O320 how prevalent are cam issues when sitting

[alaskan9974]

Bought a flight school 172, motor is 300snew installed in 2013, but sat for a few years, ground run in annual but no more time then that.

Pulled valve covers some rust on springs but nothing crazy, I scoped acc case gears after I got the mags off, light surface but no pitting.

My IA said run it and if it makes metal in 100hr I can split it and he can rebuild with a new cam and lifters. I typically do oil and filter changes every 25 hours and typically fly 50~ per month.

What’s the risk to the engine when the lifters start to wear, am I looking at damage to the main bearings and case?

 

[Stewartb]

It’s a crapshoot. Some 320 cams rust and pit even when used regularly. Some look great after years of minimal use. If in doubt? Pull a cylinder and look at the cam.

 

[mondtster]

What’s the risk to the engine when the lifters start to wear, am I looking at damage to the main bearings and case?

The risk is that metal will end up everywhere when the cam goes, and you'll need to get it out. There will almost certainly be metal that ends up in the crank and rod bearings, which should be replaced. I've never had a case that couldn't be reused after a cam failure.

Generally speaking, the older cams and lifters (1990ish and earlier) seem to fare better with intermittent use than more recent ones do. That has been my observation based on the engines I've overhauled anyway.

 

[Dan Thomas]

Generally speaking, the older cams and lifters (1990ish and earlier) seem to fare better with intermittent use than more recent ones do. That has been my observation based on the engines I've overhauled anyway.

I always wanted to know how many times that engine had been ground-run and put away without it being flown. That there is what causes corrosion, lots of it. And that's the one factor that is left out of most conversations like this.

Pull the airplane out, start it up and run it for ten minutes, then shut it down and pull the rocker covers off. It's shocking how much moisture you find in there, and it's not from the environment. Burning fossil fuels creates water vapor, more than a gallon of liquid water for a gallon of fuel, and some of that gets past the rings in a cold engine, with its larger clearances, and condenses in the case, and only flying the thing for some time will get it out again.

 

[Magman]

A Cherokee was hangared up on jacks for when ( not if) the nearby river overflowed.

It had been that way for 25 years!

Pulling all cylinders and a thorough investigation showed zero rust.

I have seen the water Dan mentioned also.

Once was on an engine where Rocker Covers were blasted at MOH and the

engine was run in a test cell.

One week later a cover was removed and already showed rust.

FYI Metal from the Cam can take out cylinders.

Also takes out the warranty on them!!!

 

[bnt83]

Got a whole slew of new parts for an O320E2D engine overhaul, meanwhile the 53 year old engine soldiers on. 3 out of 4 cylinders have never been off. Compressions are usually high 60 to low 70s. It does use some oil. We have owned it for 20 years or so and put around 900 hours on it in that time.

As Stewart says, it a bloody crapshoot, most everything old is.

Most bad cams don't lead to an in-flight engine failure though. There was a brand new O-320 camshaft in a Special Airworthiness bulletin that had less than 200 hours on it that looked like new, except it was completely cracked through, and it looked like the crack started where the part number was stamped into it.

 

[Domenick]

Camguard. It will cause your oil to linger a bit longer on the internal parts. It is something of a religious issue, but it certainly will not hurt.

 

[Clip4]

Bought a flight school 172, motor is 300snew installed in 2013, but sat for a few years, ground run in annual but no more time then that.

Pulled valve covers some rust on springs but nothing crazy, I scoped acc case gears after I got the mags off, light surface but no pitting.

My IA said run it and if it makes metal in 100hr I can split it and he can rebuild with a new cam and lifters. I typically do oil and filter changes every 25 hours and typically fly 50~ per month.

What’s the risk to the engine when the lifters start to wear, am I looking at damage to the main bearings and case?

Where did the plane reside?

 

[mondtster]

[

A Cherokee was hangared up on jacks for when ( not if) the nearby river overflowed.

It had been that way for 25 years!

Pulling all cylinders and a thorough investigation showed zero rust.

I have seen quite a few engines come back clean that were stored in similar conditions. One of the cleanest engines I did was on a float plane that sat on the dock all summer and was stored outdoors all winter. If we were to believe all the generally accepted theories on what makes an engine go bad, this one should have been junk.

My personal suspicion, based on the engines I've personally had apart, is that corrosion is a factor but is less of a concern than low quality parts and a lack of lube at startup is. A bit of luck is also involved.

 

[Dan Thomas]

My personal suspicion, based on the engines I've personally had apart, is that corrosion is a factor but is less of a concern than low quality parts and a lack of lube at startup is. A bit of luck is also involved.

