Constant Preheat?

[Tom-D]

Vapor pressure of the oil in the crankcase displaces the oxygen required for corrosion. The water in the crank case mixing with combustion byproducts suspended in the oil as it makes its way through is why oil sumps corrode through.

Vapor pressure has nothing to do with corrosion or the ability to displace O2, which by the way is not needed for corrosion, the corrosion occurring at the bottom of the oil sumps is covered by a layer of oil and has no contact with air. or 02.

 

[N801BH]

Vapor pressure has nothing to do with corrosion or the ability to displace O2, which by the way is not needed for corrosion, the corrosion occurring at the bottom of the oil sumps is covered by a layer of oil and has no contact with air. or 02.

Huh..

If the bottom of the pan is covered in a layer of oil and preventing water or air from reaching the metal to cause corrosion... What is the problem???

 

[Hank S]

No, not flying the aircraft is the worst thing I can do. Without the engine heater I won't be flying a whole lot through midwestern winters. I would rather have a cellphone remote hooked up to the thing but haven't the requisite electronics expertise to obtain and install one.

Buy a cell switch like this one (http://switchboxcontrol.com/the-switch-box/ I am a satisfied customer!), plug it into the wall, plug your engine heater into it. If you have that much expertise, all that's left to do is call the number a couple if hours before you fly.

The only expertise needed is installing the heater, which you have. Cell switches let you turn the heater (or anything else) on and off without going to your hangar / barn / other place.

Thus is but one manufacturer, exercise your google-fun and find others. This one works well for me.

 

[txflyer]

An engine de-humidifier is on my list.

We get 100% humidity down here sometimes...

The rest of the time it's like 90% in summer ...

 

[Henning]

Well, I certainly wouldn't drink it, But I'm no chemist, to tell you what is in it.

Try this, add equal parts water, liquid soap, and engine oil. shake it until it turns milky. set it in a warm window and see what happens. you'll understand what happens in your engine after the water reaches the oil sump.

I got the whole list from Ed. It's long, and Camguard is formulated to deal with them.

 

[Henning]

Vapor pressure has nothing to do with corrosion or the ability to displace O2, which by the way is not needed for corrosion, the corrosion occurring at the bottom of the oil sumps is covered by a layer of oil and has no contact with air. or 02.

It gets the oxygen for corrosion from the acidic water in the bottom of the sump. All corrosion is a process of oxidation. If oxygen is replaced by a hydrocarbon, oxidation cannot occur. The same effect is why we inert tankers with exhaust fumes so they don't explode during static discharges. Corrosion is slow oxidation, fire and explosions are rapid oxidation. The processes themselves are the same and both require oxygen.

 

[sourdough44]

What's the difference between pre-heating to 70 degrees or a plane in Florida that stays that temp year 'round?

Edit: Assuming the whole case, etc is at 70 degrees. I don't think the oil is at a point where the viscosity is low enough to remove it from all surfaces.

I think the big difference here is temperature variation from engine core/oil to ambient. When it's 20 degrees in the room and the engine is heated to 60 or whatever there will be temps all in between. Not really saying it's a major problem longer term.

It's somewhat in reverse when you gave a sudden warmup on a cold engine, allowing condensation to form on cold soaked metal.

I'm ten miles away, so I plug in the day prior.

 

[kyleb]

I think the big difference here is temperature variation from engine core/oil to ambient. When it's 20 degrees in the room and the engine is heated to 60 or whatever there will be temps all in between. Not really saying it's a major problem longer term.

Which brings to mind the question of why sticking a 100w bulb under the cowling (with the cowl covered with packing blankets, etc.) and leaving it on all winter wouldn't be a good solution. Sure, it would cost you a quarter a day for electricity, but in the big picture...

Presumably, the bulb would heat the entire engine compartment to ambient plus 20 (or whatever), driving engine compartment humidity way down. Leave the oil cap off and the engine internals would dry out too (although evaporation through the breather would probably take care of it anyway).

Ted, any comments?

 

[coloradobluesky]

Sometimes airplane carbs and fuel injectors leak gasoline. Make sure the heater wont ignite leaking gas. Consider turning fuel to OFF.

 

[Ravioli]

When I was flying out of St Louis some people would leave a shop light under the cowl with a blanket over the top and that would keep the whole engine compartment provided with some heat.

Others would leave an electric heat blower under the engine compartment blowing up into it.

