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Thread: Where is the Vernatherm valve on the Stroker 340

  1. #21
    Senior Member Pete D's Avatar
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    Default Re: Where is the Vernatherm valve on the Stroker 340

    When the gage reads 180 degrees, that just means that is the temp of the oil at the probe. One would have to study the oil system flow, but there are areas of the system where the oil will get hotter than what the gage reads, and areas where it is cooler than what you are seeing on the gage.

    How it was explained to me was that when you see 180 degrees (ideally something like 60 minutes every week or two) that means that somewhere in the system the oil is hot enough to evaporate an average accumulation of moisture in that given time period.


    Pete D.

  2. #22
    Senior Member turbopilot's Avatar
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    Default Re: Where is the Vernatherm valve on the Stroker 340

    Quote Originally Posted by Norm View Post
    Turbopilot, moisture evaporates at 112* F. Heat water in a pan on the stove and check the temp with an infra red temp gun and notice the moisture rising from the pan. It just does it faster at 212* F. Isn't that correct?
    Sure. The issue is to get moisture out of the oil faster than it is getting into the oil. Combustion adds water to the oil, evaporation or boiling gets it out. As I understand the process getting water in the oil over the boiling point moves all water out of the liquid phase into the vapor phase where it will vent overboard via the breather.

    Running the engine in a manner where the water in the liquid phase in the oil never gets to the boiling point can create a situation where the liquid water content of the oil continues to build as the water contribution of the oil continues to increase since water added by combustion exceeds water loss through evaporation. Evaporation of course is influenced by relative humidity where the plane is parked.

    Bottom line is that you want an aircraft engine that has oil with the lowest content of water in the oil possible to prevent corrosion when the aircraft is sitting idle. An aircraft flown frequently getting the oil above the boiling point of water will tend to keep the water content of the oil as low as possible.
    Bob Anderson, CC11-00316, N382RA

  3. #23
    Senior Member Centmont's Avatar
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    Default Re: Where is the Vernatherm valve on the Stroker 340

    Another consideration in the mix is altitude. Water reaches vapor stages at lower temps in reduced atmospheric pressure. In fact, boiling point is just over 190 F at 10K feet.

    And another thing for the mix.... sublimation. Water can evaporate at almost any temperature. If you hang frozen clothes on the line, they will dry out. This is just fun science and an interesting discussion. R
    Last edited by Centmont; 03-25-2011 at 07:28 PM.

  4. #24
    Member Norm's Avatar
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    Default Re: Where is the Vernatherm valve on the Stroker 340

    Quote Originally Posted by Pete D View Post
    When the gage reads 180 degrees, that just means that is the temp of the oil at the probe. One would have to study the oil system flow, but there are areas of the system where the oil will get hotter than what the gage reads, and areas where it is cooler than what you are seeing on the gage.

    How it was explained to me was that when you see 180 degrees (ideally something like 60 minutes every week or two) that means that somewhere in the system the oil is hot enough to evaporate an average accumulation of moisture in that given time period.
    Pete D.
    I agree, Pete, what u say has been the gold standard / rule of thumb that I've heard for 40 years of flying and I believe it to be a good recommendatition.

    What I said in my original post in this thread was, "Maybe 180* F is perhaps the *ideal* oil temp but I wouldn't be concerned with lower temps on a sustained flight." Sustained flights of longer duration would mean you could accept lower oil temps to give the moisture more time to evaporate out. That's what I was saying.

    Centmont, you bring up a good point about reduced boiling point at altitude ... something we often forget about.

    Turbopilot, good point about the combustion process creating some moisture. Early in this thread in May, 2010, you refer to 180* oil temp as being the "magic" temp. But in a few of the most recent posts you frequently use the word "boiling" and I'm choking on that word. Maybe you just mean "evaporation" and you don't necessarily mean that you actually need to get the oil temp up to 212* (at sea level). But if you intend to say that you recommend that oil temps should get so hot that the water actually boils off ... then I respectfully disagree.

    But I've been wrong before ... only once, though.
    Last edited by Norm; 03-26-2011 at 05:23 AM.

  5. #25
    Senior Member Pete D's Avatar
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    Default Re: Where is the Vernatherm valve on the Stroker 340

    Thats just it, its a rule of thumb, thats why there is a "green arc" instead of a green line. Imagine if you had to operate these air cooled engines with the oil temp between 175 and 185 on every minute of every flight! Just not practical.....

    Pete D.

  6. #26
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    Default Re: Where is the Vernatherm valve on the Stroker 340

    Quote Originally Posted by Pete D View Post
    Affirmative. The brass plug (or vernatherm) would be removed from the oil screen housing and installed in the oil filter adapter if you were putting that on.

    Pete D
    Is it the same for a C4P 180 horse in a cub with the oil filter adapter? I have not been able to get good oil temperatures since it was installed factory new.

  7. #27
    Senior Member Pete D's Avatar
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    Default Re: Where is the Vernatherm valve on the Stroker 340

    Yep, should be the same on that O-360.

    Pete D.

  8. #28
    Senior Member turbopilot's Avatar
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    Default Re: Where is the Vernatherm valve on the Stroker 340

    Quote Originally Posted by Norm View Post
    Turbopilot, good point about the combustion process creating some moisture. Early in this thread in May, 2010, you refer to 180* oil temp as being the "magic" temp. But in a few of the most recent posts you frequently use the word "boiling" and I'm choking on that word. Maybe you just mean "evaporation" and you don't necessarily mean that you actually need to get the oil temp up to 212* (at sea level). But if you intend to say that you recommend that oil temps should get so hot that the water actually boils off ... then I respectfully disagree.

    But I've been wrong before ... only once, though.
    The advice from other engines is that getting the "indicated oil temperature" to 180 dF will likely result in the oil seeing over 212 dF somewhere in the passage through the engine. What I don't know is if this is true for the Stroker 340. Bottom line you want the oil to regularly see a temperature over the boiling point of water (adjusted for pressure) somewhere along it's passage through the engine.

    In other engines I know that seeing an "indicated oil temperature" around 180 dF will assure you that the oil is actually getting well over that temperature in other parts of the engine not being sensed by the oil temperature probe.
    Bob Anderson, CC11-00316, N382RA

  9. #29
    Senior Member randylervold's Avatar
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    Default Re: Where is the Vernatherm valve on the Stroker 340

    Quote Originally Posted by turbopilot View Post
    The advice from other engines is that getting the "indicated oil temperature" to 180 dF will likely result in the oil seeing over 212 dF somewhere in the passage through the engine. What I don't know is if this is true for the Stroker 340. Bottom line you want the oil to regularly see a temperature over the boiling point of water (adjusted for pressure) somewhere along it's passage through the engine.

    In other engines I know that seeing an "indicated oil temperature" around 180 dF will assure you that the oil is actually getting well over that temperature in other parts of the engine not being sensed by the oil temperature probe.
    My understanding from reading countless technical articles, mostly from the oil companies, on this issue is exactly as Bob indicates. Of course we're now getting 'thread creep', this thread is really about vernatherm location rather than oil temp.
    Randy Lervold

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    Last edited by seastar; 10-13-2011 at 01:59 PM.

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