Engineer Ted's How to Make Your Engine Last (ground)

Discussion in 'Maintenance Bay' started by Ted DuPuis, Dec 13, 2012.

  1. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    By (un?)popular demand, here are my tips for how to make your piston engines last, and not. This goes into some of the varying ways of keeping engines happy while they're sitting in the hangar, waiting for you to let them unleash their power and break the surly bonds of earth. We're not talking about running your engine.

    1) Preheating

    Preheating is good for your engine. I personally recommend a full Tanis or Reiff heater setup. My personal preference is Tanis, as I believe they sell a cleaner product, and I also like the fact that they place heat right at the cylinder head (where it's most needed) vs. the cylinder base. Disclaimer: Tanis donated two full engine pre-heater setups to Cloud Nine for the 310. But, we asked them for a donation because we believe in their product. The Aztec had a Reiff setup, and it worked just fine, too. I recommend getting both the cylinder heaters and the crankcase/sump heaters.

    I do not recommend the 100W lightbulb. Although unlikely, this can potentially cause a fire hazard if there is an oil leak, and many of these engines do.

    I also do not recommend use of a "Red Dragon" or similar torpedo-style heater. Yes, this will make the outside of the engine and the cylinders warm to the touch, potentially even hot. Aside from the fact that these heaters may produce too hot of an output that can cause damage under the cowl, they do not heat the core of the engine. Think about this as the difference between putting a frozen casserole in your oven (which I often do since I forget to take it out of the freezer) and setting it at 200F vs. taking a blowtorch to it. The latter will heat it up faster, but if you simply wait until the outside feels warm (which won't take long) and put a fork in it, the center will be frozen. That is exactly what will happen to your engine. One cold night in Canada about 17 years ago, the previous owner of the 310 had the engines pre-heated with a torpedo-style heater. The engines started, and then one engine spun a bearing. Fortunately he had a spare engine, or he would have crashed and likely died.

    There are different theories on when to plug in. I would say definitely below 40F, and any other temperature has benefits still. So this depends on how much you want to go to the trouble of plugging in.

    DO NOT PLACE YOUR PREHEATER ON A TIMER! Placing your pre-heater on a timer will cause the engine's temperature to fluctuate, allowing water to condense in the oil, accelerating corrosion. You hear an A&P tell you that pre-heaters cause corrosion, this is typically the reason. In a very severe accelerated test, we were pulling about 4oz of water out of an engine every day. When the engine was torn down (after only a small amount of run time), there was corrosion on a number of internal parts. Again, this was a very severe case, but remember your engine will be expected to last a number of years.

    Instead, plug your engine heater in the night before you intend to fly. Leaving it plugged in all the time isn't a bad option, either, and Tanis says that there's nothing wrong with doing this.

    Covering up your engine helps keep the heat in the engine, and keeps it warmer as well as help warm up faster. There are varying forms of covers. While the custom-fit ones that cover up the propeller and spinner are the best (remember the propeller and spinner serve as a big heat sink from the crankshaft). However, I don't think that the natural convection that would come off of the prop and spinner matter much. So we just use sleeping bags. Seems to work well - even in -20F outside, the cylinders and oil were a happy 100F.

    2) Dehydrators

    I haven't worked much with engine dehydrators, but we are going to buy some for the 310. The theory behind a dehydrator is to make sure the air inside the engine is as low humidity as possible. This can only help prevent corrosion, especially if you live in a climate that's humid. Dehydrators have a secondary benefit, as well. They will expel the gasses in your crankcase post-shutdown out of the engine. These gasses are not only very high in moisture, but also have corrosive combustion biproducts in them. Not something you want to keep around. They can either be attached through the breather to pump air out through the oil inlet or vice versa. I prefer pumping air out of the breather, since that gets the corrosive gasses expelled from the area under the cowling.

    There are two types of dehydrators - the desiccant style and the dehumidifier style. The former just uses desiccant pellets to absorb moisture, the latter is effectively a dehumidifier. I've gone back and forth on which one I like better, but the desiccant style is certainly cheaper, and I think that will be what we ultimately purchase.

