how hot should the head be?

[Terry Keeley]

but because of all the variables you need to be able to tune on the fly at the races and fully understand how all the variables affect each other

Very true!

Was out testing the SAW boat the other day, dropped the strut 0.030" to tighten the boat up a bit, everything else the same except now it wouldn't pipe.

Thought about it a sec, richened the needle up a few clicks and made another 110++ run. The extra load on the motor made it lean... B)

 

[John Finch]

but because of all the variables you need to be able to tune on the fly at the races and fully understand how all the variables affect each other

Very true!

Was out testing the SAW boat the other day, dropped the strut 0.030" to tighten the boat up a bit, everything else the same except now it wouldn't pipe.

Thought about it a sec, richened the needle up a few clicks and made another 110++ run. The extra load on the motor made it lean... B)

Good example Terry! It doesn't take much does it. I know you are chasing my 67 record and I know you can break it. You just need the right air density, glass water, and about ten variables to be right on the money. Oh, and the stars have to align perfectly! Like you say................not as easy as it looks. It took me 10 years of trying for the stars to align just right. Glad we got it on video. Another example.............the year before we broke the record we were running 80 percent nitro and had to squirt alcohol into the carb as we walked the engine to the water because the engine was so cold we couldn't get enough heat into it to get it to burn the fuel. Once the boat hit the water the load was there and the engine got some heat and took off. We had cardboard wrapped around the head, duct tape on the tuned pipe, and no water cooling at all. Was a chilly day! Got 113 mph out of it but the boat was too short and couldn't keep the prop deep enough into the water to get the full pitch.

When we set the record I used low nitro and a BOX STOCK CMB green head engine but a longer boat. Build the longer boat now that you have the dimensions. I would like to see you be the one to break the record. Good example of changing things on the fly for the conditions. AYE!

 

[Tim Kish]

I agree John , can't think of anyone more deserving to set that record than Terry

.

Tim

 

[Terry Keeley]

Build the longer boat now that you have the dimensions. I would like to see you be the one to break the record. Good example of changing things on the fly for the conditions. AYE!

Thanks John, you and Kentley are true gentlemen in every sense! Imagine, when I realized my boat was too short I asked these guys how long theirs was, said they "couldn't remember" but would let me know. Ya right I figured.

Next day Kentley brings the template from the record boat to the pond and hands it to me, I couldn't believe it! There are no secrets with these guys, it like lets see how fast "we" can go!

BTW, been running mostly on 70% but have some different 80% mixes to test, will let you know the results...

Oh, and my new boat will be out next year...

 

[moparbarn]

that's why i love racing down here in d-12 with these guys, terry. no secrets, will come look at your boat & tell you what they think you should do. i asked kentley about his drive dog to transom distance on his first jae. he said i don't know, but it's on my table - go measure it. and it's not just john & k.p, many more with years of racing & designing boats here are just like that, too!

 

[hugh hargett]

Hope you fellas are continuing to follow this discussion on jims boat dock . Jims there and continuing his discussion. Really good info there from others as well.

 

[hugh hargett]

"too bad" Only to those that choose not to get the info coz of the forum its on. Good luck Greg. The discussion goes on there for anyone thats interested .

Later,

Hugh

 

[Timbo Whalen]

Most of the heat is absorbed by the nitro. Nitro must absorb much more heat than gas or methanol to reach ignition temperature. When it final does have enough heat in it the nitro will burn and all of that heat energy is released as cylinder pressure. Therefore Nitro itself is the best "radiator" your engine could have. That's why we go faster when we restrict the water and open the fuel valve.

Lose the water pick up and Dump in the Nitro! Yeah Baby! HORSEPOWER!

DING! DING! DING!..... WE HAVE OURSELVES A WINNER!

Great job, Andy!.... simple, and accurate!..... nitromethane loves heat.

"When it final does have enough heat in it the nitro will burn and all

of that heat energy is released as cylinder pressure."- Ah-HAH!..... The

Transformation of Energy!... The First Law of Thermodynamics is the process

of changing energy from one form to another. Energy is a quantity that

provides the capacity to perform work, or provide heat. In addition to being

converted, according to the Law of Conservation of Energy (1st Law), energy

is transferable to a different location, or object, but it cannot be created or

destroyed within a closed system. Ol' Rudolf Clausius had it all figured out.

The Second Law of Thermodynamics states that the entropy of any isolated

system always increases. Isolated systems spontaneously evolve towards

thermal equilibrium- the state of maximum entropy of the system.