Seems these would be safe "constant pre-heat" as apposed to the preheat pads that are only heating the oil in the pan.

And since I'm about to be a new owner I'm really curious about this. My plan is that it will be kept so close that I can drive 5 minutes the night before and not worry about it.

 

[kyleb]

Seems these would be safe "constant pre-heat" as apposed to the preheat pads that are only heating the oil in the pan.

The pads heat a lot more than the oil in the pan. I went flying on Friday. Stopped by the airport at about 1:00 and plugged in the pad heater (it was ~39F at that time, with a high later of 42 or thereabouts). Got to the airport at 5:00, unplugged everything, fired up the airplane, and the digital CHT and oil temperature gauges both registered in the mid-70's. With a longer preheat (and a cowl blanket), I routinely see oil temperature and CHT's in the 90's and sometimes above 100F on 30F mornings.

 

[Tom-D]

Which brings to mind the question of why sticking a 100w bulb under the cowling (with the cowl covered with packing blankets, etc.) and leaving it on all winter wouldn't be a good solution.

Ted, any comments?

Let's say you do that and the engine internals get warm/hot.

What is going to vent the cases to carry the moisture away. ??

Most of the Lycoming 0-/IO series we see in GA the oil filler tube enters the engine at a very low point on the cases very near the sump. you heat the engine and the vapors will rise to the cam and stay there, cause there is no way out.

TCM on the other hand places the oil filler at the top of the cases. Still if there is no flow thru the cases the vapors will stay in the cases.

So Why preheat at all?

 

[N801BH]

Let's say you do that and the engine internals get warm/hot.

What is going to vent the cases to carry the moisture away. ??

Most of the Lycoming 0-/IO series we see in GA the oil filler tube enters the engine at a very low point on the cases very near the sump. you heat the engine and the vapors will rise to the cam and stay there, cause there is no way out.

TCM on the other hand places the oil filler at the top of the cases. Still if there is no flow thru the cases the vapors will stay in the cases.

So Why preheat at all?

Ya gotta love CERTIFIED aircraft engines.......

 

[3393RP]

If constant heating creates corrosion then why does every legally required standby generator have a block heater? The NFPA codes require it. I have bought and resold gensets that were thirty years old and the internals looked like new.

 

[kyleb]

Let's say you do that and the engine internals get warm/hot.

What is going to vent the cases to carry the moisture away. ??

The ideal gas law doesn't really care where the crankcase is vented, as long as it is vented, so the breather is fine. But if you're concerned about it, crack the oil cap.

 

[Tom-D]

If constant heating creates corrosion then why does every legally required standby generator have a block heater? The NFPA codes require it. I have bought and resold gensets that were thirty years old and the internals looked like new.

A standard that is applied to all gen-sets by the coldest application.

Hay guys we could be designing this for Prudo Bay, we need heaters in all gen-sets, guy in south Fl,is wondering what this wire is for

 

[Henning]

If constant heating creates corrosion then why does every legally required standby generator have a block heater? The NFPA codes require it. I have bought and resold gensets that were thirty years old and the internals looked like new.

Good point, and the big difference is the water jacket. With a block heater and a water jacket everything is heat soaked, as I said earlier, if you want to use continuous preheat, just keep everything well above the dew point and you have no problems. Typically generators are housed in enclosures where the block heat keep the entire enclosure at 70° when it's -40°. You aren't just preheating locations on an engine with cold spot potential, you are keeping it in a fully climate controlled environment.

 

[Tom-D]

The ideal gas law doesn't really care where the crankcase is vented, as long as it is vented, so the breather is fine. But if you're concerned about it, crack the oil cap.

The "Ideal gas law" isn't ideal in engines, proven by the amount of corrosion we see in the closed cases of aircraft engines.

How does opening the filler cap in a Lycoming help?

Next time you are near one, look see where the filler tube enters the cases.

 

[Henning]

The "Ideal gas law" isn't ideal in engines, proven by the amount of corrosion we see in the closed cases of aircraft engines.

How does opening the filler cap in a Lycoming help?

Next time you are near one, look see where the filler tube enters the cases.

If you connected the breather tube to the Oil Fill, and leave the breather on the top of the engine open, you would help. The heated block would create a draft pulling in cold, dry, air, heating it in the case to absorb water and leave through the vent.