    3) Oil and oil additives

    What oil you put in your engine matters. In one test I saw that looked to specifically identify the ability of oils to protect against moisture. The test was severe, but found that Philips XC 20W-50 by itself had very poor corrosion resistance. Philips XC plus CamGuard or Exxon Elite both had excellent corrosion resistance. As those were the only oils tested, I can't say anything regarding corrosion resistance on the various AeroShell oils.

    A theory I have heard is that, if your engine sits routinely, it is wise to use straight-weight oil rather than multi-viscosity. The theory is that the straight weight oil will stick to the internal parts better, and so you won't develop corrosion as quickly. This theory makes sense, however I believe that the improved lubrication performance from a multi-viscosity oil outweighs the potential negatives, especially if you are taking other precautions to warrant against corrosion.

    One point of note here is that Exxon Elite (as well as Aeroshell 15W-50 and 100Plus) all have the Lycoming "snake oil" additive that is required for certain engines. In Lycomings, this additive is effectively a friction modifier and doesn't hurt anything (especially if you have an H2AD, for which it is a requirement). In Continentals, it can impact the clutches in your starter adapter (unless you have a Continental that doesn't have a starter adapter). While there is some debate over whether or not it truly impacts the starter adapters, we intend on using Philips XC plus CamGuard in the 310's Continentals.

    So if you want your engine to last: get a full pre-heating system that has a heating element for each cylinder, as well as heating elements for the crankcase and oil sump, cover the engine, and plug the heater in the night before you fly (or leave it on all the time). Don't forget to put the covers over the engines. Buy a dehydrator, and use Exxon Elite or Philips XC 20W-50 with CamGuard (and potentially at least certain variants of AeroShell).

    If you want your engine to corrode and fail: put your pre-heater on a timer, then let your engine cold soak and use a torpedo heater on those really cold days to just get the cylinders warm enough. Never bother covering it. Don't use a dehydrator, and just use straight Philips XC 20W-50. Or, for that matter, just use vegetable oil.

    Now the real question: how much does any of this really matter? It is difficult to answer that with a great deal of certainty. I've witnessed and performed a number of extreme tests that, as you would expect, produce extreme results. Most of us don't live in extreme worlds, and our engines don't, either. Corrosion is something that occurs over time in these cases. I have seen people who do everything wrong, and their engines do tend to corrode pretty quickly and have premature failures (although not always). I've also seen people do things partially wrong, but partially right, and they have gotten good service life out of their engines. It's so rare to see someone do everything right that I'm not sure I've seen it done long enough to see a true result, and that includes how I treat my engines.

    That said, I do treat my engines significantly better than most, and have gotten good service life that I attribute to it. With the 310 getting new engines, we'll have an opportunity to, fresh from overhaul, treat these engines with all the love and care that they deserve, and will get to see the results.

    So what should you do? The above lists what the ideal way to do things would be. Engine pre-heaters really are not very expensive as far as aircraft parts go, and sleeping bags are even cheaper (or you can buy a fancy custom engine cover). You can make a dehydrator yourself (cheap), or buy one of the commercially-available ones (less cheap). You need oil anyway, so it makes sense to choose something that's less prone to corrosion.

    For what it's worth, what we're planning on the 310's new engines is to continue using our Tanis heaters (plugged in the night before any trips), keep sleeping bags over the engine nacelles and stuffed in the nose plugs to keep the heat in, have a dehydrator forcing dry air through the oil filler and out of the breather, and use Philips XC 20W-50 with CamGuard.
     
    Last edited: Dec 14, 2012
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  2. Henning

    Henning Ejection Handle Pulled

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    According to Ed Exxon Elite is the same as Aeroshell semi synthetic. Phillips with Cam Gaurd is what I run as well. I like heating the whole hangar a few hours ahead of time.
     
  3. AggieMike88

    AggieMike88 Touchdown! Greaser! PoA Supporter

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    Now offering reverse discounts.
    Added to thread subscriptions. Thanks Ted!
     

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  4. douglas393

    douglas393 Pattern Altitude

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    I hangar in southwest florida, and except for a few days in late January, and February the temperature is rarely below 50 degrees. So when would you recommend that I heat the engine compartment or my Hangar?
     
