Why our O rings fail:
#1
Blow up or win
Thread Starter
Why our O rings fail:
This has been bugging me for a while, and I've heard
all the traditional ideas, they just don't adequately describe what is going on. I think I've finally figured out the problem:
The phenomenon is known as electrochemical degradation, or ECD.
It occurs because the rubber O ring, liquid coolant (ethylene glycol antifreeze and water), and the engine internals/radiator fittings form a galvanic cell or "battery." This chemical reaction causes microcracks in the O ring, allowing the coolant to attack and weaken the rubber.
With the rotary's abundant aluminum and iron internal plates in close proximity to each other we literally have a more powerful "battery", hence the premature failure.
How to prevent O ring failure from happening again after you get a rebuild? (which HAS been happening in epidemic proportions) easy: eliminate the aqueous based coolant - and while I am not a fan of Evans because of it's extravagant price - (and I really don't think it works any better to cool than a well maintained glycol based OEM system) - it just could be the best investment available to keep that rebuild running forever.
That's my thesis and I'm sticking to it.
all the traditional ideas, they just don't adequately describe what is going on. I think I've finally figured out the problem:
The phenomenon is known as electrochemical degradation, or ECD.
It occurs because the rubber O ring, liquid coolant (ethylene glycol antifreeze and water), and the engine internals/radiator fittings form a galvanic cell or "battery." This chemical reaction causes microcracks in the O ring, allowing the coolant to attack and weaken the rubber.
With the rotary's abundant aluminum and iron internal plates in close proximity to each other we literally have a more powerful "battery", hence the premature failure.
How to prevent O ring failure from happening again after you get a rebuild? (which HAS been happening in epidemic proportions) easy: eliminate the aqueous based coolant - and while I am not a fan of Evans because of it's extravagant price - (and I really don't think it works any better to cool than a well maintained glycol based OEM system) - it just could be the best investment available to keep that rebuild running forever.
That's my thesis and I'm sticking to it.
#2
Speed Mach Go Go Go
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Racing Beat light weight aluminum side housing will get rid of most of the iron (only double the cost).
If that thesis gets you in to UCLA hook me up with some chearleaders!
If that thesis gets you in to UCLA hook me up with some chearleaders!
Last edited by GoRacer; 06-20-03 at 07:00 PM.
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#8
Speed Mach Go Go Go
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^ distiled water? Do you think "ANY" race shop or dealer will go out of their way to buy distiled water or will they use free tap water? Even if you provide the water they may forget and still use tap and not tell you.
#9
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Originally posted by JONSKI
Actually, Mr. Wankel (the forum member) tells me that o-rings fail because of some right-wing conspiracy to protect the interests of piston engines.
Actually, Mr. Wankel (the forum member) tells me that o-rings fail because of some right-wing conspiracy to protect the interests of piston engines.
#11
5yr member, joined 2001
Originally posted by Nathan Kwok
Hmmm interesting. However, distilled water isn't electrically conductive, would ECD still occur in that case?
Hmmm interesting. However, distilled water isn't electrically conductive, would ECD still occur in that case?
#12
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Originally posted by Kento
Evans coolant isn't aqueous-based? What is its primary composition then? (not being a smart-***, just seeking info)
Evans coolant isn't aqueous-based? What is its primary composition then? (not being a smart-***, just seeking info)
Search for their website to read more about it.
#13
2/4 wheel cornering fiend
Originally posted by Nathan Kwok
Hmmm interesting. However, distilled water isn't electrically conductive, would ECD still occur in that case?
Hmmm interesting. However, distilled water isn't electrically conductive, would ECD still occur in that case?
#14
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Running 100% distilled through the winter, even when the car is stored in a garage, will kill your O-rings. Don't ask how I know this :p
Also, if you run pure distiled you will have corosion problems. On a positive note it definately lowered my temps over the 60/40 mixture I used to have.
Semi related question: Isn't there a way to use a metal rather than rubber seal?-maybe press a tube into the coolant passage section that connects the housings.
Also, if you run pure distiled you will have corosion problems. On a positive note it definately lowered my temps over the 60/40 mixture I used to have.
Semi related question: Isn't there a way to use a metal rather than rubber seal?-maybe press a tube into the coolant passage section that connects the housings.
#17
5yr member, joined 2001
Originally posted by CCarlisi
Semi related question: Isn't there a way to use a metal rather than rubber seal?-maybe press a tube into the coolant passage section that connects the housings.
Semi related question: Isn't there a way to use a metal rather than rubber seal?-maybe press a tube into the coolant passage section that connects the housings.
#18
Rotary Freak
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Ron AKA Mr. Minister of Optimistic Information may have something here.
It's a known fact that one can determine when to change coolant by measuring the voltage difference between the coolant and the block. If it's more than 1.0 V, change the coolant. Don't believe me? Take a sensitive digital voltmeter, stick the positive probe into the coolant fill cap and the other probe on the block, you'll see a voltage difference.
