Steps to Minimise Engine Damage after Long Downtime

[zuutroy]

I have a J with an IO-360-A36BD. 1000 SMOH with 76+ compressions when I left it for annual. However the annual has dragged for months and months due to a variety of issues. Not sure what steps the engineer has taken to keep the engine dry but as a worst case assume nothing special. It's been in a warm hangar the whole time but the climate here is humid maritime. Last flight before the downtime was pretty long so should have burned off a lot of water vapor. I should be getting her back soon and I want to know what I can do (if anything) to minimise the risks of corrosion induced shortening of engine life time. How likely is it that I've lost a few hundred hour of healthy running? Will definitely start using Camguard but I'm not sure if that can do anything after the fact, and have also been told to change the oil after about 10 hours. If the cam is spalled is it worth just IRAN parts at 1000 hours or would a full overhaul be more sensible, even though I can't afford it! Any other tips welcome.

[N231BN]

How many months? You shouldn't have any issues.

[INA201]

11 minutes ago, N231BN said:

How many months? You shouldn't have any issues.

I concur.  Mine sat for a few months during an avionics upgrade. I flew it twenty hours then switched to Cam Guard and Phillips.  You just gotta do your best when you can. Unfortunate sitting events are going to occur periodically throughout a planes life.  There are a lot of planes that sit forever all over the place which I think skews the stats and increases a true caretaker’s fear of certain failures.  

[zuutroy]

10 month in total. I guess I'm scared because I've read a lot of horror stories, but it's only the people who had problems that post about. Fingers crossed! Thanks. 

[carusoam]

You can talk about what could have been done... preservation.see what would have been protected by sealing which surfaces with preservative oil...

or cover the next steps.... pre-oil all the dry surfaces before start-up.

There May be a procedure for that somewhere.  Look where to find this, if available... Lycoming?

It may include removing plugs, inspecting cylinders, misting with oil, and pressurizing oil through the oil gallery as if the oil gear pump was operating....

It is possible to see a couple of cam lobes and lifters by removing a cylinder if this makes sense. But the damage, if it is there, has been done already....

This is PP speculation at best. Not a mechanic.

Best regards,

-a-

[jetdriven]

The most important and most highly loaded parts are the lifter faces and cam lobes. No way to pre-oil them.  only thing to do is fly it and hope for the best. A plug-in engine dehumidifier is worth the money. No water,  no corrosion.

[PT20J]

Lycoming Service Letter L180B covers this. The engines that really rust out are the ones that live in high humidity regions and are operated infrequently over a period of years. I can't see one period of inactivity killing it. Think about automobile disk brake rotors. A few weeks of inactivity in high humidity and you'll definitely notice the rust the first time you apply the brakes. But the corrosion is on the surface and comes right off after a stop or two. You have to let them sit a long time to have them actually pit. And, the rotors didn't start out being coated with oil like the engine parts.

Of course, if you had known that the annual would take so long, you would have done something differently. But, that's hindsight and you can't do anything about that. Just get it going as soon as possible and fly it often.

[GDGR]

I just became the owner of a 74 M20F. It hadn’t flown 20 hours since January of 2011. 

Opened the engine (730 Hours), and it was pristine. 

AME had the theory that running the engine for the sake of getting oil flow is just introducing moisture to the engine. 

I’d have to agree on that. Granted, I live in a fairly dry climate as well, so corrosion isn’t much of an issue. 

[Culver LFA]

I’ve been doing a little experiment at my hangar, I have a Lycoming camshaft that came out of an engine last run July 4 2017. It’s sitting on my workbench with the same oil film it had when removed, so far there is not a spot of rust on it.

[jetdriven]

Its not the camshaft so much as the lifter faces. The cam is hardened steel, however the lifters are chilled cast iron. All the photos of these spalled engines,  its always the spalled lifters running on a no-so-bad looking cam lobe. Often, the lifter is in the beginning stages of spalling while the cam lobe is still serviceable.
A lot more about this is being written over on Beechtalk. They accept the fact that "fly it often" isnt enough, and even "pour camguard and dont worry" isnt enough either. Many pilots there will pull lifters for a pre-buy or after a fishy iron reading on the oil analysis. They often catch the beginning stages of lifter face spalling and are able to save the engine. Of course, our Lycoming engine lifters (except the -76 series) cannot be removed without splitting the case, so it doesnt help us.  I did pull a couple lifters out of a IO-550 in a 2002 M20R while they had the cylinder off. Both showed early signs of failure. One has parallel scratching and the other had very slight pitting and worm trails. Cam was perfect.
Its almost always the lifters first.

