Engine hasn't run in a while. What to do?

[PTK]

Between work and the lousy weather, my plane hasn't been started in so long I'm beginning to worry about it. I've read that doing a ground run won't get the engine hot enough to do any good, but is it better than letting an engine sit for weeks without being run at all? I'm tempted to go down to the hangar, pull the plane out and run it for 15 minutes or so to get the oil back on all the stuff that could rust, and charge up the battery a bit.

Obviously, the best thing to do would be to go fly, but I don't know when that will be.

Jamie, if you take the time to go to the airport you should try and spend a little more than 15 minutes and actually take a few spins around the pattern.

As others have suggested, take an instructor with you if under the wx.

Anything short of flying your engine are just creative "feel good" excuses to relieve the guilt of not flying.

You aren't doing your engine any favors by not flying it.

If you just can't fly it for the longer term, instead of ground running it, you should consider preserving it with Aeroshell Fluid 2F or something comparable:

http://www.shell.com/global/products-services/solutions-for-businesses/aviation/products/lubricants/fluids-and-preservatives/2f.html

[orionflt]

The cam is only lubricated by splash oil which is why 1000rpms is recommended by alot of maintenance shops immediately after start up as opposed to idling at the slowest possible speed after start. Hand cranking wonnt lubricator the cam or lifter faces.

The main issue as we all know is cam issues, so this still doesn't do anything to help these components. I'd speculate it might actually do more harm because when the engine is turned over the dry liftes against the cam scrape off any rust and then grinds and leaves another shinny surface for the rust to further eat into.

Sitting is a bad deal all the way around.....nice to see so many people putting a lot of thought into this topic though.

You are correct that the engine uses splash oil to lubricate parts of the engine and 1000 rpms is recommended for warm up (most efficient engine speed to get the oil up to temp with the least amount of wear on the engine), but believe me, hand propping the engine with plugs removed will splash enough oil thru out the engine to coat the cam tappets and piston pins. That is unless your trying to do it in the middle of winter when the oil is so thick it won't flow (hence preheating). Pre oiling (that is what you are doing) is used prior to starting an engine when it is put into service and is recommended to help reduce wear during normal starts. Look up pre oilers, there are a number of companies selling electric oil pumps just for that purpose. Oh by the way, cam guard is great because it helps keep the engine parts coated when youdo not fly regularly, but leave the engine sit too long with out preserving it even with cam guard and you will have the same problems.

Brian

A&P IA

[Jamie]

Looks like the weather might FINALLY be changing toward the end of this week. If not, I'll find an instructor and get it off the ground that way.

 

I sort of knew about the need to regularly fly before I bought the plane, but I didn't think it'd be like this. If I wanted a dependent I would have bought a dog.

[jetdriven]

You are correct that the engine uses splash oil to lubricate parts of the engine and 1000 rpms is recommended for warm up (most efficient engine speed to get the oil up to temp with the least amount of wear on the engine), but believe me, hand propping the engine with plugs removed will splash enough oil thru out the engine to coat the cam tappets and piston pins. That is unless your trying to do it in the middle of winter when the oil is so thick it won't flow (hence preheating). Pre oiling (that is what you are doing) is used prior to starting an engine when it is put into service and is recommended to help reduce wear during normal starts. Look up pre oilers, there are a number of companies selling electric oil pumps just for that purpose. Oh by the way, cam guard is great because it helps keep the engine parts coated when youdo not fly regularly, but leave the engine sit too long with out preserving it even with cam guard and you will have the same problems.

Brian

A&P IA

How does turning the prop by hand get enough oil on the cam? It takes 1000 RPM or more to splash enough oil on it. I wouldn't move the prop unless I was going to run the engine.

[aaronk25]

I want to know to????????

[orionflt]

How does turning the prop by hand get enough oil on the cam? It takes 1000 RPM or more to splash enough oil on it. I wouldn't move the prop unless I was going to run the engine.

