try the 3500 heads swap. the money ive sank into these iron heads and components is leaning me towards turbo. im not looking for a 500hp car, but 300hp sounds about goood to me. the iron head motors have been seen at the 300 hp and more range several times. wth the 24lb injectors and stainless valves, ive got a couple turbo friendly items...3500 heads lands me north of 11:1 CR, not so turbo friendly.

[bszopi]

I'm not offended about you saying Arkansas is boring. I only live and work here. I lived in OK for 6 years, and my parents still live there.

Scroll up and read Shaun's post (we have to approve his posts to keep him in check, lol). I will have to agree with him that stock heads are going to be a restriction, and even heads ported too much should still out perform the stock heads.

And as far as the cooling system goes, I agree with Geoff (bty). Get rid of the 160º stat and reprogram the ECM to change the fan turn on times.

[Joseph Upson]

treez24 compression is 9.95:1. 3.4 bored .020 over, .010 off the heads and block was zero decked

ezrollin, that wasnt meant to be rude. sorry bout that, im a playfull person, some times i play a lil rough...its the military background. again i apologize if i offended anyone

better than you, the temp of the engine never gets above 185. the fan kicks on (controlled by the ecm) at 195 and off at 185
the engine was at the max temp it will reach when he tuned it. the car was actually running a tad bit lean, you can see it on the dyno graph (sort of)
3 motors in a year..yeah uhhh...the 2.8 it had when i got it had 5 lifters fail (the po had some over heating issues and replaced the entire cooling system, when i got the car i drove it for a bit and started to hear some lifter noises, pulled it apart saw the coked oil and decided to go 3.4) and the 3.4 i got was from a yard, guy told me it had like 60K on it...had a bearing go 20 mins after install, got another engine from the same guy for free, bearing failure 2000 miles later, and thats where i am now. mew short block from city motor supply

and im in a self conflict here...port and polish the iron heads and go turbo, or try the 3500 heads swap. the money ive sank into these iron heads and components is leaning me towards turbo. im not looking for a 500hp car, but 300hp sounds about goood to me. the iron head motors have been seen at the 300 hp and more range several times. wth the 24lb injectors and stainless valves, ive got a couple turbo friendly items...3500 heads lands me north of 11:1 CR, not so turbo friendly.

I believe your compression ratio will be much higher than you think with the 3500 heads on the flat tops already in the engine in which case on pump gas at 200 degree temps it might not be driveable without detonation. You would only be a notch off from the 3500 displacement and even with the soup bowl cut out of the top of its pistons compression is still 9.8:1.

I believe the bearing issue is a secret with the 3.4, I purchased my first as a very clean core that appeared to be in very good shape except for a spun main bearing.

You should shop around, for a complete engine, it sounds hopeless but the 3500 is not as expensive as it used to be, you should be able to find one in the 4-500 range. Some hard head would give you at least $400 for your intake, and probably near $200 for the heads as long as you have the paperwork. Even better, you can put the stock springs back on them and sell the cam with the performance springs for a good return and that short block should net you at least $300. It will go quicker in parts.

The reason I push the 3500 over the 3400 is because of the number 6 piston problem you could run into in a used 3400 unless it is newer than say 2003 or whenever they fixed it.

[Joseph Upson]

What was the operating temperature of the motor with these numbers? You need to get that thing to 200*F MINIMUM. Don't try and dyno it at 160~180 thats way too low. An engine will make more power the hotter it gets up to about 220* But running at 220* leaves too little of a safety margin so always keep it between 200* and 210* Get rid of the 160* stat and run a 195*.

I would like to see proof of this, I would readily accept the statement for a stock tune where the programming is more specific about certain functions based on engine temp like closed loop for instance, but in all the engine swaps I have done I have never felt performance increase as temps approached 200 degrees, and seat of the pants measurements were that much different that I have always tried to avoid temps approaching 200 degrees. That's more an emissions goal than performance I believe.

If the lower temp can be tuned for, dynamically it should produce more power because as the engine temp goes up the air density is going down, the 2.8 L has a baffle on the lower intake manifold to help fight against that. 160 is probably to low but, I can't see a 200-210 deg engine making more power than it would at 180. If proven wrong it will certainly help break my habit of drilling holes in the thermostat base to allow some coolant bypassing which I also do as a safety measure against a failed thermostat.

This is not to spark debate, it just suggests the opposite of what I have experienced; as temp goes up, power goes down.

[sprucegagt]

NASCAR engines normally run inbetween 210 - 220 *F. This is done on purpose because dyno testing has proven a gain. Why? Well the hotter the engine, the more efficient the burn you get in the power stroke. The trick is not to get it to hot to cause detonation.

[SappySE107]

yup, efficiency = power. Use a 195 stat and drill a small hole anyway. That is what I do because bleeding the system is important and that hole makes life easier. Its so small that its not going to change the operating temperature.

[Joseph Upson]

NASCAR engines normally run inbetween 210 - 220 *F. This is done on purpose because dyno testing has proven a gain. Why? Well the hotter the engine, the more efficient the burn you get in the power stroke. The trick is not to get it to hot to cause detonation.

It can't be the same for a daily driver. Not so much the theory but the conditions which in a NASCAR engine would most likely be in a performance range us street rodders are not likely to see much of let alone approach with our motors. I won't even go into the technology and precision involved with those motors to suggest there is very little to compare.

In a sense it's an apples to oranges comparison given the operating range the NASCAR engines are built to run in, are they using regular pump gas? There are to many parameters you have to overlook in comparing our motors to a NASCAR dyno finding. Higher octane fuel requires more energy to burn, that's why it doesn't do well in a low compression motor, bump the compression up, that adds more heat to the compressed mixture and high octane gas is suddenly practical again.