  5. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    I'm curious about a couple of things:

    1) You end up needing the spark-plug-hole CHT probes when you have a Tanis, right? Are there any disadvantages to those?

    2) Won't the bands around the cylinders more evenly heat the entire engine via conduction as opposed to the CHT-probe-hole heaters which are in a pretty small spot and about as far away from the rest as we can get?

    Are you putting a sleeping bag over the prop/spinner, or just over the top of the cowling? I have a blanket for the cowl (and cowl plugs), but I have a sleeping bag I could put over the prop and spinner too, if it'd really be effective. (Been a bit too long since Thermodynamics and Heat Transfer for me. ;))

    FWIW... We use Aeroshell 15W-50 in all of the club planes. (Not my choice - I'd have switched the 182 to something else, but I'm not the Mx officer). We had some issues starting the 182 - It'd always only crank over one blade and then stop on the first attempt. The second time, it'd reluctantly turn over the second blade and keep going. We replaced the starter, battery, cabling, etc. with no effect. Finally, we replaced the starter adapter. The plane started GREAT afterwards... But within 3 months or so (and probably 50-75 hours on the engine), it was back to how it had been. So, count me in as a believer that the snake oil isn't good for Conti starter adapters.
     
  6. Arbiter419

    Arbiter419 Cleared for Takeoff

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    Good information, thanks Ted!
     
  7. LDJones

    LDJones Touchdown! Greaser!

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    We generally use freezing point as a guide although some will say the 20s are okay. It never hurts to preheat but I wouldn't waste the energy at 50F.
     
  8. poadeleted20

    poadeleted20 Deleted

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    That's the same Ed who owns the company that makes CamGuard, right? Consider the source. Also, consider Aviation Consumer's independent corrosion tests which showed that straight Exxon Elite was significantly superior to straight Aeroshell 15-W50. but once CamGuard was added to Aeroshell 15-W50 the difference with straight Exxon Elite in those tests was not significant.
     
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  9. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    The problem with heating the whole hangar a few hours before is the fact that everything that really matters is burried deep within the airplane. Further, to really be optimal, the engines want to be hotter than the rest of the aircraft for optimal pre-heating. So really, you'd want to heat the hangar up the night before.

    I'll just stick to the engines, myself. But a heated hangar sure is nice...
     
  10. Henning

    Henning Ejection Handle Pulled

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    No, us Florida residents can save the energy, I see no need in a preheat at 50.
     
  11. Henning

    Henning Ejection Handle Pulled

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    LOL, the source is the guy Exxon management called upon to formulate the "ultimate aviation oil" in their lab at their expense on their payroll. When completed the same management said "That's gonna be too expensive, let's just use the Aeroshell formula, it sells well and will make a bigger profit." that's when Ed went on his own with Camgaurd. So yeah I've considered the source, now you consider the sources.
     
  12. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    None that I'm aware of.

    Remember that a full Tanis system has heaters on the top of crankcase, bottom of sump, and each cylinder in the CHT port. Now think about the areas you most want to get heated. Those areas are the cylinder head (as close to the combustion chamber as possible, which is where the heat is produced), the oil (warm oil means it will get through the engine quickly), and the crankshaft (to get bearing clearances where they should be). The Tanis system will provide better heating to the cylinder head, which is what matters most. It replicates the heating the engine will receive better as well by putting the heat source closer to the source of combustion. The crankcase and sump heaters handle getting heat to the oil and crank. Plus, if it's covered up, then the heat should end up being relatively uniform after a few hours.

    Just over the top of the cowling, and then I stuff the sleeping bag in through the cowl plugs. I don't think the spinner and prop will cost you enough heat to matter myself. If you're outside, then maybe a bit more with the wind providing more convection.

    That seems right from what others have reported as well. The right engine on the 310 needed a starter adapter, and I wasn't very good, especially at first, about being picky on which oil I put in.
     
  13. flyingmoose

    flyingmoose Pattern Altitude

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    Good write up Ted!
     
  14. tmyers

    tmyers En-Route

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    Ted,

    I understand that Tanis provides several options for engine preheat. Since I am preparing to install an engine monitor I was going to use the threaded well for the CHT sensor. You state that heat is needed at the bottom of the sump so I am assuming you are referring to the heater pad that adheres to the pan. Heat is needed at the CHT port of each cylinder, and also at the top of the crankcase.