 

[Tom-D]

Ideal gas law
From Wikipedia, the free encyclopedia
The ideal gas law is the equation of state of a hypothetical ideal gas. It is a good approximation to the behaviour of many gases under many conditions, although it has several limitations. It was first stated by Émile Clapeyron in 1834 as a combination of Boyle's law and Charles's law.

A good approximation of a hypothetical ideal gas..... yeah right.

If you believe that is what happens in your engine I have a bridge for sale.

 

[kyleb]

The "Ideal gas law" isn't ideal in engines, proven by the amount of corrosion we see in the closed cases of aircraft engines.

How does opening the filler cap in a Lycoming help?

Next time you are near one, look see where the filler tube enters the cases.

Tom, the vent location doesn't matter so long as the crankcase *is* vented. The hotter than ambient engine will drive off the moisture, resulting in an engine with substantially lower relative humidity than ambient.

 

[Tom-D]

If you connected the breather tube to the Oil Fill, and leave the breather on the top of the engine open, you would help. The heated block would create a draft pulling in cold, dry, air, heating it in the case to absorb water and leave through the vent.

If you want to go to all that trouble, you might better use a disci-cant filter and purge the engine with N2.

When we preserved engines for the Navy's open ocean shipment we would run them on the test cell with a mix of 1010 press oil and grade 4 paralketone drain, then place them in a container and purge with N2 until the disacant indicator turns blue. that was good for 30 days, between inspections.

 

[Tom-D]

Tom, the vent location doesn't matter so long as the crankcase *is* vented. The hotter than ambient engine will drive off the moisture, resulting in an engine with substantially lower relative humidity than ambient.

Don't you believe that for a minute, I've tried that over and over it simply doesn't work.

The 0-300/0-200/0-470/0-520 all have filler caps that are mounted high in the case, they will allow steam to escape when the engine is hot, simply because they have a breather separate from the filler which will allow the escaping hot gas to be replaced with cooler gas from a different source.

Lycomings will not, due to the location of the filler tube. Heating the Lycomings will send the steam directly to the top of the engine, which is the top of the accessory case and the Mag gears/impulse coupling and cam in the major case.

 

[Henning]

If you want to go to all that trouble, you might better use a disci-cant filter and purge the engine with N2.

When we preserved engines for the Navy's open ocean shipment we would run them on the test cell with a mix of 1010 press oil and grade 4 paralketone drain, then place them in a container and purge with N2 until the disacant indicator turns blue. that was good for 30 days, between inspections.

I quit using desiccant filters like that, they cause corrossion problems as well. As the air draws through them during weather/temp changes, it draws in some corrosive stuff. I found some problems with some stored engines from that.

If I'm parking an engine for a while, I add a big dose of Lucas Oil Treatment and give everything a good coat. At this point, that is the best product I have found. Combined with fogging spray I'm getting pretty good results with storing engines even down here.

 

[Tom-D]

Note where the filler tube in this 0-360 enters the case.

Way below where the moisture vapors will be when you heat the engine.

 

[Tom-D]

I quit using desiccant filters like that, they cause corrossion problems as well. As the air draws through them during weather/temp changes, it draws in some corrosive stuff. I found some problems with some stored engines from that.

If I'm parking an engine for a while, I add a big dose of Lucas Oil Treatment and give everything a good coat. At this point, that is the best product I have found. Combined with fogging spray I'm getting pretty good results with storing engines even down here.

Well good luck with the snake oils.

you must use a different filter than we use, we use the filter and it's color as an indicator, not a filter. we place it at the discharge rather than the intake, then purge with dry N2. when all the water is gone the discharge disacant will turn blue. then cork up the engine, place dryer plugs in the upper spark plugs and watch them, if they turn pink, we do it all over again, until all indicators stay blue.

When I bought my spare Warner 165, It came in a steel can, with a disacant indicator, the engine was brand new never run, and preserved by the factory in 1943. the indicator was still blue. I wish I had never broken the preservation, but the engine was still the same as it was the day it went into the can.

There is no better way to preserve any engine than the disicant method of monitoring the interior.

 

[Tom-D]

I quit using desiccant filters like that, they cause corrossion problems as well. As the air draws through them during weather/temp changes, it draws in some corrosive stuff.

I believe that is just wrong.

 

[Henning]

Well good luck with the snake oils.

you must use a different filter than we use, we use the filter and it's color as an indicator, not a filter. we place it at the discharge rather than the intake, then purge with dry N2. when all the water is gone the discharge disacant will turn blue. then cork up the engine, place dryer plugs in the upper spark plugs and watch them, if they turn pink, we do it all over again, until all indicators stay blue.