The engines that I've found corroded internally were ground-run, and the owners admitted it. That, and the fact that I've found liquid water in engines briefly run before removing rocker covers or other components such as cylinders, tells me that the ground-running is a massive problem, one that even the engine manufacturers warn you against. Ram, the reputable engine shop, also warns against it.

Jump ahead to the 3:05 mark if you don't want to watch it all. Note that some of the pictures in that video are of parts that were not removed from an operating engine; they are corrosion test pieces, subjected to salt water. Those pics can be misleading to the uninitiated.

 

[chemgeek]

Based on my experience, when lifters start to spall, it's time to split the case. BTDT. If the lifters haven't pitted yet and the cam is not showing signs of wear, you might get lucky and be able to run the engine for quite a while. If you are not flying weekly, it would be highly recommended to use CamGuard additive to minimize corrosion during periods of inactivity. But the kindest thing to do for your engine is to run it often for at least one hour at full operating temp. (That is, FLY it.)

 

[mondtster]

The engines that I've found corroded internally were ground-run, and the owners admitted it.

I’m well aware of what happens with ground running. It is not a common occurrence for owners to do that, at least from what I’ve seen. Perhaps people in other parts of the world do it more frequently.

What is a very common occurrence here is for airplanes to sit for months or years at a time with no preservation. Cams and lifters i these engines still fail and rust doesn’t seem to be the primary factor. Hence my belief that parts quality and startup wear claims more engines than rust.

 

[Snowmass]

Bought a flight school 172, motor is 300snew installed in 2013, but sat for a few years, ground run in annual but no more time then that.

What’s the risk to the engine when the lifters start to wear, am I looking at damage to the main bearings and case?

I would not worry as much about the mains because capillary action would hold oil in the main and rod bearings but open cam surfaces are much more likely to lose an oil coating.

 

[Stewartb]

Crack open the rocker drains on pretty much any Lycoming that operated in cold weather and then cooled fully and you’ll find water.

 

[nrpetersen]

How about a small ventilating fan pressurizing the oil-add cap for a still hot engine? This would clear a lot of the water etc out the breather, but the system would have to be applied while the crankcase is still hot.

PCV (positive crankcase ventilation has been used on automobile engines for years and probably contributes substantially to the life of modern engines. They all run the crankcase fumes through the intake manifold & out the exhaust. I know has been talked about but still is not done in aircraft engines because of potential reliability problems.

 

[mondtster]

PCV (positive crankcase ventilation has been used on automobile engines for years and probably contributes substantially to the life of modern engines. They all run the crankcase fumes through the intake manifold & out the exhaust. I know has been talked about but still is not done in aircraft engines because of potential reliability problems.

I don't see how it would work very well in an aircraft engine with minimal difference between the ambient air pressure and manifold pressure in the typical cruise configuration...

Most motorcycles do not have a PCV system and I don't see the life being cut short on those engines due to the lack of it. Neither do diesels. While I do feel PCV offered a bit of life extension in certain cases, there are detriments to the system that also need to be considered. Intentionally burning oil vapor being the main one.

 

[Magman]

It won’t cure pre-existing conditions but Engine Dryers will alleviate internal

corrosion.

You can buy or make your own.

Aquarium Pump and a couple jars of desiccant will get you going.

 

[alaskan9974]

Where did the plane reside?

Alaskan Arctic. About 60 miles inland

Put a few hours on and then cut the filter, nothing to be seen yet. Will try again in 5 more hours. Was factory new in 2013 looking at the build sheet it just lists the factory lifter #

 

[scarcherpilot]

Dont know if this helps or not, but read a comment/practice on another forum that I have adopted, but when I get the plane back in the hangar after a flight, I open the oil fill cap while I am wiping down the bugs off the plane unloading it or tinkering in the hangar. His theory was it may let some of the moisture out since the engine is still hot. I figure it couldn't hurt and I always make sure to put the cap back on before I leave. Mine is a O-300 though.

 

[Omalley1537]

I don't see how it would work very well in an aircraft engine with minimal difference between the ambient air pressure and manifold pressure in the typical cruise configuration...

Most motorcycles do not have a PCV system and I don't see the life being cut short on those engines due to the lack of it. Neither do diesels. While I do feel PCV offered a bit of life extension in certain cases, there are detriments to the system that also need to be considered. Intentionally burning oil vapor being the main one.

That last part became particularly problematic when GDI became common…without the fuel washing over the intake valves, the oil vapor and other “schmutz” has been known to accumulate on them.