    I really would rather not use spark plug washers for CHT so I am considering purchasing the dual purpose inserts that will heat and give me CHT readings. What is your experience with these items or would it be best to just use the washer style sensors.

    Lastly is the top of the crankcase. Which Tanis part are you referring to here?
     
  15. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    The 310 has Tanis systems that use heaters at the CHT ports (with the provision to allow use of our normal JPI sensors) and two heating pads - one on the sump and one on top of the crankcase. The two heating pads I believe are identical. I wouldn't do the CHT probes under the spark plugs. The setup we have has over 400 hours on it with zero problems.

    I would recommend the same setup for anyone else. If you call up Tanis, I'm sure they'd be glad to help you with the exact system that fits your needs.
     
  16. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    I guess to my way of thinking, if the bands or the bolts are at the same temperature, they'd be roughly equal - The bolts are on the side and closer to the top of the cylinder, but the bands are all the way around which I would think would be an advantage (heating the entire perimeter of the cylinder evenly).

    Reiff does not have a pad on top of the crankcase, but with the heat from the bands being closer, I doubt that matters.

    Of course, you're spot on here:

    Bingo. Conduction is the most efficient method of heat transfer (that I do remember!) so at least in my case it won't matter - I'm going to keep it plugged in all the time.

    I wouldn't think so either, but it'd be cooling the crank, mostly. The question is whether it cools the crank enough to promote condensation. The dryer would make a big difference here, since if the crank isn't cool enough for moisture to condense on it, I would think that a cold crank at startup isn't a big deal - It'd actually have slightly more clearance than normal, wouldn't it?

    I'll have to see if there's a detectable level of heat at the root of the prop blades. I'm in a very well-sealed hangar, so I doubt it'll be an issue. It'd be neat to have one of those heat cameras, tho... Wonder how much those cost?
     
  17. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    I think Tanis has different types of cylinder heating elements. The ones that plug into the CHT port heat right near the center of the cylinder head, where it matters most. I think you're talking about a different kind of heating element.

    I think this is where people get into the realm of picking fly turds out of pepper. I've never noticed a detectable amount of heat on the prop, even after shutting down and letting a prop heat soak a bit. So I think the amount of heat lost is virtually zero, and as such your risk of condensation would be about the same.
     
  18. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    They do have different types. I was speaking of the ones that go into the CHT port. They also do have ones that "take the place of one of the rocker cover bolts in each cylinder".

    My point was simply that I think a band would provide more even heating than a probe in a single spot. But, as you mentioned, it's all pretty much moot if they're left plugged in and covered, as conduction should even things out pretty well after a while.

    I would think so too - But you know, being an engineer, that we tend to be curious about these things even if they're insignificant. ;)
     
  19. tmyers

    tmyers En-Route

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    Just spoke with Tanis and they did not recommend the top element since I have a 4 cylinder. They also suggested that I use the intake bolt inserts for cylinder heat instead of the combination CHT sensor heating element in the cylinder head.

    $720.
     
  20. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    BTW, here's the reasons I chose Reiff over Tanis:

    1) Tanis' system for the Continental IO-550 with an engine monitor installed costs $1,080. Reiff's costs $595.

    2) Personal experience. We needed a new heater on the 182 when we had the engine overhauled a few years ago. One of our club officers, a former P210 owner, suggested the Reiff based on his (good) experience with it on the P210, so we had one installed. A year later, we installed one on the Diamond after we bought it. Both have been trouble-free and keep the engine nice and toasty warm in the winter - We use cowl plugs but no blankets or any other insulation on the club planes, and it's warm enough in there that when my hands get cold on a winter pre-flight I stick 'em in the oil door to warm them up!

    I have nothing against Tanis, I've heard good things about them too - There's just more issues to worry about due to their potential conflicts with engine monitors, and they cost more as well.

    The most important thing in any case is to make sure that you heat the engine, and heat the *entire* engine, not just the oil.
     
  21. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    FWIW, the Reiff standard system (heats all cylinders and oil sump) for your plane is only $435.

    http://www.reiffpreheat.com/product.htm#System Summary
     
  22. jesse

    jesse Administrator Management Council Member

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    I've been planning on getting the Reif system for the Flybaby. But I'll probably have to settle for something less than ideal for awhile.
     
