Question for Paul McBride, the General Aviation News engines expert: I put my 1959 Cessna 182 in for its annual inspection and we found a cylinder with low compression. After pulling the cylinder, my mechanic says the engine needs overhauled due to the condition of the cam and lifters. I replaced all lifters four years ago. Why would the lifters be pitted? Looking at the cam do you think it should be torn down?
The existing overhaul has 800 hours on it, but it was done in 1991. I bought the plane in 2016 with 120 hours on the overhaul.
Mark Spencer
Paul’s Answer: Mark’s problem is a good example of a situation that is common in the world today. And with the cost of avgas these days, we’re entering a time where more and more aircraft will be idle for long periods of time — and the results could possibly be even worse than what Mark has seen here.
I hate to be the bearer of bad news, but from the pictures and information you presented, I’d say if this were my engine, we’d be on the way to an engine overhaul.
Even with the information you provided, I have to read between the lines and try to use some common sense to give you the reasoning behind my answer. I think the most important thing is just looking at the spalling on the lifter faces and the same on the one cam lobe.
If you cut your oil filter open, I wouldn’t be surprised if you found metal contamination. If there isn’t any metal contamination found, I’d almost bet that if you continue operating the engine, you will see some soon.
It’s for this reason that I’d recommend having the engine overhauled.
Not to say that just replacing the lifters at this point wouldn’t allow you to get a few more hours of flying out of this engine, but we know the contamination will continue, and that might lead to who knows what?
Worse case scenario, it could possibly lead to an engine failure, depending on the amount of contamination.
The important thing to remember is this: We know the spalling has begun on both the lifters and the cam lobes. If you only replace the lifters, this will not stop the cam lobes from continuing to spall. Once any metal is displaced on either part, there is no stopping it if the engine is continued in service. At some point, it may result in enough contamination that it will ruin other expensive parts, such as the crankshaft.
I realize that you bought the aircraft in 2016 with only 120 hours on it Since Major Overhaul (SMOH). If we look at the overall situation here, we’re talking about an engine that is 63 years old and has had one overhaul already that we know of.
My guess is we’d find that there has been a lot of extended periods of inactivity for this airplane. As I’ve mentioned many times in the past, coupling infrequent operation with infrequent oil and filter changes sets us up with the worst possible conditions for an engine to enter the nasty state of internal corrosion. It’s a hard, cold fact that infrequent operation and infrequent oil and filter changes shorten the life of any engine, and sadly, you’re seeing the results first hand.
I realize all of this may come as a real blow to you, but the condition of an engine this old is not unusual. My best advice is to take action now and have the engine overhauled.
Curious if you have any information on the model borescope used here? I can view with a rigid in this clarity however none of the Digital ones I have used can get this sort of clarity and take photo’s? Thanks in advance
I worked on the most beautiful 182 right after I got out of college that had 30 hours on it with a ground lifter and a flat cam lobe so I feel your pain but change it overhaul it because it won’t be 110% and if it’s not 110%. It’s not worth your life
We had a similar situation with our 1980 Mooney M20J. Purchased with only 900 or so hours on the overhaul, but that overhaul was from 1996. We bought the airplane in 2020. I really woke the airplane up, flying over 100 hours in our first year owning it, but that year was pockmarked with engine problems due to inactivity. Sticky valves, clogged fuel injection system fouled spark plugs, dirty starter bendix, to name a few. We immediately commenced 50-hour oil changes with lab analysis, and replaced all the peripherals (fuel injector system, spark plugs, prop governor because ours was failing, and magneto, as well as all supporting hoses, etc.). We have the exhaust valves boroscoped and reamed. Compressions aren’t perfect but they are acceptable. The engine runs strongly now, and each oil analysis reveals improvements in metal content. We plan to fly her another year and then revisit an overhaul. Bottom line, long-term sitting isn’t any better for a machine than it is for the human body. It allows entropy to take hold and set in more easily. Even though our airplane had been hangared, it had endured years of inconsisent, sparse use, and we paid for it (fortunately, not with our lives). I’d say keep exercising the airplane and closely monitor its performance with a good engine moniter that records data, and make sure you get frequent oil changes and lab analyses. Best of luck!
Very good idea
Before you decide to overhaul, get another opinion from another source. One I’d recommend is Savoy Aviation Services. Send them the pictures and cut open the oil filter [ they’re inexpensive compared to an OH ] and send pictures of what is found in the filter. I feel they will tell you what they feel is right for you.
I would suggest consider an IRAN, still expensive, but a lot less than Overhaul.
https://skygeek.com/telyenoilad6.html?utm_source=googlebase&utm_medium=shoppingengine&utm_content=telyenoilad6&utm_campaign=froogle&msclkid=a9f381614e3515ec1ffee2775714ed9c
Consider a upgraded engine. If the crank won’t turn, good luck finding one below 6k
Expensive either way
My experience
As was mentioned/implied, Fuel prices will have more impact on the condition of the GA fleet, than we could’ve ever imagined. To the masses, “compression’s” are THE only part of the puzzle. How many times have we heard, “all the cylinders are in the mid to high 70’s”, as a [the] factor for buying or selling an airplane? Moisture must be “cooked” out of the crankcase and a taxi around the airport or a run-up in front of the hangar, doesn’t do it. Oil additives or running a dehumidifier in your hangar will help, but is not the “fix all-cure all” solution.
Unfortunately, the “$100, er’ $300 dollar hamburger” or tossing your keys to another qualified pilot [to use/exercise your airplane] may be the only option against early engine mortality. The alternative (to a $20-30K overhaul) is “exit stage left” and look for an “Evinrude”…..
I think I have a better example, Austo engines may be used for only 12 years, on an age of 12 years they need to be replaced, even if they have only 300 hours on it. That is a waist of money. The 12 year old engines are worthless, no core, you can keep them as an very expensive souvenir.
So, reviewing SID 05-1B, the corrosion pitting looks to be minor, and TCM would recommend running the engine for some time to see if the corrosion is ‘healed’ by some added wear.
The pitting on the cam appears to be on the heel, where pressures are the lowest, and not on the lobes.
I own a 1960 in 60 AERO commander under 680F I had the Cam load problem that you’re talking about When you start the engine up It I don’t rough like it had a smart point problem When it warmed up it was OK The 60F is supercharged charged so we’re flying the engine didn’t care because the supercharger took over We pulled a cylinder and you could find out There is also a bond of cameras where I have a 1960 aero commander 680F I’ve Is head the Cam was worn The engine acted like it had a spark plug problem problem when it warmed up in the flu it the supercharger didn’t care anything about a bad valve I pulled both engines and overhauled them There was an engine shop It’s certified for Cam oilers I installed 4 Cam oilers in both engines but And boring all the cylinders and took the choke From them I can send you a copies of the literature Or call me 7143498009
and he stated a compressor didn’t need a lot
Refer to Continental Motors SID 05-1B for guidelines on camshaft and lifter corrosion.