 

[Eric Pauley]

Does this engine have roller lifters? You can tell based on the serial number (E suffix means rollers). At least in theory having these should reduce issues with cam wear on lycoming.

 

[pfarber]

I don't see how it would work very well in an aircraft engine with minimal difference between the ambient air pressure and manifold pressure in the typical cruise configuration...

Most motorcycles do not have a PCV system and I don't see the life being cut short on those engines due to the lack of it. Neither do diesels. While I do feel PCV offered a bit of life extension in certain cases, there are detriments to the system that also need to be considered. Intentionally burning oil vapor being the main one.

You are always burning oil, thats how the system works. Passing blowby gases through the intake is a non-issue, the fuel is a natural solvent.

PCV is all about moisture. Engines now only have what cars did 70 years ago... A road tube (direct vent to atmosphere) which is not as effective as pulling the vapors out with manifold vacuum.

If a pcv system was installed it would require a new maintenance item to ensure the tube and oriface remain clear but that can be done at every oil change.

As for motorcycle engines... They dont burn nearly the same amount of fuel to create the same amount of water. And even a cycle engine is not 100% airtight, there are always ways for thr vapor to escape otherwise you would be spitting oil everywhere whe the block pressurizes with blowby gasses

The real issue is the engine manufacturers simy don't care and the FAA makes the process of any improvement way to hard.

 

[Domenick]

Chuck Ney Enterprises, Tulsa, OK had an STC for installation of a Ney Nozzle. It sprayed oil directly on the cam of a Lycoming. chuckneyent.com n ow yields a "404 Not Found" error. You should be able to find a phone number. I know Chuck died a few years back and the kids took over the biz.

There is also something called a Centri-Lube STC. Word was, if your cam is already out of the engine it was not pricey. The camshaft is drilled to force oil through the shaft and onto the lobe faces.
https://firewallforwardengines.com/stc/

 

[pfarber]

The ney nozzle can only be added when the case is split. Back in 94 the cost was $250-ish plus the cost of welding the case.

A preoiler alone is not a great solution as the rings and lifters and cam are all splash lubed unless you make mods.

I would definitely do both if i had an engine in for overhaul. The cost seems less than a grand or so

 

[mondtster]

You are always burning oil, thats how the system works. Passing blowby gases through the intake is a non-issue, the fuel is a natural solvent.

PCV is all about moisture. Engines now only have what cars did 70 years ago... A road tube (direct vent to atmosphere) which is not as effective as pulling the vapors out with manifold vacuum.

And what engine vacuum are you proposing to use? There is little to none in cruise configuration. Perhaps the idle time taxiing back to the hangar is enough to get the job done, it's hard to say.

Regarding burning oil, I know how the system works. It is a good plan to avoid burning as much oil as is practical. Why is the FAA interested in having us run Ashless oil? Same reason.

As for motorcycle engines... They dont burn nearly the same amount of fuel to create the same amount of water.

I think you're a little out of touch with motorcycle engines and their performance levels.

 

[Stewartb]

How about a small ventilating fan pressurizing the oil-add cap for a still hot engine? This would clear a lot of the water etc out the breather, but the system would have to be applied while the crankcase is still hot.

PCV (positive crankcase ventilation has been used on automobile engines for years and probably contributes substantially to the life of modern engines. They all run the crankcase fumes through the intake manifold & out the exhaust. I know has been talked about but still is not done in aircraft engines because of potential reliability problems.

Anti Splat offers a very nice crankcase vacuum kit. I put one on my Cub. Said to increase power but definitely eliminates breather drip. Lots of validation of the concept in the car racing world.

I built a couple of low volume engine dehydrators and monitored the crankcase humidity last winter. I’m absolutely positively going to use them again. I’ll start a new thread with pics, part numbers, and the results.

 

[Dan Thomas]

PCV is all about moisture. Engines now only have what cars did 70 years ago... A road tube (direct vent to atmosphere) which is not as effective as pulling the vapors out with manifold vacuum.
If a pcv system was installed it would require a new maintenance item to ensure the tube and oriface remain clear but that can be done at every oil change.
The real issue is the engine manufacturers simy don't care and the FAA makes the process of any improvement way to hard.

As has been noted MANY times here, the usual PCV system does not work with aircraft engines. It's a fact of physics, and wishful thinking or uninformed criticism won't change it.

