Worn camshaft, some corrosion, some metal in oil

Will Kumley

Will Kumley

Line Up and Wait
Joined
Aug 6, 2019
Messages
698
Location
Pacific Southwest
Display Name
Display name:
Will
How much would this concern you on a potential purchase? Seller states he is selling the plane as his mech noticed some metal in the oil and after performing a borescope inspection noticed the camshaft had some corrosion and had some wear. States it will likely need to replaced soon. I'm admittedly dumb in this world as I usually work with go fast engines on military aircraft but am I thinking correctly that a camshaft replacement may as well be a full overhaul?
 
Will Kumley said:
How much would this concern you on a potential purchase? Seller states he is selling the plane as his mech noticed some metal in the oil and after performing a borescope inspection noticed the camshaft had some corrosion and had some wear. States it will likely need to replaced soon. I'm admittedly dumb in this world as I usually work with go fast engines on military aircraft but am I thinking correctly that a camshaft replacement may as well be a full overhaul?
Click to expand...
It could be just an IRAN, but that involves nearly as much labor so most would do an overhaul.
 
If you’re financially concerned, price in an overhaul. The corrosion may not just be limited to the cam, and disuse could have caused other maintenance related issues to not be far behind.
 
As others have stated, the only way to replace the cam is to remove the cowling, propeller, alternator, Vac pump, magnetos, fuel lines, carb, exhaust, starter and then remove the engine. From there the cylinders are removed and the crank case disassembled (2 halves). The labor warrants a total overhaul of the engine.
 
Presuming it’s Lycoming the Crank would be a big concern but not too bad

to check.

A new Crank is not part of an overhaul.


I’m referring to internal corrosion per SB 505

You have to pull the plug.
 
Last edited:
How much would the engine concern me? None at all, I'd assume the engine is ready to quit and requires an overhaul.

I'd be more concerned about the owner not wanting to let this creampuff go for less than 30% over the average asking price.
 
If the seller is unwilling to spend the money to give the engine proper maintenance, do you really want to do business with him? I mean, unless you can get the thing for a song...

Seems it's a classic case of an owner looking for the right time to jump ship and pass his problems on to the next unsuspecting buyer in a hot market. But I could be wrong...
 
I might not fly it depending on the amount of metal. Lycoming has pretty good guidance on this: https://www.google.com/url?sa=t&sou...QQFnoECAgQAQ&usg=AOvVaw0iyZkq7ivRhKl7T48ib3q2

If they borescoped the cam, I assume it's a continental, but the guidance still stands as continental doesn't have a similar document. To answer your question, yes I'd assume the engine is done. It may have 1 hour, 10 hours, or 100 hours in it, but more likely the shorter end of the scale. The good news is even if it wipes out a couple cam lobes, it won't catastrophically fail, just lose power.

Not flying it may or may not be an issue. The first time I flew my plane was ferrying her home, but then you're kind of stuck with the shop where it's at. I hear factory rebuilds are 6-8 months out. If you have the money and time to wait, but the seller doesn't, you might be able to buy it cheap. Then you'll be the only one to run the new engine so you'll know it's been broken in properly and babied its whole life.
 
Will Kumley said:
How much would this concern you on a potential purchase? Seller states he is selling the plane as his mech noticed some metal in the oil and after performing a borescope inspection noticed the camshaft had some corrosion and had some wear. States it will likely need to replaced soon. I'm admittedly dumb in this world as I usually work with go fast engines on military aircraft but am I thinking correctly that a camshaft replacement may as well be a full overhaul?
Click to expand...
It would be a big concern to me. I think I would look elsewhere for a plane. Good luck.
 
Will Kumley said:
How much would this concern you on a potential purchase? Seller states he is selling the plane as his mech noticed some metal in the oil and after performing a borescope inspection noticed the camshaft had some corrosion and had some wear. States it will likely need to replaced soon. I'm admittedly dumb in this world as I usually work with go fast engines on military aircraft but am I thinking correctly that a camshaft replacement may as well be a full overhaul?
Click to expand...
Yes. It would make little to no sense to pay/do the labor involved in replacing the cam and having the lifters yellow tagged/replaced and not go ahead and 0 time the rest of the engine. Replacing the cam and lifters adds 0 value to the airplane, a fresh overhaul does.
 
