What's the truth about ground running?

[DXB]

9 minutes ago, larryb said:

If you have condensation inside your hanger try a fan running continuously. I had some condensation infrequently. I read about this solution on beech talk. So far so good.

 

I have a  condensation problem in my hangar.  Crappy asphalt floor that's wet after rain, then evaporates into trapped air in the hangar during warmth of the day, condenses onto the plane with cooling at night.  No venting mechanism at all. Cheap steel tools on my shelves rust rapidly.   Do you vent the fan to the outside?  Seems like you've gotta get the moist air out somehow during the day so air in hangar is no wetter than ambient humidity outside.   

[larryb]

The fan is not vented but the hanger is not air tight. Keeping the air stirred up seems to be the key.

[N601RX]

I had an issue a couple of years ago while installing a 201 windshield and 1 pc belly that I could not fly for about 2 months.  I found that a 1200 RPM idle on the ground that my engine oil temp would reach 200 deg in about 10-12 minutes.  The cylinder temps would stay around 350.  I would let it run like this for 30 minutes after the oil reached 200 deg.  I have the Centri-Lub cam so cam oiling at low speed wasn't an issue.  I have a JPI 900 engine monitor and didn't see anything that would otherwise cause concern while doing this. I did it a couple of times until the work was finished.

[M20F]

46 minutes ago, N601RX said:

I had an issue a couple of years ago while installing a 201 windshield and 1 pc belly that I could not fly for about 2 months.  I found that a 1200 RPM idle on the ground that my engine oil temp would reach 200 deg in about 10-12 minutes.  The cylinder temps would stay around 350.  I would let it run like this for 30 minutes after the oil reached 200 deg.  I have the Centri-Lub cam so cam oiling at low speed wasn't an issue.  I have a JPI 900 engine monitor and didn't see anything that would otherwise cause concern while doing this. I did it a couple of times until the work was finished.

It would have been a lot easier and cheaper to just pickle the engine or changing the oil in prior to work with just a quick start to circulate it around.

http://www.lycoming.com/Portals/0/techpublications/serviceletters/SL%20L180B%20(11-13-2001)/Engine%20Preservation%20for%20Active%20and%20Stored%20Aircraft.pdf

The cause of corrosion is the stuff in the oil.  If that stuff isn't present because the engine has been preserved or has fresh oil you aren't going to have a corrosion issue.  Calendar frequency of oil changes to me is what stops corrosion more than additives or every X hours of operation.  Better to fly oil 100hrs in a month and change then fly 25hrs in six months and change. 

[Shadrach]

3 hours ago, pinerunner said:

The issue is this. Do you really recoat the camshaft with oil if you just idle it? What I've read from Deakins and Bush is that there is only "windage" getting oil onto the camshaft lobes during regular usage. That's an oily fog inside the engine when its running that gets a little oil on everything. It's why a little blow-by turns into oil on your belly coming out the vent. No little holes pumping oil onto the lobes.

A good oil with the right additives leaves a very thin film that sticks to the cam lobes even after most of the oil has drained slowly off and if you let it sit a long time that's all you have on first startup. Just turning it over by hand will wipe that off and undo that protection without generating any windage to get a new layer on so the "turn it by hand" routine may be OK for everything except the camshaft lobes. Running it at idle presumably doesn't generate good enough windage to oil the camshaft lobes well. I suppose it does generate some windage but is it enough? Lycomings have their camshaft on the top so it might be expected to be the last thing to get windage oil on it. Running it up to speed without flying gives poor cooling. So the best advice as far as I can tell is to either fly it frequently or pickle it properly and leave it alone.

Its hard to prove these things since the camshaft is hard to get at and examine. Who's going to run it in different ways and then open it up to check the camshaft?  

There's the closed throttle idle setting (~450-500rpm IIRC) and there's where you chose to ground run an engine. I almost always run my engine at  run at 1000RPM or more for the very reason mentioned above. The cam is splash lubed by the crank and I've been told anything under about 900 RPM provides little to know oil to the cam.  The only time my throttle is closed is on approach and landing roll out.