Now as to distilled water: Yes. water is a great solvent meaning that it loves to dissolve all other stuff around it. Distilled water has almost no minerals in it so it tries to dissolve the block. That's why I run coolant mixed with tap water: plenty of minerals in it.
But hey, this same action occurs in pistons also but I don't see alot of head gasket problems in 15 years old Toyota (iron block/ aluminum head) or Mazda pistons (iron/aluminum). Hell, even NA rotaries last 150K or more.
So I think your premise is part of it: the heat cycling, the voltaic degradation, the make up of the o-ring itself. But like you said, there ain't no icoolant ring problems with rotary just like there is no Americans in Bagdad.
It's a known fact that one can determine when to change coolant by measuring the voltage difference between the coolant and the block. If it's more than 1.0 V, change the coolant. Don't believe me? Take a sensitive digital voltmeter, stick the positive probe into the coolant fill cap and the other probe on the block, you'll see a voltage difference.
Now as to distilled water: Yes. water is a great solvent meaning that it loves to dissolve all other stuff around it. Distilled water has almost no minerals in it so it tries to dissolve the block. That's why I run coolant mixed with tap water: plenty of minerals in it.
But hey, this same action occurs in pistons also but I don't see alot of head gasket problems in 15 years old Toyota (iron block/ aluminum head) or Mazda pistons (iron/aluminum). Hell, even NA rotaries last 150K or more.
So I think your premise is part of it: the heat cycling, the voltaic degradation, the make up of the o-ring itself. But like you said, there ain't no icoolant ring problems with rotary just like there is no Americans in Bagdad.
#19
Rotary Freak
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Originally posted by CCarlisi
Semi related question: Isn't there a way to use a metal rather than rubber seal?-maybe press a tube into the coolant passage section that connects the housings.
Semi related question: Isn't there a way to use a metal rather than rubber seal?-maybe press a tube into the coolant passage section that connects the housings.
When I first split open the old Subaru flat four I found that it doesn't have a head gasket b/w the block and the head as they are of the same material. B/c it's the same material, they expand at the same rate w/o requiring a gasket in between. Don't know about the new Subaru motors though.
#20
Rotary Enthusiast
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Originally posted by RonKMiller
That's my thesis and I'm sticking to it.
That's my thesis and I'm sticking to it.
Originally posted by CCarlisi
Semi related question: Isn't there a way to use a metal rather than rubber seal?-maybe press a tube into the coolant passage section that connects the housings.
Semi related question: Isn't there a way to use a metal rather than rubber seal?-maybe press a tube into the coolant passage section that connects the housings.
Originally posted by JONSKI
Actually, Mr. Wankel (the forum member) tells me that o-rings fail because of some right-wing conspiracy to protect the interests of piston engines.
Actually, Mr. Wankel (the forum member) tells me that o-rings fail because of some right-wing conspiracy to protect the interests of piston engines.
#21
Need more sleep
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Most aqueous solutions (water!) are corrosive to ferrous and aluminum alloys that build weak oxide layers. Even austenitic stainless steels are suceptible to aggressive cracking and under deposit pitting at coolant system temps.
Distilled water only helps prevent gross mineral fallout/deposit as compared to tap water. If your chosen coolant has a poor add pack and reacts with blowby gases or decomposes with time/temp it will suffer from mineral deposit too.
Evans, good choice for me so far.
Distilled water only helps prevent gross mineral fallout/deposit as compared to tap water. If your chosen coolant has a poor add pack and reacts with blowby gases or decomposes with time/temp it will suffer from mineral deposit too.
Evans, good choice for me so far.
#23
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Yes. But that requires the housing and the end plates to be of the same material. The o-ring allows for thermal expansion of different materials. And the o-rings are designed to move in its groove for sealing.
#24
Lives on the Forum
Originally posted by Silver bullett
What about silcone O rings? Do they make them and do they last longer?
What about silcone O rings? Do they make them and do they last longer?
#25
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Originally posted by twokrx7
Most aqueous solutions (water!) are corrosive to ferrous and aluminum alloys that build weak oxide layers. Even austenitic stainless steels are suceptible to aggressive cracking and under deposit pitting at coolant system temps.
Distilled water only helps prevent gross mineral fallout/deposit as compared to tap water. If your chosen coolant has a poor add pack and reacts with blowby gases or decomposes with time/temp it will suffer from mineral deposit too.
Evans, good choice for me so far.
Most aqueous solutions (water!) are corrosive to ferrous and aluminum alloys that build weak oxide layers. Even austenitic stainless steels are suceptible to aggressive cracking and under deposit pitting at coolant system temps.
Distilled water only helps prevent gross mineral fallout/deposit as compared to tap water. If your chosen coolant has a poor add pack and reacts with blowby gases or decomposes with time/temp it will suffer from mineral deposit too.
Evans, good choice for me so far.
Also, it is (Propylene Glycol) 100% water soluble, so don't listen to that nonsense about getting 100% of the water out of your system