Edited December 16, 2018 by jetdriven

[jaylw314]

2 hours ago, zuutroy said:

I have a J with an IO-360-A36BD. 1000 SMOH with 76+ compressions when I left it for annual. However the annual has dragged for months and months due to a variety of issues. Not sure what steps the engineer has taken to keep the engine dry but as a worst case assume nothing special. It's been in a warm hangar the whole time but the climate here is humid maritime. Last flight before the downtime was pretty long so should have burned off a lot of water vapor. I should be getting her back soon and I want to know what I can do (if anything) to minimise the risks of corrosion induced shortening of engine life time. How likely is it that I've lost a few hundred hour of healthy running? Will definitely start using Camguard but I'm not sure if that can do anything after the fact, and have also been told to change the oil after about 10 hours. If the cam is spalled is it worth just IRAN parts at 1000 hours or would a full overhaul be more sensible, even though I can't afford it! Any other tips welcome.

I'd agree with most people that one period of several months inactivity is probably not terrible, especially since it was being flown regularly prior to that.  Were you doing oil analyses?  it would be good to do those with every oil change so you can see any trends.  I imagine the first one after the long hiatus will have more iron and corrosion signs, but you'd want to see that improve over the next couple changes.

I know this is not helpful now, but in the future, ask your mechanic to "pickle" the motor if the plane is under extended maintenance.  When I had to install a new prop, and had delays, I was about to ask my shop to do so around the 4 month mark when the new prop finally got delievered.  It's a relatively quick and inexpensive process.

[Culver LFA]

24 minutes ago, jetdriven said:

Its not the camshaft so much as the lifter faces. The cam is hardened steel, however the lifters are chilled cast iron. All the photos of these spalled engines,  its always the spalled lifters running on a no-so-bad looking cam lobe. Often, the lifter is in the beginning stages of spalling while the cam lobe is still serviceable.
A lot more about this is being written over on Beechtalk. They accept the fact that "fly it often" isnt enough, and even "pour camguard and dont worry" isnt enough either. Many pilots there will pull lifters for a pre-buy or after a fishy iron reading on the oil analysis. They often catch the beginning stages of lifter face spalling and are able to save the engine. Of course, our Lycoming engine lifters (except the -76 series) cannot be removed without splitting the case, so it doesnt help us.  I did pull a couple lifters out of a IO-550 in a 2002 M20R while they had the cylinder off. Both showed early signs of failure. One has parallel scratching and the other had very slight pitting and worm trails. Cam was perfect.
Its almost always the lifters first.

I should have mentioned that the hardening is long gone on this camshaft. Plus only the lobes and bearing journals would have been treated, not the entire shaft.

The tappets are on the bench with it, I’ll check them closely tomorrow.

Edited December 16, 2018 by Culver LFA

[mike_elliott]

54 minutes ago, Culver LFA said:

I’ve been doing a little experiment at my hangar, I have a Lycoming camshaft that came out of an engine last run July 4 2017. It’s sitting on my workbench with the same oil film it had when removed, so far there is not a spot of rust on it.

In 2011 I pitched away a camshaft from a Datsun race car I owned. It had been sitting in a dirt floor shed for over 35 years. No corrosion at all on the lobes. Granted it was in Indiana, but it gets pretty humid there in the summer fall and spring. I am not completely buying in that corrosion is the culprit of the Lycoming cam/lifter spalling issue. Perhaps a metallurgy test of hardness might reveal more....

[Cyril Gibb]

If the concern is about the lack of "splash" lubrication on the cam and lifter faces at startup, how about filling the crankcase with oil to submerge the cam and lifters.  Drain back to 6 quarts and save he drained oil for the next few oil changes.

[jetdriven]

be sure to un-hydrolock the cylinders before starting it

 

[Cyril Gibb]

3 minutes ago, jetdriven said:

be sure to un-hydrolock the cylinders before starting it

I hadn't thought of that, but would there be much chance of oil seeping past the piston/oil control ring/compression rings for just a few minutes at essentially zero pressure?