[N601RX]

1 hour ago, M20F said:

It would have been a lot easier and cheaper to just pickle the engine or changing the oil in prior to work with just a quick start to circulate it around.

http://www.lycoming.com/Portals/0/techpublications/serviceletters/SL%20L180B%20(11-13-2001)/Engine%20Preservation%20for%20Active%20and%20Stored%20Aircraft.pdf

The cause of corrosion is the stuff in the oil.  If that stuff isn't present because the engine has been preserved or has fresh oil you aren't going to have a corrosion issue.  Calendar frequency of oil changes to me is what stops corrosion more than additives or every X hours of operation.  Better to fly oil 100hrs in a month and change then fly 25hrs in six months and change. 

So how is pickling cheaper or easier than burning 3 gallons of fuel?  The problem is these windows in not flying are not always planned, they just creep up. You are often 3 weeks in before you realize it may be a few more weeks.  Work takes longer than expected, weather bad, work, family ect.

The kits I've saw to pickle cost around $200 and will take at least a few hours.  Then you will have to unpickle and put in new oil and filter, another hr or two labor. Total close to $300 in supplies and another 4-5hrs in labor.

[pinerunner]

1 hour ago, M20F said:

It would have been a lot easier and cheaper to just pickle the engine or changing the oil in prior to work with just a quick start to circulate it around.

http://www.lycoming.com/Portals/0/techpublications/serviceletters/SL%20L180B%20(11-13-2001)/Engine%20Preservation%20for%20Active%20and%20Stored%20Aircraft.pdf

The cause of corrosion is the stuff in the oil.  If that stuff isn't present because the engine has been preserved or has fresh oil you aren't going to have a corrosion issue.  Calendar frequency of oil changes to me is what stops corrosion more than additives or every X hours of operation.  Better to fly oil 100hrs in a month and change then fly 25hrs in six months and change. 

Fresh oil just before putting it away is an excellent piece of common sense that maybe needs to be more common. Unfortunately one winter I thought I was going to fly it one more time and then had a month of bad weather. So it sat with old oil.

[Parker_Woodruff]

Go get a CFI and do some instrument approaches once a week. nothing wrong with being better than just instrument current.

Solves the moisture problem, the engine rust problem, and the rusty IFR pilot problem.

[M20F]

3 hours ago, N601RX said:

The problem is these windows in not flying are not always planned, they just creep up.

Sorry I should have been a bit clearer.  If as in your example you know you are going down for awhile, change the oil or pickle.  If the plane is flyable then find time to fly it around the pattern.  If you have time to make  it out and ground run it, then as others have pointed out for an additional 60 minutes you can burn the gunk off.

End of the day in my opinion clean oil or flying a lot are the two things that stop corrosion, everything else in my book is iffy at best.

[Andy95W]

18 hours ago, jetdriven said:

I can't remember the last time I saw a bad cam in a boat or car.  And I can't remember a week that goes by I don't hear of a lycoming with a bad one.  

 

17 hours ago, teejayevans said:

My mechanic has a 78J with original engine, 37 years in south Florida, his cam is still good. Hangared of course and replaces oil after 25 hours.

As we've discussed in other threads, rust doesn't seem to be NEARLY as big a problem as bad metallurgy- especially in the last 15 years of Lycoming camshaft production.

I think Clarence mentioned he has a couple of old cams sitting around in his shop for the past decade with no oil on them that have yet to develop rust.

[jetdriven]

9 hours ago, N601RX said:

So how is pickling cheaper or easier than burning 3 gallons of fuel?  The problem is these windows in not flying are not always planned, they just creep up. You are often 3 weeks in before you realize it may be a few more weeks.  Work takes longer than expected, weather bad, work, family ect.

The kits I've saw to pickle cost around $200 and will take at least a few hours.  Then you will have to unpickle and put in new oil and filter, another hr or two labor. Total close to $300 in supplies and another 4-5hrs in labor.