When I bought my spare Warner 165, It came in a steel can, with a disacant indicator, the engine was brand new never run, and preserved by the factory in 1943. the indicator was still blue. I wish I had never broken the preservation, but the engine was still the same as it was the day it went into the can.

There is no better way to preserve any engine than the disicant method of monitoring the interior.

Problem with that around here is you would have to keep adding N2 because everything breathes, so people put the desiccant bags at all the points of ventilation.

Lucas works very well at providing a thick, stable, film. Even Ed thinks it's a good product for the storage application. After it settles in it forms a cosmoline like film.

With Diesels, I fog the cylinders and put the injectors back in.

 

[N801BH]

Note where the filler tube in this 0-360 enters the case.

Way below where the moisture vapors will be when you heat the engine.

What someone needs to do it fabricate a "vented push rod tube".. Since it is at the top of a Lyc and would vent the crankcase properly.... All you would need is just one tube vented to keep the install simple...

Get an STC and that person could make a fair sum of money.......IMHO.

 

[Tom-D]

What someone needs to do it fabricate a "vented push rod tube".. Since it is at the top of a Lyc and would vent the crankcase properly.... All you would need is just one tube vented to keep the install simple...

Get an STC and that person could make a fair sum of money.......IMHO.

How would you vent past the lifter?

 

[N801BH]

How would you vent past the lifter?

It has been 30+years since I looked closely at a Lyc, but I thought the oil was transferred to the rockers , springs and guides through the inner part of the push rod it self and that oil returned to the crankcase back down the pushrod tube.. No ???

 

[kyleb]

What someone needs to do it fabricate a "vented push rod tube".. Since it is at the top of a Lyc and would vent the crankcase properly.... All you would need is just one tube vented to keep the install simple...

Get an STC and that person could make a fair sum of money.......IMHO.

The location of the vent doesn't matter. With constant heat, there wouldn't be an internal temperature gradient to cause vapors to rise. The vapors would simply migrate out of the available vents to equalize the partial pressure of airborne H2O with the outside atmosphere.

 

[N801BH]

The location of the vent doesn't matter. With constant heat, there wouldn't be an internal temperature gradient to cause vapors to rise. The vapors would simply migrate out of the available vents to equalize the partial pressure of airborne H2O with the outside atmosphere.

I respectfully disagree...

Convection is your friend. Especially when you have a stagnant flow in a crankcase..

 

[ggroves]

What say you?

I used the exact same setup for years on a 182RG. Un-metered electric in the hangar. Ran it 24/7 from Nov. thru Apr, with a blanket over the cowl. The airplane flew once per week at a minimum. Former partner still uses the same setup today, so 15 years and no problems. Change out the heater (we used a cube heater) ever other year.

It's nice to start out with a warm engine.


Sent from my iPad using Tapatalk

 

[Tom-D]

It has been 30+years since I looked closely at a Lyc, but I thought the oil was transferred to the rockers , springs and guides through the inner part of the push rod it self and that oil returned to the crankcase back down the pushrod tube.. No ???

no, the lycoming has drain tubes from the rocker box to the sump. that is the blue fitting in the picture.

 

[N801BH]

no, the lycoming has drain tubes from the rocker box to the sump. that is the blue fitting and tube in the picture.

Ok... It has been a while....

 

[Henning]

no, the lycoming has drain tubes from the rocker box to the sump. that is the blue fitting and tube in the picture.

yeah, you have to go out the top. What is needed is a breather input down low so it can suck in cold, dry air.

 

[Tom-D]

yeah, you have to go out the top. What is needed is a breather input down low so it can suck in cold, dry air.

Don't be dumb, that's a major alteration of the engine, all you really need to do is use a oil that will protect on start up, and leave the water in the sump until you go fly.

 

[Henning]

Don't be dumb, that's a major alteration of the engine, all you really need to do is use a oil that will protect on start up, and leave the water in the sump until you go fly.

Yeah, I wouldn't bother, I live in Florida, I don't heat.

If I was using electric heat, I would buy a Cellular switch so I can turn it on a few hours before heading to the airport. Either that or I would have a climate controlled, heated hangar and maintain the temp well above the dew point.

 

[Tom-D]

yeah, you have to go out the top. What is needed is a breather input down low so it can suck in cold, dry air.

Where is the crank case vent line located?