  23. tmyers

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    Does the heat get to where it needs to be with the bands around the cylinder?
     
  24. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    Even heating in the wrong area still heats the wrong area. :)

    True, and I've determine the answer to my satisfaction.
     
  25. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    See my previous posts - Yes.

    Whether you have Tanis or Reiff, you need cowl plugs at the minimum - But with either system, if you have plugs in, the entire engine will be warm.

    IMO, if you did not have plugs in, while the Tanis will put heat "closer to where you want it" (paraphrasing Ted), it would be somewhat uneven - And both are undesirable.

    Use cowl plugs, and buy whichever system suits you. We've had great experience with the Reiff heaters on the 182 and DA40, and now I have another Reiff getting installed on the Mooney today.

    I certainly wouldn't take a Tanis off a plane to put the Reiff on, but given the lower price of the Reiff and lack of conflict with engine analyzers, I'll probably continue to choose them for new installs, since the differences in how the engine is heated in practice will be negligible.
     
  26. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    Only if you're picking fly turds out of pepper. ;)
     
  27. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    Well, heating will be somewhat uneven anyway. Also, heating is definiitely uneven when the engine is running. :)
     
  28. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    Which is kinda my point with your comment. ;)

    Just got back from the airport and learned I actually didn't know which tanis heaters we had. We have the ones that bolt to the cylinder and heat there. I still like that better than the Reiff setup since the head it was what really needs to get heated on the cylinder anyway.

    Learn something new every day. It helps when you keep on forgetting stuff.
     
  29. tmyers

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    My company owns a Flir infrared camera. This is the device that Tanis used to produce the picture of how well their engine pre-heater warmed the engine. What ever I get I will a picture of how the heat is spreading throughout the engine. That would be cool to see how well or how bad the system works.
     
  30. AdamZ

    AdamZ Administrator Management Council Member

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    Ted good information. Question, is it better to just not preheat than use a red dragon type system? You know the PA28 I usually fly is tied down in SE PA. Perhaps not a cold as Vermont but it does get cold. We preheat with a knock off red dragon. No electric at the tie down so we can't plug in. If we waited for it to get above freezing our breakfast run might not take place until 2pm if at all. So would we be better off not preheating or even not flying?
     
  31. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    The issue with the Red Dragon is that it will get the cylinders warm, but not the oil and the crankshaft/bearings. As such, your engine will start (and probably even seem to run pretty well), but the oil will still be cold, as will the crank and bearings. As such, it will take the oil a while to get circulated, which means that much longer that the engine isn't running with oil. This is bad for it and causes premature wear to the bearings.

    I wouldn't say you'd be better off not preheating. Some of that heat is making it to the oil, so it is better than nothing. The case where the previous owner of the 310 had an engine spin a bearing and ultimately seize up after takeoff was something of an extreme one. It was so cold, the props wouldn't even turn by hand when he got to the plane initially. Obviously, you aren't talking about that kind of temperature.

    As far as whether or not to go, that's a call you have to make. Yes, cold starts do some damage to the engine. How much damage they do depends on the severity - I've witnessed some pretty decent damage pretty quickly. It's also worth noting I've had nights when I either couldn't or didn't plug in the Aztec, got out to it the next morning at 10F, and then fired the thing up and, after a good warm-up, off I went. 1,000 hours later with the right engine past TBO, still running fine.

    So were it me, I'd go anyway. Then again, I typically had a mission I had to attend to. Whether or not you want to go is a call you'd have to make. Since the PA28 you fly is pretty much for pleasure use anyway, if there's not any pleasure getting had out of it, then what's the point?
     
  32. David

    David Pre-takeoff checklist

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    My red dragon heater warmed the oil, at least according to the oil temperature gauge. Here's the results from a few years ago warming up the IO470C in my bonanza. The oil temperature was up over 80F in 25 minutes. The CHT, an average of the six cylinder head temperature probes, was up even more. I don't particularly like using the red dragon so I put a Reiff Turbo system on. I'm using the red dragon on my gipsy major and it still works.