210-220 for a NASCAR motor may be great, but I will not believe it for our slugs until it's tested on a street motor.

I have to many V8 experiences alone to go with the NASCAR conclusion. Seat of the pants in the same car over a temp range does not lie, I would feel the power loss before looking down and confirming a higher temp.

Who knows maybe it's just the cars I've driven.

[discostu]

Edit: oops

[sprucegagt]

You would be surprised how much stuff from racing is carried over to street vehicles. Examples: knife edging and undercutting counterweights (see 3500 crank), small or no grill openings for radiator (name your late model J body), coatings for engine components (see revised 3400 pistons) and thats just stuff of the top of my head.

As for differences, well they can't really be all that different. Both are V shaped, pushrod, gas powered, internal combustion piston engines. What improves efficiency for one will do the same for the other. If you were talking about a diesel, rotary or turbine vs. a gas powered IC engine, then you may have a point.

High octane gas is also less efficient then regular 87 octane gas. NASCAR engines use such a high octane because of the high combustion chamber pressures they generate (compression is only a part of it). It is actually a draw back that they have to use high octane because low octane generates more heat while having a lower flash point. Now if you remember your physics class you'll remember that heat = energy. Thus the more heat you generate the more energy is available.

You felt a difference with the higher engine temp because of the increase in intake air temperature. Old V8 engines suffer from the same problem 60*V6 engines have, to much metal surrounding the intake runners. Why do you think edelbrock came out with there "Air Gap" series for those old V8 engines? It's the same thing NASCAR engines moved to, from using traditional intake manifolds. It makes a difference because the intake is not acting so much as a heat sink due to less metal and more air flow around the intake runners. That's what engine builders always strive for: a cold intake with hot heads and block. It creates the most efficiency thus providing more power with less waste.

[rsisbetter]

whats the #6 piston problem?

[IsaacHayes]

I'm wondering myself if the 180F stat I put in is killing my power. I drilled 2 holes in it and I didn't even have to bleed the system. (no air came out). It bled itself! Normally you have to wait until the stat opens which takes a long time of idling with the hood down.

Anyway, the temp gauge is under 1/4 now (normally right at 1/4). And the motor just seems to not have the power when stock. It does run worse and rough when it gets hot before the fan kicks on, but this is sitting in traffic and taking off which isn't much of an issue when you are moving.

I think I will throw the 195F back in there and see where I'm at.

Should I drill holes? If so, how many? Will one be enough to burp itself or do I need to put one on the bottom too to prevent vacuum?

[Joseph Upson]

You would be surprised how much stuff from racing is carried over to street vehicles. Examples: knife edging and undercutting counterweights (see 3500 crank), small or no grill openings for radiator (name your late model J body), coatings for engine components (see revised 3400 pistons) and thats just stuff of the top of my head.

As for differences, well they can't really be all that different. Both are V shaped, pushrod, gas powered, internal combustion piston engines. What improves efficiency for one will do the same for the other. If you were talking about a diesel, rotary or turbine vs. a gas powered IC engine, then you may have a point.

High octane gas is also less efficient then regular 87 octane gas. NASCAR engines use such a high octane because of the high combustion chamber pressures they generate (compression is only a part of it). It is actually a draw back that they have to use high octane because low octane generates more heat while having a lower flash point. Now if you remember your physics class you'll remember that heat = energy. Thus the more heat you generate the more energy is available.

You felt a difference with the higher engine temp because of the increase in intake air temperature. Old V8 engines suffer from the same problem 60*V6 engines have, to much metal surrounding the intake runners. Why do you think edelbrock came out with there "Air Gap" series for those old V8 engines? It's the same thing NASCAR engines moved to, from using traditional intake manifolds. It makes a difference because the intake is not acting so much as a heat sink due to less metal and more air flow around the intake runners. That's what engine builders always strive for: a cold intake with hot heads and block. It creates the most efficiency thus providing more power with less waste.

I see your point however the examples you gave are not good comparisons, special coatings, and knife edging a crank are more like constants, their properties don't change relative to the surroundings, a slippery surface remains slippery and the aerodynamic slicing qualities of a crank are not affected by the engine application. Heat = energy is not the complete equation otherwise it would suggest the hotter the engine the more power it produced. In this case heat is a by product of combustion a portion of which is wasted energy a large part of which can be recaptured by a turbo for example. Running the engine leaner will produce more heat but it will not necessarily increase power output.

You did mention the air gap intake manifold and its benefits which I also stated has an effect along with other mods our engines don't have to insure the same results at higher temps. Being familiar with physics you know the rate of heat dissipation is directly affected by the metal transfering it, in which case an aluminum block vs. an iron block will register different temps at the same water temp. Over port iron heads and your engine will run hotter. Another issue is the fuel, NASCAR engines need more compression to burn their high octane fuel properly and visa-versa, the temp they run is a function of the fuel they are required to run as was stated, for a more efficient burn. Who knows what else they did to get more power at those temps permitted by the fuel composition; leaner mixture, more timing, you just don't know.

Premium fuel being less efficient is an incorrect statement, it's less efficient in engines that do not have the necessary compression to burn it efficiently. Otherwise we can save more money and make more power on cheaper lower octane fuel like 80 octane vs. 87 and 7:1 compression for example.

If you can go back and catch last week or the week before lasts horsepower TV, you can see the Dyno difference they demonstrated on television with a late model LS series chevy engine. They did a run with 87 octane and a run with premium octane fuel. Premium in the same engine made more power and better fuel economy according the computer generated results, which measured the fuel consumption as part of the dyno pull because a vendor provided a fuel treatment product that goes in the fuel line and treats the fuel resulting in higher mileage. They did that run last and it proved that the product actually did what the vendor said it would.