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  #1  
Old 07-02-2007, 02:59 PM
raddy raddy is offline
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Default Checkvalve failure

Hi
I just found problem in my coolingmist system.....Few weeks ago I noticed drop in water level, car was not driven at this time, so water just dissapear from tank.....I start to checking all fittings, pump etc, but no signs of water leak.....Just note, I have 2 nozzle setup (before turbo, before TB) both nozzles have brass checkvalves (supplied by coolingmist) in their lines....I was really nervous about water missing, but just last thing that I checked was right one.....I disconnect inlet turbo hose and 1/2 litre of water comes out of it :shock: :?
Yes, checkvalve for pre turbo nozzle (located below in relation to tank) was stuck open......and water slowly siphoned through pump and nozzle into hose and turbo. Yes, turbo (compresor housing) was flooded with water.
I removed this checkvalve to confirm that it is stuck open. Put thin screwdriver in it and push few times against flap inside. It moves normally, no signs of something wrong with/in it. After this it closes perfectly again....Something must was inside, I really dont know. Sure, Im using only distilled water in system.
Put it back, all is normal again. I will add 3rd checkvalve right after pump to prevent this in future. And yes, turbocharger last it, it working fine (no blade damage, no axis movement), just some water comes to oil, but after long run without any WI it comes out through breather.

Did you ever meet with similar failure?
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Old 21-02-2007, 08:46 PM
JohnA JohnA is offline
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Default Re: Checkvalve failure

Yes, I had mine stuck shut.
No reason why, maybe there was interaction with methanol, who knows....

The system had been inactive for 2-3 months, as I took it from the previous car and had it stored to be used in the next one. Now I assume nothing, everything is treated as a potential failure point!
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  #3  
Old 08-05-2007, 12:23 PM
raddy raddy is offline
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Hi
Im back with serious problems with pistons, just to confirm that it wasnt caused by water/ethanol injection.
5000km ago I get damaged pistons. They was damaged in strange way, no damage at all at the top of the piston or top edge, but complete destroyed between the rings. Engine was rebuilded. Now I have same damage. It looks very strange for me. Garage told me that reason is too high compression/boost pressure caused melting piston. But this should leave clear signs on the top of the piston, isnt it?
Anyway, here are pictures:

top of the piston, no visible damage (4 dots are marks for No. of piston)
http://www.ukazto.com/?img=P101000x.jpg

side of the piston, damage
http://www.ukazto.com/?img=P1010004-wxy1.jpg

Edit: just note that top comp. ring is undamaged.

Thanks for your advice.
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Old 08-05-2007, 06:32 PM
keithmac keithmac is offline
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That`s very strange!, I suppose high compression could be a factor, definitely no signs of detonation. What piston is it (forged?). Is the conrod still true?.
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  #5  
Old 08-05-2007, 09:16 PM
raddy raddy is offline
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this should be explanation, page 36
http://www.cabletiemotorsport.com/Pistons.pdf


I must also note that damage at all pistons was only at exhaust side. The true is that I probably too much advanced ignition after WI installations. As I never hear detonations, with WI a feeled safe. But not all dets can be audible.....
It wasnt forgeds, just standart pistons.
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Old 08-05-2007, 09:47 PM
keithmac keithmac is offline
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What advance/boost were you running?. Cheers for the link some good reading there!.
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  #7  
Old 09-05-2007, 08:28 PM
raddy raddy is offline
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I was running with 1.3bar of boost. And timing should be 25deg, if using formula timing map value-16. Thats with 98octane fuel and water injection, pre and post turbo. Maybe WI can be explanation why I didnt heard typical knock sound....
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  #8  
Old 12-08-2007, 02:36 PM
Richard L Richard L is offline
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Wouldn't be possible to install a solenoid valve inline, they have much stronger springs and does not caase as much pressure drop at the checkvalve.

How old is your checkvalve?
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  #9  
Old 13-08-2007, 03:58 PM
raddy raddy is offline
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Hi Richard

In meantime I add 3rd checkvalve just after pump (before dividing water line to pre comp and pre TB), so in case of same failure of one checkvalve it will be secured by this 3rd one....Checkvalve which was stuck open was about 1 year old. But after this it never happens again, so Im using it again.
I know that solenoid can be more suitable, but I was preffering mechanical setup at this time, but you are right, maybe I will use solenoid then.

Just a question regarding to pressure drop at checkavalve: can you explain this more deeply please? It mean that if checkvalve have cracking pressure let say 30psi, and pump is 150psi that at nozzle I will have just 120psi pressure?
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  #10  
Old 13-10-2007, 09:35 AM
Richard L Richard L is offline
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Almost all progressive systems use a checkvalve between the pump output and nozzle for the reasons listed below:

Positive effects (well documented):
1. Retain some pressure in the line to compensate the next injection event. A 20psi loaded checkvalve will keep 20 psi of pressure in the line after injection.
2. Stop water being siphoned into the engine if the water jet is installed in the vacuum side of the manifold.
3. Prevent emptying the entire tank into the inlet tract if the tank location is higher than the jet (gravity fed) or the car is parked on an incline.
4. Stop some dribble after an injection event. Even when the power of the pump is switch off, the inertia of the rotating mass keeps the pump running for a second or so.

Negative effects (less well documented):
5. The presence of a checkvalve has a very significant impact of the dynamic range of a 150psi progressive pump speed system. A 20 psi checkvalve inline will instantly drop the 150 PPS system down to a 130psi span.

6. A normal nozzle requires ~30psi for produce a decent atomised spray. An inline 20psi checkvalve means the pump has to produce 50psi to produce a decent spray.

7. Let say the PPS system?s starting point is at 12psi boost, the system will now require 62psi to produce a decent spray. Some vendor will tell you a check valve will not impede flow once it is opened, true. But it will tax the pressure heavily where the PPS system relies heavily upon.

8. When the PPS system arrives at 24psi boost (end point) manifold pressure, the dynamic pressure is now further taxed. Before not too long later the dynamic range of a PPS system is now from 62psi to 126psi ? translate it to flow: 176cc/min to 326cc/min, a mere 84% percent increase.

9. I have taken some data from a reputable PPS system manufacturer, a 150-psi 60W Shurflo flow pump has the follow characteristics:

M2 nozzle with 1/8 ID hose 180psi
M3 nozzle with 1/8 ID hose 160psi
M5 nozzle with 1/8 ID hose 135psi
M14 nozzle with 1/8 ID hose 105psi

From the figures above, the pump is only capable of sustaining 135psi system pressure on a M5 nozzle. Despite claiming the pump is capable of flowing one 3-4 litre per minute, conveniently missing the pressure parameter. The above PPS system maker is the only one that published these figures in public ? thumbs up for them.

Summary:
Some PPS system makers are now offering an inline solenoid upgrade so that the dynamic range is improved by a good margin. Not sure why they didn?t include it in the kit at the beginning. Many PPS systems run their pumps up to 200-300psi - something I have questioned Shurflo, they said NO, NO and NO - no "ifs" or "buts". They are looking into a higher pressure pump but not yet done and will not be released until they are comfortable with it. I have a meeting with the Shurflo's director of engineering at our works two months ago during his UK visit - he confirmed the imaginary 200psi+ pump (8000 series).


Here is an illustration of the above in graphical form:

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