A typical cruise MP setting is 25"Hg. The atmospheric pressure at sea level, standard day, is 29.92"Hg. You lose an inch per thousand of atmospheric pressure as you climb. If you're at 5000 feet ASL the pressure is 24.9, meaning that the throttle has to be wide open to get anywhere near that pressure in the manifold. At 3000' ASL you might get a two-inch difference in pressure, still not enough to move much air through the case. A turboed engine wouldn't work at all. Whatever suction you get while taxiing back to the hangar wouldn't effectively remove the water that has been mixed with the oil during operation. It's emulsified into it, which is why flying the airplane for at least an hour at operating temps is so importance to preventing corrosion. You have to rely on heat to raise the vapor pressure of the water to drive it out with the blowby gases.

So one either runs the engine at 50% or something to get the suction, or needs something else to generate it to purge the case. A pump? How long would any vacuum pump last with all that crud going through it? Ever seen the inside of a crankcase breather tube? Ugly. And it needs to be driven by another mounting pad on the engine, or by an electric motor. A venturi in the air intake to generate suction? There's a bunch of induction drag that has the effect of throttling the engine. The Anti-Splat system is not a true PCV system; it just encourages the gases to leave. There is no fresh-air inlet as there is with PCV. The only air entering the case is blowby stuff.

I don't know. You think it's simple, you do it and get it patented, sell it to the OEMs and make big bucks.

 

[Gary Ward]

I always wanted to know how many times that engine had been ground-run and put away without it being flown. That there is what causes corrosion, lots of it. And that's the one factor that is left out of most conversations like this.

Pull the airplane out, start it up and run it for ten minutes, then shut it down and pull the rocker covers off. It's shocking how much moisture you find in there, and it's not from the environment. Burning fossil fuels creates water vapor, more than a gallon of liquid water for a gallon of fuel, and some of that gets past the rings in a cold engine, with its larger clearances, and condenses in the case, and only flying the thing for some time will get it out again.

I am a former top alcohol dragster racer. We raced supercharged all aluminum hemi engines. WE ran the engines for a few minutes in the pits to warm them up and under power for 5 seconds on the drag strip. It might run 2 minutes on the track, no cooling system except for the methanol which helped cool the motor.. Those motors made so much water that we used new oil every run, 12 qts every run. The oil was a milky color from rich fuel during idle and water.

I bought a 172 from a friend who flew it 10 hours in 10 years. It has a 0320 H2AD motor in it.

I flew it for him as a favor at first. I did the maintenance and he let me fly it because he lost his medical. I was very worried about the motor from sitting. He said he would turn it over by hand. I don't think he started it much without flying it.

After 6 months of flying it I bought it from him. I flew it 350 hours to about 1700 hrs total time on motor since new(40 years old).
I was leaking it and keeping track of how much oil it was using. It started using more oil and the leak numbers were going down. So Xmas 2019 I pulled the lifters cause you can on a H2AD. There was some spauling on the lifter/tappets but the cam lobes looked OK.

Then I pulled all 4 clys, they looked pretty good and I could see the cam better. Cam looked good to me although it had microscopic rust pits on the lobes. Only could see them with a magnifier. I think they helped hold oil better? lol Half way joking.

The only thing I found with the clys were 3 pistons had the ring gaps lined up. Could still see some hone marks.

So decided to put it back together with the rings spaced apart while waiting for a lycoming rebuilt. I did clean up the pistons and rings and made sure they were free.
Still a little nervous about the spauling but I wanted a motor to fly with and did not want to be down for months.

The motor ran great and the oil consumption went from 1 qt per 4 hours to 1qt per 8-9 hours. I was thrilled and bummed that I ordered a replacement motor.

I ran the motor for another 100 hours by the time I had to return it.
I sent an oil sample to Blackstone when I swapped motors and they said the oil looked normal with 100 hrs on it.
I flew it to 1800 hrs and it easily would have gone to 2000 and beyond I am sure. This motor did not have the T mod done to it.
One lifter still showed the rockwell hardness test marks on it.

And some looked like this.

 

[Stewartb]

That's corrosion in the non-contact area, not spalling. Kind of interesting. The rule I was taught for cams is when you can detect pitting with a fingernail? It's toast.

 

[Stewartb]

To the PCV topic? https://antisplataero.com/products/crankcase-vacuum-kit-complete It works great in combination with their oil-air separator.
Google crankcase vacuum and you'll get tons of info, some of it really good.

 

[Dan Thomas]

To the PCV topic? https://antisplataero.com/products/crankcase-vacuum-kit-complete It works great in combination with their oil-air separator.
Google crankcase vacuum and you'll get tons of info, some of it really good.

The fact remains that it doesn't draw fresh, dry air through the crankcase as does a normal PCV system. That will limit its ability to remove water. The air in there can remain saturated. The only stuff going into the case is more blowby, consisting of water vapor and a bunch of other corrosive compounds. It would be nice to get a couple cubic feet of air per minute through the case. This thing would help but it's not the complete solution. Doesn't appear to be STCd for TCd aircraft, anyway.