    TIME OAT OIL CHT

    0 35 35 35
    12 35 63 100
    20 35 83 142
    25 36 118 167
     
  33. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    35F isn't very cold, and 80F on oil isn't that warm. 30 minutes is also a long time to use the thing. :)
     
  34. David

    David Pre-takeoff checklist

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    I thought you said the Red Dragon wouldn't heat the oil :confused:. You're right 35F isn't a very cold ambient starting temperature however a delta T of over 80F in 25 minutes shows quite clearly that it does work.

    The problem I've seen with most hot air heaters is that people simply don't leave them on long enough.
     
  35. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    Sorry, I should go back and edit. The majority of the heat goes into the cylinders, and when not used for a long period of time you won't see a noticeable difference in oil temp. I'd consider 25 minutes longer than I'd be willing to use it for - most people do about 5 minutes from what I've seen. At 5 minutes, you'll get the CHTs warm enough, but barely touch the oil.
     
  36. timwinters

    timwinters Touchdown! Greaser! PoA Supporter

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    Ted,

    Just some data points.

    I run my Salamander set-up for 30 to 45 minutes anytime the OAT is 40* or less. It provides a reasonably even heat for the entire engine compartment and raises the oil temps 25* to 30* above ambient. (@Dave, this is the temp immediately after starting the engine. My oil temp will read 10* higher than it actually is before starting because the sensor is externally mounted, but the temp drops immediately upon starting).

    I believe my set-up is better than the red dragon for two reasons. First the heat source is farther from the engine so the air entering the cowl isn't so hot and, second, I'm introducing the warm air into the bottom of the cowl and allowing it to naturally rise instead of trying to force it down from the top.

    The Achilles heel of my system is the internal engine components...crank and bearings, etc. There's a lot of mass there that I know I'm not warming much if at all.

    My question, Ted, is: At what temperature does this become an issue? (internal components still being cold) How cold must it be before we need to worry about clearances and possibly re-cooling the oil? What else is there that's of concern with cold "innards"?

    The hangar has electric and I could install a Reiff or Tanis but they're not nearly as convenient for spur of the moment trips...like 90% of mine are theses days.

    Here's my system, again:

    [​IMG]
     
    Last edited: Dec 15, 2012
  37. denverpilot

    denverpilot Taxi to Parking

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    What is the reason you wouldn't use it for more than 25 minutes? Are you saying that is inconvenient, or you'd be worried about the device?

    I typed this up earlier but hadn't sent it yet...

    I have similar questions to Adam. Lets just say that my entire life has been "less than ideal" as have most other people's, so... A "less than ideal" pre-heat setup, fits right in. ;)

    (I do try to make things ideal, but hey... Limited funds, time, and interest are all part of the human condition. Heh.)

    We don't have electricity at our hangar. We have a homebrew propane heater setup.

    My typical use is to have it on for a significant portion of 30 minutes, and in extreme cold weather, maybe longer. Power is from a generator or inverter hooked to ground based vehicles.

    I will also add here that this is always done with a large (not one of those piddly little kitchen fire things) fire extinguisher close at hand, and since I generally fly recreationally, it's rare to do the "extreme cold" thing. If it ain't fun, why do it? Life's too good for that.

    Anyway, continuing with questions...

    Even for those with with electric, what do you do at out stations? It's not like many FBOs will let ya run an extension cord out onto the ramp. If you're using the aircraft for real travel, and doing it in the winter, you're going to have some cold starts. There's very little opportunity to avoid it.

    (Case in point: I took my entire pre-heat setup to Lincoln when I flew with Jesse last year. It never got used. It was not convenient to get power to it, nor to drag it from the rental car to the flight line every day/night. Nighttime temps were zero or lower. The FBO was kind and did hangar the airplane a number of nights without charge -- helps to be buying that much fuel in a week, I suppose. Plus they're just very nice people there -- but the airplane was cold started at least a few times. It was basically unavoidable.)

    As far as oil goes, we're Aeroshell 15W50 users here as are tons of the flight schools and others. On a Continental. I know, I know, the world may come to an end. When we learned of Camguard and saw hard evidence that it really does work, we started using it. Airplane has been using Aeroshell 15W50 for over a decade. Frankly with our wild temperature variations, having something with a feedstock that's 15 or lower is pretty important to us, which we've discussed once amongst the co-owners. 20W is a bit sluggish in the cold months.