An engine dehydrator stops rust from occuring until you fly it again. There is the issue of scuffing from dry starts if it sits for weeks between flights but that seems a distant second or third to rust and cam/lifter spalling.

I bought a Tanis engine dehydrator and modified it with a humidity sensor which switches off the fan when humidity is below 20%. It lasts about 2 weeks between rechargings.

around 150$ for the Tanis, 45$ for the orange dessicant beads, and 25$ for the humidity switch/display.

 

 

[jetdriven]

On 12/21/2015 at 11:15 PM, Piloto said:

Woow!! Texas is much more humid than Florida. In 30 years in a hangar in Florida I have never seen condensation inside the hangar. Maybe your roof is leaking.

José

I know the roof is not leaking, and the hangar sits on a slab.  It hadnt rained in days.  Now imagine my surprise when I come to the hangar to go fly at 8am and the engine and prop are covered in water.  So was the sides and the roof. This is CLH's plane, but mine is the same..

[carusoam]

Observation....

Went to the hangar today...

raining outside. Cold inside the hangar from the evening before. And light moisture coat on the outside surface of the plane.

Not quite as much as Byron's picture.  JPI indicated 54°F CHTs...

Best regards,

-a-

[Piloto]

31 minutes ago, jetdriven said:

I know the roof is not leaking, and the hangar sits on a slab.  It hadnt rained in days.  Now imagine my surprise when I come to the hangar to go fly at 8am and the engine and prop are covered in water.  So was the sides and the roof. This is CLH's plane, but mine is the same..

Never seen this in my hangar. This could be caused by a sudden high temp drop at night and poor sealing of the hangar doors. Mine has rubber seals all around. Overnight temps drop here in Florida are not as high as in Texas.

José  

[bonal]

We have been having quite a bit of rain and 100% humid days for a while and today we had our first decent sky so off to the airport it was about 40 degrees but our nights have been in the 20s things were nice and dry. Took Snoopy out for a little stretch practiced some slow flight turns etc. got some more bad weather on the way so did not want to miss the chance to keep my engine happy.

[cnoe]

31 minutes ago, jetdriven said: I know the roof is not leaking, and the hangar sits on a slab.  It hadnt rained in days.  Now imagine my surprise when I come to the hangar to go fly at 8am and the engine and prop are covered in water.  So was the sides and the roof. This is CLH's plane, but mine is the same..

Never seen this in my hangar. This could be caused by a sudden high temp drop at night and poor sealing of the hangar doors. Mine has rubber seals all around. Overnight temps drop here in Florida are not as high as in Texas.

José  

We don't have rubber seals on our hangar doors here in texas. We're lucky if the doors have wheels that actually roll. I would love to have a more modern hangar but I was on a waiting list for over 2 years just to get the one I'm in, and with the current state of aviation nobody's building any new ones.

At 13 miles from the coast with a good roof vent I don't see the condensation shown above but on a cool humid morning the skins will sometimes be moist. Bi-annual corrosion-x, camguard, and weekly flights seem to keep everything in working order.

Sent from my iPad using Tapatalk

[pinerunner]

On ‎12‎/‎22‎/‎2015 at 0:09 PM, N601RX said:

I had an issue a couple of years ago while installing a 201 windshield and 1 pc belly that I could not fly for about 2 months.  I found that a 1200 RPM idle on the ground that my engine oil temp would reach 200 deg in about 10-12 minutes.  The cylinder temps would stay around 350.  I would let it run like this for 30 minutes after the oil reached 200 deg.  I have the Centri-Lub cam so cam oiling at low speed wasn't an issue.  I have a JPI 900 engine monitor and didn't see anything that would otherwise cause concern while doing this. I did it a couple of times until the work was finished.