The engine is done from a cost standpoint. You did not give any info as to the type. You need to subtract the cost of a overhual from the price. The engines only value is as a core. As to the issue of flying it you need to find out how much metal it was making and be aware that running it could increase the cost of the overhual if it causes additional damage.
 
If it's making metal, then probably a whole lot of other stuff is affected, like prop governor, oil pump, bearings, you don't know so assume the worst. I'd price in an overhaul. Of course it all depends as to how much you can claw back from the owner, things like the asking price and whether the engine run out are big things.
 
What engine are we talking about? Have you discussed this with the mechanic you intend to use once an aircraft is purchased?

I wouldn’t write this off immediately, based on what has been written so far. Aircraft and engines are fixed every day. If I were going to pursue this I would want to have a pretty good idea on what’s wrong and what it’s going to take to fix. The cost and proper repair may vary greatly depending on what aircraft/engine we’re discussing.
 
Thanks all, I'm calling the mechanic later today but the wait time is a valid point to consider as I really don't want to buy my first plane only to have it in the shop for half a year. This is a Lycoming o-540.
 
Will Kumley said:
Thanks all, I'm calling the mechanic later today but the wait time is a valid point to consider as I really don't want to buy my first plane only to have it in the shop for half a year. This is a Lycoming o-540.
Click to expand...

the picture you’re painting is exactly this scenario. Make it 9mo due to supply-chain issues.
 
It needs an engine. Purchase price should reflect that. If not, walk away.
 
Der Fliegermeister said:
If the seller is unwilling to spend the money to give the engine proper maintenance, do you really want to do business with him? I mean, unless you can get the thing for a song...
Seems it's a classic case of an owner looking for the right time to jump ship and pass his problems on to the next unsuspecting buyer in a hot market. But I could be wrong...
Click to expand...

You could be. I would consider a buying plane with a run out engine so I could start fresh with me being the only operator of the new engine. In fact, I considered selling my very properly maintained plane with an engine nearing it's TBO. I hope selling a run out is not a sign of poor maintenance.
 
Lon Stratton said:
You could be. I would consider a buying plane with a run out engine so I could start fresh with me being the only operator of the new engine. In fact, I considered selling my very properly maintained plane with an engine nearing it's TBO. I hope selling a run out is not a sign of poor maintenance.
Click to expand...
I was actually considering it for this very reason. Get the plane cheap and figure a new/overhauled engine in the mix. I get a nice plane with a zero time engine, seller makes a little money. Win-win. Problem is, I really don't want to wait the current 6+ months for a new/overhauled engine.
 
Will Kumley said:
I was actually considering it for this very reason. Get the plane cheap and figure a new/overhauled engine in the mix. I get a nice plane with a zero time engine, seller makes a little money. Win-win. Problem is, I really don't want to wait the current 6+ months for a new/overhauled engine.
Click to expand...

Don’t give up on it totally just yet. If you’re willing to spend a little time and money on a prebuy inspection from your/independent A&P/IA, it may be something you can safely fly for 10-100 or more hours while you order up your replacement engine. Metal in the filter is not good, but it may not be fatal. Have your A&P weigh-in on the “worn cam” issue before moving on completely.

All we can do on the internet is give you distance advice, some good, some not. And I’m not saying mine is good, lol.
 
Once the cam and lifters start spalling and sending metal to the filter, that engine's days are almost done. It eats itself rapidly. Corrosion is the primary cause of that, and opening that engine is likely to find major corrosion throughout. That's a lot more than a simple fix.

I'd ask the owner if he's been ground-runnning it. A first-class way to ruin an engine.
 