It doesn't take1000 rpms to splash oil on the cam, your normal engine idle is between 600-650, 1000 rpm is the most efficient for engine warm up not lubrication. As for your last comment about not moving the prop unless your going to start the engine, do you pull the prop thru prior to starts to ensure you do not have a dead cylinder? That is a recommended preflight procedure and you are defiantly not splashing oil on the cam when you do that. There is always going to be some wear on moving parts the parts were designed to take this, the worst thing we can do to our engines is to let them sit. Ideally flying the plane and bringing the engine up to temp is the best solution but the key to protecting the engine is to keep those parts coated with oil.

[jetdriven]

It doesn't take1000 rpms to splash oil on the cam, your normal engine idle is between 600-650, 1000 rpm is the most efficient for engine warm up not lubrication. As for your last comment about not moving the prop unless your going to start the engine, do you pull the prop thru prior to starts to ensure you do not have a dead cylinder? That is a recommended preflight procedure and you are defiantly not splashing oil on the cam when you do that. There is always going to be some wear on moving parts the parts were designed to take this, the worst thing we can do to our engines is to let them sit. Ideally flying the plane and bringing the engine up to temp is the best solution but the key to protecting the engine is to keep those parts coated with oil.

 

My normal engine idle is 650 RPM, but it never spends time at that speed. Its always 1000-1200 RPM on the ground, occasionally 800 if taxiing downhill.

 

I dont pull the prop through before starting.  I'll take my chances on the dead cylinder but it gets a compression test every hundred hours and its all 78s. Its monitored by a multi-point engine monitor and it shakes pretty evenly at startup and shutdown.  I dont think pulling the prop through would harm mine as it has a roller camshaft. That doesn't prevent cylinder wear however.

 

Here is a picture of a Lycoming wide deck crankcase.

The oil sump is below the case halves, and that is separated by the bottom of the case which has a few very narrow openings for the oil to drain through.  The camshaft depends on windage from the rotating crank and the oil from the piston cooling jets deflected from the bottom of the piston skirts. I simply cannot think how 30-50 RPM is going to throw oil onto the cam. It takes the several quarts per minute of oil coming from the oil pump, escaping the bearings in the crank to create that kind of windage.

 

Lycoming SL180B says not to pull the prop through as it wipes the oil off the cam, and then starting the engine with a dry cam causes damage. 

 

ECI says that RPM must be 1800 to lessen the cam lobe stress for initial run in, and that low RPM also increases cam stress.   www.eci.aero/pdf/breakininstructions.pdf‎

[aaronk25]

My normal engine idle is 650 RPM, but it never spends time at that speed. Its always 1000-1200 RPM on the ground, occasionally 800 if taxiing downhill.

 

I agree I do the same, and ride the brakes some if necessary, which most of the time it is.  Brakes are cheap compared to even a slight bit more engine wear.  The 650 idle is critical though for maximizing short field landings, but even on power off the windmill propeller keeps the RPMs in the good zone.  

[jetdriven]

With a roller cam engine I dont think there is a minimum idle speed limitation anymore. However, if sitting at idle more than a very short time, the plugs can foul. The TCP lead scavenging agent needs heat to be active and it takes ~1000 RPM to do it.

[fantom]

Hey Byron....when you're at Oshkosh if you go by the Lycoming tent, please check to see if they are still running the "super" special on a trade of a first run IO-360 engine that's less than 20 years old, on a new roller cam engine. They had very attractive pricing last year, and got me thinking....for the future.

 

Thanks!

[jetdriven]

They do, but its not the deal it seems. You get the Rebuilt engine for the Overhaul price. Its the same unit except the Rebuilt has a 2 year warranty and a zero time logbook. Its the same parts.

[fantom]

How are they rebulding roller tappet engines so quickly?

[jetdriven]

They arent.  We got a new case because they dont have roller cam cores. All engines come with new cylinders, pistons, valves, etc.  The only thing that likely has time on it are the crank, rods, oil sump, camshaft, and all the accessory gears etc.  And the data plate, which is a new stamping with an old serial number.

[fantom]

OK...makes sense to me now. Thanks!