[PT20J]

1 hour ago, jetdriven said:

Its not the camshaft so much as the lifter faces. 

That's what I've always heard from guys that have torn down a lot of engines.

[INA201]

What do you guys think about preheating thoroughly so the oil quickly flows to all the parts, especially after extended sitting?   I preheat as a normal rule below 40.

[jetdriven]

25 minutes ago, Cyril Gibb said:

I hadn't thought of that, but would there be much chance of oil seeping past the piston/oil control ring/compression rings for just a few minutes at essentially zero pressure?

The same reason a radial engine hydrolocks after a fuel stop. Theres no way to guarantee it wont, and it trashes the engine if it does.

[PT20J]

The cylinders of a radial engine are arranged in a vertical plane and gravity causes oil to flow down to the bottom cylinders after shutdown. It can get past the rings, but mostly it fills up the lower rocker boxes and seeps into the cylinders through the valve guides. The starters on radials have a friction clutch that's supposed to slip before any damage is done, but we never trust it and always pull the props through a couple of engine revolutions before starting if it's been sitting a while. Also, when you observe someone starting a radial, you might notice the prop turning a long time before it starts. That's because we count 12 blades before turning on the mags -- just to be sure. 

It's unlikely that a horizontally opposed engine would have a hydraulic lock from just sitting around. However, if an engine is preserved using Lycoming's procedure in SL 180B, you will have added 2 oz. of preservative to each cylinder and this could certainly cause a problem if it were not removed.

If the engine has been sitting a long time, it might be a good idea to pre-oil it as Lycoming recommends before starting a new, overhauled or rebuilt engine. This can be done by removing the spark plugs and spinning the prop either by hand or with the starter until oil pressure is indicated. This will also ensure that there is no chance of a hydraulic lock.

Skip

[thinwing]

I wonder how completely filling engine with cheapest reclaimed moter oil to top of filler neck completely submerging cam ,lifters cyl etc would work?Interesting idea...regardless ,I'm interested in what turned an annual inspection into a 10 month project...

[Guest]

While establishing oil pressure on a dormant engine is a good idea prior to starting it, I’m not sure cranking it with the starter motor is a great plan.

A simple pressure pot connected to the front right gallery plug of a Lycoming engine works fine.  In the shop we have a 1 gallon pressure pot for this job. For a one time use for an owner a 1 gallon plastic weed sprayer and a short piece of hose connected to the same plug with a few fittings should get the job done.

I once filled an IO-360 crankcase with oil for a customer with a dormant engine.  It worked fine other than taking a huge amount of oil(still cheaper than a camshaft)  and it cost a pair of magneto repairs.  The seals on a magneto aren’t meant to hold back that quantity of oil.  Both mags filled up and started leaking.

Clarence 

[zuutroy]

13 hours ago, thinwing said:

I wonder how completely filling engine with cheapest reclaimed moter oil to top of filler neck completely submerging cam ,lifters cyl etc would work?Interesting idea...regardless ,I'm interested in what turned an annual inspection into a 10 month project...

Corroded flight control pushrods and a few other parts needed replacing. They were initially sent over without 8130-3 which we have to have here. They were sent back and re-issued. That whole process went on for months. Since October all I know he's waiting on 'a part'. It's my first annual, and he's not an easy guy to get hold of, but I'm told by another customer that he wants it out of his hangar asap. 17 months of airplane ownership and I've had it less than half that time 

Edited December 18, 2018 by zuutroy

[Raptor05121]

On 12/16/2018 at 3:21 PM, zuutroy said:

10 month in total. I guess I'm scared because I've read a lot of horror stories, but it's only the people who had problems that post about. Fingers crossed! Thanks. 

My plane had a 10 month annual from Oct 2015- Nov 2016 with 0 hours running. Got it back, flew 50 hours in a month. Oil samples were clean.

I wouldn't worry about it, personally. (I'm at 2200SMOH)

[PT20J]

8 hours ago, zuutroy said:

It's my first annual, and he's not an easy guy to get hold of, but I'm told by another customer that he wants it out of his hangar asap. 17 months of airplane ownership and I've had it less than half that time 

The first annual is usually painful, in my experience. You get to find all the little things that the previous owner deferred, and they add up. Sounds like this annual was pretty thorough, so next year it should be much better. Hang in there and think of all the fun you’ll have when you get it out of the shop.