Cooling system pressure?

[siberianhusky]

How much pressure do you think these things are under?
Tested a cooling system with a mouthfull of water through the intake line, plugging the exit - no leaks.
Run the boat and end up with enough water in the hull to make me nervous.
Tried a bunch of things thinking it was coming up the stuffing tube, no solution.
Tested the cooling system again under higher pressure using Tony's patented pressure tester (hose and sink adapter)and the cooling can leaks like a sieve!
Easy fix but I was surprised at how much pressure it took for the leaks to show up.
Was really perplexed on this one, was about convinced it was coming up the stuffing tube but there was no oil in the hull, even tried straight grease to plug the tube. LOL even tapered a drive dog to eliminate the flat face thinking this may be causing the problem.
Not my area of math and physics classes were many,many years ago. How much pressure do you think we have going on in these things?
At least I know my system has good flow! Must if it can generate the amount of pressure it took for the leaks to show up!
Plain old rudder pickup, completely stock, no opening of the intake hole at all.

[martin]

Dont know how much pressure it takes but i know water lines can be blown off if not secured with clamps or zip ties, you cant seem to do this by blowing down the lines though so theirs much more pressure than you can blow.

[paultbg]

And what is Tony' s test method?
Share with us, please...

[runzwithsizorz]

If your can was out of round, and/or the O ring(s) were damaged, I would think that just the oral test would have shown something. I saw one person
here add a bead of silicone around the can. Maybe add a Y fitting close to the cans exit, and run two hose's out, that way you could be assured that
the amount of water going out was same, or better than the amount coming in, {volume}. You would think that running the water, first through an ESC
especially one with a dual plate, would slow the pressure, {velocity}, down somewhat.

Other then that,

[runzwithsizorz]

Dont know how much pressure it takes but i know water lines can be blown off if not secured with clamps or zip ties, you cant seem to do this by blowing down the lines though so theirs much .more pressure than you can blow

Have you seen my Blue Man imitation?

[siberianhusky]

An adapter that screws to your faucet stepped down with plumbing parts so you can attach a length of hose to adapt to the cooling system.
It really surprised me that it passed the first test with the exits plugged, yet still develops enough pressure on the water with the exits open to leak.
Motor and esc are cooled separately with a Y and dual exits!
About a 40 mph boat at this point, been dealing with the water problem and haven't really done too much set up work.
Once I found the leak no problems fixing it, just very surprised at how much pressure it needed to leak.
It was driving me nuts because it passed the first leak test and nothing I did made the slightest difference, always had about the same amount of water after 2 quick test laps.
I don't think we'd have as much fun if everything was easy.

[srislash]

I would like to know the pressure as well.Perhaps my uncle has something to test this as he is a plumber.I'll run it by him.

[ozzie-crawl]

I like to zip tie any lines in side the hull but leave the out side un zipped as a kind of weak link. Better than a hull full of water

[Remmie81]

I lately had to put on the water jacket of my Leopard engine several times and I justed wanted to make sure the o-rings were still ok.
As Ive heard in the past that with big pickups and high speeds the pressure could go up to 4 bar, I wanted to test the water jacket for leakage to prevent my boat from getting full of water.

I took an aircompressor and connected my waterlines (4mm inside diameter) to the waterjacket.
On the other side of the waterjacket again waterline with a very long bolt in it to make it block the air.

I didnt dare to go over 2 bar as the waterlines were growing and could even feel pressure in the waterjacket.
The waterjacket was still ok, no leakage, and the water lines didnt pop off.

So from my experience I would say that if the waterlines are popping off, it would be more then 2bar pressure.
Maybe I could test it later this week to see at what pressure a waterline pops off.....

[Chilli]

For those that don't know 2 bar is almost 30 PSI

[Jeff Wohlt]

Or even easier is do a vacuum test on it. You can find those suckers cheap.

[m4a1usr]

This is actually a pretty good question to ask. Dont even bother with a PSI gauge (if thats what you have or were planning on using). While in static measurment, and attached to your home water pressure (up to 45-55psig) you dont need to bother going over 3 to 5 psig. The true pressure your system will see is going to end up being in inches of water column. 1 PSIG = 27.7 inches of water column. The reason is obvious. One end is always open. Pressure cannot build beyond a minor amount. And pressure will be determined by line restrictions like tubing diameter, elbows or changes in flow direction. Water takes the path of least resistance. So if your cooling jacket has both nipples located on top and in line with each other chances are more water than you think never makes it down to the bottom of your motor to be of much use.

Its one reason I place little faith in water cooling jackets on motors as being very effective. Its better to do the calculations and size your motor and load correctly then relying on secondary heat removal methods. But that tends to fall on deaf ears. Not here to lecture either. Just my way of building boats.

John

[properchopper]

Here's my sink-attachment goodie :

DSC03224.JPG

One thing that keeps popping up in my mind is that sink-testing doesn't take into account any possible heat-expansion factors occuring during actual runs on the lake. I'm probably over-thinking this but it's still a question I wonder about.

I do a lot of motor swapping and when a cooling can-to-motor seal is questionable, I'll silicone the can to the motor or use this stuff :

DSC03225.JPG

I'm with John on the effectiveness of watercooling as a panacea for keeping temps in the safety zone. The cooling water doesn't get in close enough proximity to the heat-challanged items to do a whole lot of preventative good. Balancing setups is the way to control temps.

Then again, a cooling fan accelerating airflow over potential hotspots has done wonders


DSC03222.JPG

[1945dave]

I love it. You asked about pressure values and no one gave you any.

There are a couple of reasons these numbers are not always exact but for your purposes this should be close enough.

5.6 PSI = 20 MPH; 12.6 PSI = 30 MPH; 22.4 PSI = 40 MPH; and 35 PSI = 50 MPH.

Please note these pressure and speed changes are progressive not linear. That is why the old pitot tube speedometers for boats showed a large range of movement for lower speeds making it easy to distinqish 10 mph and 12 mph, and once you got to something around 50 mph the range of rotation becomes very tight and accuracy much harder to read.

Using the typical city water pressure available in most American cities, faucet pressure is approx. 60 psig.

For your diagnostic purposes I would make a nice controlled run slow enough to produce a good steady stream of water out the exit tube. This would provide good cooling and lower pressures on your system. If you discover you have little leakage then increase your speeds. In my younger days I seem to remember being able to blow about 8 psi into a pressure gage, not very much. On the other hand there is no reason to test for pressures above speed pressures indicated here for your boat.

Dave

[siberianhusky]

Not a problem at all really, was solved as soon as I figured out what was up, just the pressure that must be developed is higher than I would have thought in a open system considering it didn't leak with a lower pressure closed system test.
All very interesting though.
I agree also with Tony and Jeff, a proper setup shouldn't have to rely on watercooling to live. Last season I did an accidental full length run with no cooling going to a PB 1800kv motor and esc, they were hot, not going to lie about that but they are still both working fine.
The internal temp of the motor even with cooling is HOT, a couple times I've left the logger running after a run with the temp sensor on the motor, the temps sky rocket once the run is over, the heat soak of the rotor and magnets must be unreal, temps went from the 90's to over 125 in less than a minute.
Now I try to open up the motor mount if the motor has ventilation holes some airflow is better than none.