The more energy that is lost by a system to its surroundings, the less

ordered and more random the system is. The measure of randomness, or

disorder, within a system is called entropy. High entropy means high disorder

and low energy. Essentially, entropy is thermodynamic property that is the

measure of a system’s thermal energy, per unit temperature, that is- WATCH THIS!-

UNAVAILABLE FOR DOING USEFUL WORK.

Gases have higher entropy than liquids, and liquids have higher entropy than solids-



With regard to squish bands, head clearances, CR's.... tighter clearances are NOT

the best options for producing, or regulating, power in a nitro engine, especially

considering higher nitro percentages. Without going into non-intrinsic details,

we should be optimizing our engine's dynamics where they live- at the lake.

Manage the thermodynamic elements based on the dynamics.... pouring more water

on the fire is counterintuitive...... POUR MORE NITRO ON IT!, and reduce the static

cylinder pressure (ie-reduce mechanical compression ratio), adjust load through prop

and control combustion temperature with plug heat ranges.

You guys would freak out if you knew the temperature at the plug/button interface

during a WOT loaded run with my D Hydro at the pond. '3 second rule' is blown right

out of the water- we run ~300°F. with a large bore fuel system, very minimal coolant.

tim

 

[David Ashcroft]

If only our current fiat money had the instrinsic backing of gold and silver.

Yes I conditioned my cmb67 ,I cut on the intake ,,raised the exhaust timing a tad with a 0.008" shim Sleeve ,finger port on the sleeve ,I going to test the engine with a .0.014" clearance ,may need to lower squish to 0.012"for torque in the new mono build.

 

[David Ashcroft]

DING! DING! DING!..... WE HAVE OURSELVES A WINNER!

Great job, Andy!.... simple, and accurate!..... nitromethane loves heat.

"When it final does have enough heat in it the nitro will burn and all

of that heat energy is released as cylinder pressure."- Ah-HAH!..... The

Transformation of Energy!... The First Law of Thermodynamics is the process

of changing energy from one form to another. Energy is a quantity that

provides the capacity to perform work, or provide heat. In addition to being

converted, according to the Law of Conservation of Energy (1st Law), energy

is transferable to a different location, or object, but it cannot be created or

destroyed within a closed system. Ol' Rudolf Clausius had it all figured out.

The Second Law of Thermodynamics states that the entropy of any isolated

system always increases. Isolated systems spontaneously evolve towards

thermal equilibrium- the state of maximum entropy of the system.

The more energy that is lost by a system to its surroundings, the less

ordered and more random the system is. The measure of randomness, or

disorder, within a system is called entropy. High entropy means high disorder

and low energy. Essentially, entropy is thermodynamic property that is the

measure of a system’s thermal energy, per unit temperature, that is- WATCH THIS!-

UNAVAILABLE FOR DOING USEFUL WORK.

Gases have higher entropy than liquids, and liquids have higher entropy than solids-

View attachment 289488

With regard to squish bands, head clearances, CR's.... tighter clearances are NOT

the best options for producing, or regulating, power in a nitro engine, especially

considering higher nitro percentages. Without going into non-intrinsic details,

we should be optimizing our engine's dynamics where they live- at the lake.

Manage the thermodynamic elements based on the dynamics.... pouring more water

on the fire is counterintuitive...... POUR MORE NITRO ON IT!, and reduce the static

cylinder pressure (ie-reduce mechanical compression ratio), adjust load through prop

and control combustion temperature with plug heat ranges.

You guys would freak out if you knew the temperature at the plug/button interface

during a WOT loaded run with my D Hydro at the pond. '3 second rule' is blown right

out of the water- we run ~300°F. with a large bore fuel system, very minimal coolant.

tim

Head temp is regulated via fuel richness or water supply.
A good head temp is around 180 to 200 and can be controlled via pinching

 

[Timbo Whalen]

Head temp is regulated via fuel richness or water supply.
A good head temp is around 180 to 200 and can be controlled via pinching

Tell ya what. I run 60% nitro and run a lot hotter than 200°F.

And I barely run any water through them at all.... and I don't run these

tight squish clearances that some run.... and I use a bit hotter plug most

of the time. That's basically what Andy was talking about, we just explained

in terms of Clausius' Thermodynamic principles.

 

[David Ashcroft]

Tell ya what. I run 60% nitro and run a lot hotter than 200°F.

And I barely run any water through them at all.... and I don't run these

tight squish clearances that some run.... and I use a bit hotter plug most

of the time. That's basically what Andy was talking about, we just explained

in terms of Clausius' Thermodynamic principles.

Yes agreed the .12 and .21 engines are great at 200+

 

[Zimmerman]

Hey Terry!
Speaking of 80% nitro ... When the original crapshooter guys were after records they used 78% nitro, 12% castor and 10% propylene oxide. Charlie Sweet called it running "out out of the bottle"!