Will Kumley said:
Problem is, I really don't want to wait the current 6+ months for a new/overhauled engine.
Click to expand...
Which is why I took a chance and ordered an engine last month. I'm told I have 3 months after the new engine is delivered to return my engine for core deposit plus the 6-9 months of wait time, so I'm gambling my engine will last another year or so. The gamble is my engine may not need to be replaced when the new one shows up.
 
It is quite likely you will wind up with an overhaul.

But there are other choices that could wind up with time & money

well spent or wasted.

To my knowledge; no one other than his A & P has actually viewed the wear

and type and amount of metal.

There are some folks ( in Louisiana?) that will analyze the shavings and

provide you with the type of alloy and possible sources.

I believe the cost is about $100.

At one time Lycoming would provide the same service.

Now they are much more restrictive with the service.

Possibly they will do ONLY for engines they overhauled are are still

in warranty period.

Not a lot of “ good deals” these days.

This could be your nugget or a turd.
 
Lon Stratton said:
Which is why I took a chance and ordered an engine last month. I'm told I have 3 months after the new engine is delivered to return my engine for core deposit plus the 6-9 months of wait time, so I'm gambling my engine will last another year or so. The gamble is my engine may not need to be replaced when the new one s hows up.
Click to expand...

I have done the same thing last year 2020. I pulled the cyls off my 40 year old 0-320 H2AD with 1700 hrs on it. It was burning 1 qt per 3.5-4 hrs and 2 of the cys were down in compression, 54/80 48/80. This motor sat a lot in it's life with only 1700 hrs in 40 years. The cam did not look bad and the tappets/lifters mostly had corrosion on them, not so much spalling. Although at the time I was not sure about the cam. Oil analysis did not show excessive metal.

I also found piston ring gaps lined up on 3 out of 4 pistons.

I decided to put it back together with all the old parts with new o rings and valve cover gaskets so I could keep flying the plane.
I ordered a rebuilt lycoming engine. Was told it would take 9 weeks to get it. I doubted that since covid was just starting up. It took 12 weeks for the engine to show up. I was fine with that since my old engine was running great.

I spaced the old rings out on the old pistons before I put it back together.

The oil burn went from 1qt per 4 hrs to 1qt to 8-9 hours!!! I was thrilled and very surprised. The motor was running so good I was disappointed I ordered the new engine. I flew the old engine another 100 hours before swapping it. I am sure the old motor would have made it well past TBO

So I let the new engine sit as long as I could before I made the swap. Got the old core engine back to lycoming right before the 90 days and all was good there.

I swapped the new engine into the plane in 7 days 4th of July 2020. I now have 335 hours on it and is doing well.

BTW I ran the oil for a 100 hours in the old engine until I changed it out. I sent a sample to Blackstone just for ****s and giggles. Blackstone said the all metals were within averages and no problems noted with the 100 hour oil.

Now it is a 6-9 month wait time for a lycoming engine? The price of my motor went up $7500. also this year. Wow did I get lucky.
That's my story.

Good luck with your swap.
066.jpg

020_5.jpg

I took the motor off the plane and then decided to put it back on and back together to keep flying it. So swapped it twice in 6 months in and out of the plane. Rings gaps lined up. Yes I know it is not good to leave the rods lay against the case, at the time I was not planning on putting it back together.
030_4.jpg
 
Last edited:
Clip4 said:
The labor warrants a total overhaul of the engine.
Click to expand...

That's not a given under all circumstances. That depends on the age of the engine (calendar year of last OH and current SMOH balance).
 
This being a Lycoming 540, I would like to know how the engine got borescoped well enough to make any assessment of condition. The engine may be okay yet, it’s hard to say without further investigation.
 
Lon Stratton said:
You could be. I would consider a buying plane with a run out engine so I could start fresh with me being the only operator of the new engine. In fact, I considered selling my very properly maintained plane with an engine nearing it's TBO. I hope selling a run out is not a sign of poor maintenance.
Click to expand...
To be fair, a runout isn't necessarily a bad sign. In fact, if the engine has made it to TBO I'd say it was maintained and flown well.