 

[Stewartb]

Criticize without researching again? My oil stays remarkably clean. I’m impressed with it.

 

[alaskan9974]

Does this engine have roller lifters? You can tell based on the serial number (E suffix means rollers). At least in theory having these should reduce issues with cam wear on lycoming.

The engine number ends in -27E, is that the one you are referring to?

This is my first lycoming my other planes are all Contis where can I find more info on these lifters and how they work (differently?) and I am assuming it is better for longevity?

 

[Domenick]

The ney nozzle can only be added when the case is split. Back in 94 the cost was $250-ish plus the cost of welding the case.

A preoiler alone is not a great solution as the rings and lifters and cam are all splash lubed unless you make mods. ...

Someone, somewhere, maybe on this forum, for a plane that has been sitting, suggested pulling the top plugs, squirting a bit of oil into each cylinder, and running the starter until oil pressure comes off the peg.

Do you think that would splash enough oil onto the cam to help during the start?

 

[Jack Cabano]

Zero cam issues while sitting, and engine not running...

Occasional issues once engine starts...

 

[Snowmass]

Someone, somewhere, maybe on this forum, for a plane that has been sitting, suggested pulling the top plugs, squirting a bit of oil into each cylinder, and running the starter until oil pressure comes off the peg.

Do you think that would splash enough oil onto the cam to help during the start?

No, but there are spray devices that can create a fog of diluted oil which might be forced into the oil cap entrance and if an oily mist comes out the breather pipe then there is a good chance of an oil film on the cam. I once used a device like this to mist oil on a saw blade cut when cutting soft aluminum.

 

[Albany Tom]

I don't know how overhauls are done on aircraft engines, but on automotive engines, you use an assembly lubricant on the cam and bearings. If you don't do that, consensus is you're damaging the engine on the first start. There's no way to get that initial coating of grease/oil in there after the engine is put together. But that's worst case, with absolutely no lubrication between the metal parts. Even if an engine has been sitting for a long time, there's likely going to be some sort of lubricant left between parts.

So my wild a** guess is that the best protection is to use whatever the best oil is, if you're going to let an engine sit. I'm thinking that's an appropriately rated fixed weight oil, with camguard added because it might help.

I think my concern on an engine that has been sitting isn't a worn cam and reduced power as much as it is sticking valves. I've read more accident reports about old engines eating valves, and know someone that happened to, than people running into trouble with gradually reduced power. I could be all wrong here, though. Going on anecdotal information and memory.

 

[Stewartb]

One of Lycoming’s assembly oil recommendations is a 50/50 mix of 50wt mineral oil and STP. Works great.

 

[Gary Ward]

One of Lycoming’s assembly oil recommendations is a 50/50 mix of 50wt mineral oil and STP. Works great.

Like many here I have built and rebuilt plenty of engines.

You remind of my youth and Richard Petty when you mentioned STP . Yes motor oil and STP was the magic lube I used when I was young. I have kind of forgot about STP and have not used it in 30 years I bet. Not knocking it at all, just kind of forgot about it.

I used to rebuild racing hemis a couple a month. I had 3 of them that I would rotate them. After 12 runs they got new rods and pistons. Most times we changed engines at the track and would bring an engine home to refresh.

They got new upper rod bearings every run. I tune the engine using the upper rod bearings.

I use white grease on the rod and main bearings.
I use black moly grease on the cam and lifters.
One drop of motor oil on the piston skirts, just a drop on each side on the skirts not the rings.

Then the only thing I put on the cly walls and rings is WD40. It works great for quick and complete ring break in.

I did the same on the my lycoming 320. The used rings and cly walls were fine with WD40 . My oil consumption greatly improved after reinstalling the 40 year old used rings.

Many would think WD is not enough, try it it works great.
My 2 cents.

 

[Gary Ward]

That's corrosion in the non-contact area, not spalling. Kind of interesting. The rule I was taught for cams is when you can detect pitting with a fingernail? It's toast.

That makes sense...now that you mention it.

If it was spalling it would have ate the cam by now, right? It looks like the cam just contacts the very center of the lifter?

Another note I need to mention on this h2ad motor. According to the logs at 100 some hrs they found metal in the filter. It then got a new cam and lifters and engine overhaul. This was done shorty after the plane was new. I measured the lifters and they are not the larger lifters. I don't think the T mod was used then? I can't remember the exact hrs because I sent the old engine log back along with a good running core engine....uuuggghhhh.