    So there's our reality.

    We'll report eventually on when the engine dies. It's an O-470S so everything I've read is that the normal/usual death for a non-abused O-470 is the bottom end starts making metal somewhere, sometime a few hundred hours after TBO on average. We shall see. It had a cylinder replaced long ago... First owner. Sea level. I suspect from running it too lean.

    Even more interesting, it's got orange-banded chromed cylinders, which I've seen many folks don't like to use anymore, but are recommended on lightly flown aircraft sometimes for corrosion control. Since its so dry here, that's almost never an issue on any part of most aircraft here, per our mechanics. Dry rot of rubber is a much bigger problem overall, to show how rare it is.

    Oil burn is under 2 qts in 35 hours and usually we can get away with 1 qt added per oil change.

    Oil analysis has only ever shown two things, once the air filter had an undetected hole sliced in it and silicon went up slightly, and one oil change ago a tiny rise in aluminum was detected which Blackstone said we should monitor and could be from the oil dipstick itself. A seriously tiny number.

    Okay back to the questions...

    If some enterprising person were to figure out a way to fire up a generator for a period of time prior to a flight to power an *electrical* pre-heat system, obviously if the genset were in a safe location away from combustibles, monitored, etc... What's the minimum amount of time it would have to be on -- to heat at least some "non-ideal but better than that propane burner" portion of the engine?

    Ted said Aeroshell with Camguard is close enough to his recommendation. I liked that.

    Not really a pre-heat question, but is there any hard data yet on engine longevity between X, Y, and Z oil brands all with CamGuard added? Or is that picking poop out of... Whatever. ;)

    I'll throw a final note out here... Most of our clubs don't have pre-heat rules until things get incredibly cold. Many of their aircraft in today's economy don't fly any more than ours does. AFAIK, I'm not hearing many stories of premature engine death on the rental fleet, but will admit I'm not as in tune to the rentals as I once was. Their aircraft also sit outside. Pre-heat in the wind with a propane burner isn't going to be very effective, and I've never seen a rental with cowl plugs. (We do have those, BTW.)

    Just random questions and thoughts. It's fairly unlikely we will be able/willing to change much about our procedures but I do enjoy the discussion.
     
  38. denverpilot

    denverpilot Taxi to Parking

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    p.s. Not easy to edit from Tapatalk, but I will add that during the intensive instrument training plugging around for hours at 90 knots (low power settings) we saw a 1 qt rise in oil consumption in 35 hours or so.

    This data may be skewed by the fact that we ran it over the usual oil change hours for that particular oil change because it was not convenient to change oil in winter in Nebraska so the number may average back down in the data on the next change... I forgot to look. I wouldn't count on it being that accurate, but maybe worth mentioning.
     
  39. Gary

    Gary En-Route

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    Ted:

    Appreciate you doing these write-ups, always informative and fun to read. As Adam mentioned, we use a small propane heater on those cold mornings. It's a small unit and fits below the cowl and blows the hot air upward. I generally aim it at the oil pan. It doesn't blow the air in through the cowl plugs. In a perfect world, I'd have a weather tight hanger and electric power, all kinds of pre-heat options then. I agree completely with your conclusion (at least I THINK that is your conclusion) that getting the oil as warm as possible is the key. I'm sure we could do a bunch of heat transfer calculations, but plain common sense seems to indicate that applying heat directly to the oil pan (just like the stick-on pad heaters) would be of great help in getting the oil temps up. Don't need to get it to 100F - none of us would think twice about starting up if ambient temps were 50F. Generally, a good 20-30 minutes gets the surfaces nice and toasty, but I really don't know what the internal temps of the main bearings/crank would be, but I'm pretty confident that they will be greater than 30-35F. While not ideal, it's the best I can do with what I've got.

    Sounds like a good opportunity for a test! Thread a thermocouple down the filler tube and measure temp over time!

    Gary
     
  40. Henning

    Henning Ejection Handle Pulled

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    What about the rocker cover ring heater bands? I always liked those.