I hear your point about a fresh engine under your own care and I've seen that work out very well in my immediate friend group.

I suppose my initial response did not do so well to encourage these positions of thought so I thank you for jumping in. I think I'd be more afraid of an engine with 50 hours "SMOH" than one with some time under its belt. Fortunately, it seems the bad apple field OHs are becoming more rare as reputable shops are doing well to increase their capacity
 
@Will Kumley, here is a general rule that you should apply: Never fall in love with a deal. Since this is a first airplane it is especially exciting and you will be tempted to comb these responses for comments that are soothing and best-case. This is called "confirmation bias." Don't do it. Read all the worst case comments thoroughly and convince yourself that you will be getting a worst-case engine if you buy this airplane. That is not necessarily bad, because then you control what is done and with your background you'll probably do well. But don't pay a best-case price. Pay a worst-case price or walk.

The cure for falling in love with a deal is to constantly tell yourself that there will be another deal next week, another next month, etc. Also, if you get in a hurry and make an expensive mistake you will remember that for the rest of your life. If it takes you a few months longer to find the right airplane at the right price you will hardly remember the time spent. Say it until your lips bleed: Never fall in love with a deal
 
airdale said:
@Will Kumley, here is a general rule that you should apply: Never fall in love with a deal. Since this is a first airplane it is especially exciting and you will be tempted to comb these responses for comments that are soothing and best-case. This is called "confirmation bias." Don't do it. Read all the worst case comments thoroughly and convince yourself that you will be getting a worst-case engine if you buy this airplane. That is not necessarily bad, because then you control what is done and with your background you'll probably do well. But don't pay a best-case price. Pay a worst-case price or walk.

The cure for falling in love with a deal is to constantly tell yourself that there will be another deal next week, another next month, etc. Also, if you get in a hurry and make an expensive mistake you will remember that for the rest of your life. If it takes you a few months longer to find the right airplane at the right price you will hardly remember the time spent. Say it until your lips bleed: Never fall in love with a deal
Click to expand...
Trust me, not falling in love with any airplane yet. I feel like I'm smart enough to look at it with the attitude of this isn't the one but let me see if it can be the one. In the case of this plane, the seller was up front and honest with the engine condition which I greatly appreciate. Had I called the local shop and they said it would be down for a month if an overhaul or engine was needed I'd probably send an offer contingent on the prebuy inspection. But the 6+ month wait is just too long for me to want to wait right now. If I was on sea duty and had a 6 month deployment to soak up the time I'd be more willing to play the waiting game. But I'm currently on shore duty and want to capitalize my time in the air. I can still rent planes while not paying for a new to me airplane so as of right now the plane that started this thread isn't right for me today.
 
Rgbeard said:
I guess you need to limit your searches to near-zero-time engines.

If you buy a 500-1000hr engine, it might crater on you, too. You just never know.
Click to expand...
I don't necessarily need a zero time engine and I'm sceptical of low time engines as well. I just looked at the logbooks for a plane that has sat for 3 years and only flew 2-3 hours a year from 2015-18. The price of the plane on the surface seemed like a good starting point, but with such a long time sitting I'd rather see the plane get a fair number of hours on the engine and have an oil change or two so the seller and I know if it's going to be a problem.
 
Zero time engines haven’t proven themselves yet. May take 200-300 hrs for weak metallurgy issues to pop up per Dave Weber’s research.
 
I overhauled a 600hr engine a couple of years ago because of cam wear due to spalled tappets from sitting. so TSMO really means nothing compared to how and when that time was accumulated.
 
texasclouds said:
Zero time engines haven’t proven themselves yet. May take 200-300 hrs for weak metallurgy issues to pop up per Dave Weber’s research.
Click to expand...
That's discouraging! I've only flown a brand new engine twice and a newly overhauled engine once.
 
Two good books if you're new to the foibles and failures of aircraft engines:

Manifesto by Mike Busch
Fly the Engine by Kas Thomas

Both are available from Amazon Kindle, and both worth reading g.
 
You must log in or register to reply here.
Back
Top