This is the first I'd heard of Centri-Lub cams so I went to their web-site. It's an STC'd modification to the camshaft that apparently delivers oil right where you want it on the camshaft lobes right away after start up. You've got my attention and I want to know more. I think this might deserve a thread of its own. Anyone else with Centri-Lube cam? Any bad experiences? Metal to metal contact on moving surfaces in an engine should never happen. 

Here the link. Makes good reading.

http://thenewfirewallforward.com/linked/centri_lube_info.pdf

[PTK]

My opinion is that the centrilube cam may help a tiny bit on startup. It will certainly not help at all in a sitting, unflown engine. 

For my mo(o)ney! a very high quality oil such as Aeroshell 15W50 (or the AS monogrades Plus designations) or similar such as Exxon Elite changed every 25-30 hours and fly the thing.

 

[Mooneymite]

These discussions about corrosion come up from time to time and a lot of good points are made.  Corrosion is an undeniable enemy of things mechanical.

However, I am in the "skeptics corner" when it comes to some of the posts about how an engine is corroded if one doesn't fly his plane every day, week, month (pick one).

I keep my airplane in a metal hangar and I do get some condensation inside when the weather is wet.  However, in addition to my planes I also store pieces and parts that have accumulated over the years.

Here is a picture of an engine part that has sat out on an open shelf near my planes for about 12 years.  I was going to post the picture of the camshaft from an A-65 that sat right beside it (also corrosion free), but my neighbor who gives the A&P practical tests has borrowed it.  12 years with no lubrication, no nuthin' and no corrosion.

I believe corrosion is somewhat like cancer, there's no real good way to predict when, or if it will strike a particular metal part, but there are "risk factors".  Keeping your airplane in a hangar is pretty basic.

[M20F]

Good article on corrosion in particular how humidity plays a role in corrosion.  A hanger doesn't change the humidity content of air.

http://www.aviationpros.com/article/10387461/corrosion-how-does-it-affect-the-internal-engine

[N601RX]

42 minutes ago, pinerunner said:

This is the first I'd heard of Centri-Lub cams so I went to their web-site. It's an STC'd modification to the camshaft that apparently delivers oil right where you want it on the camshaft lobes right away after start up. You've got my attention and I want to know more. I think this might deserve a thread of its own. Anyone else with Centri-Lube cam? Any bad experiences? Metal to metal contact on moving surfaces in an engine should never happen. 

I overhauled my engine a few years ago with the help of an friend who is an IA. I looked at both the Ney Nozzels and the Centri-lub mod. I did several "extra's" such the centrilub and complete dynamic balance. There were several people who had cam failures and I chose to do the Centrilub in hopes it would give the cam a better chance of having a long life.  I believe Scott did it on his recent overhaul also.  

[bonal]

Why not just take a couple of electric blankets set on low and cover the prop and cowling and plug them into a timer or a remote switch device.

[Mooneymite]

48 minutes ago, bonal said:

Why not just take a couple of electric blankets set on low and cover the prop and cowling and plug them into a timer or a remote switch device.

From the above link:

http://thenewfirewallforward.com/linked/centri_lube_info.pdf

>>> Buldoc, the engine rebuilder, also strongly recommends not leaving any engine preheater on for lengthy periods, i.e. days or weeks. Clearly warm air holds more moisture than cold air. <<<

 

[bonal]

37 minutes ago, Mooneymite said:

From the above link:

http://thenewfirewallforward.com/linked/centri_lube_info.pdf

>>> Buldoc, the engine rebuilder, also strongly recommends not leaving any engine preheater on for lengthy periods, i.e. days or weeks. Clearly warm air holds more moisture than cold air. <<<

 

Asked and answered. But I did stipulate that they would be set on a timer or better yet with a remote switch one of those fancy new fangled ones you can operate with your smart phone. 

[pinerunner]

21 hours ago, M20F said:

Good article on corrosion in particular how humidity plays a role in corrosion.  A hanger doesn't change the humidity content of air.

http://www.aviationpros.com/article/10387461/corrosion-how-does-it-affect-the-internal-engine

Helpful article. Thanks.