I too have had this problem twice, each time around 650 hours with a Lycoming 0320 E2D.
After the latest failure the engineer who does the maintenance suggested that I insert cowl caps at the end of the flight to slow down the cooling.
He also recommended a different technique for starting, priming the engine as usual and then start the engine with the Throttle Closed and increase the RPM very slowly until 1200 is reached.
I hire the aircraft out and he thinks that Pilots are opening the throttle far too much for start up.With an overhead cam shaft it is relativley dry before oil gets round the gallery to lubricate it.
This new method works for me and I have now done a further 751 hours,(fingers crossed) I use 15/50 oil and have the oil analysed at every change.
I have heard that the FAA have approved a modification that allows the cam shaft to be lubricated from a separate oil source before starting.
While in Australia I came across the same problem with an aircraft that was in a warm enviroment and hangered.
After the latest failure the engineer who does the maintenance suggested that I insert cowl caps at the end of the flight to slow down the cooling.
Even if you believe in the existence and validity of “shock cooling” (which I do not), this doesn’t make much sense as the camshaft is inside the engine case and it is not exposed to the cooling airflow. Only the cylinders are.
He also recommended a different technique for starting, priming the engine as usual and then start the engine with the Throttle Closed and increase the RPM very slowly until 1200 is reached.
That does make a lot of sense and it should be clear that any other technique is harmful. You should start the engine with the minimal RPM possible until the splash lubrication is at full effect. My POH actually recommends doing it that way.
The only factor for Lycoming camshaft longevity that I consider to be substantial is manufacturing quality. Lycoming have a history of selling very very bad camshafts. You find engines that are being terribly abused by all standards and camshafts working to TBO and much beyond and you find a lot of engines being pampered by conscious operators that fail after 650 hours like you mentioned. You’re a victim of a crap quality product, nothing else really…
The only factor for Lycoming camshaft longevity that I consider to be substantial is manufacturing quality. You’re a victim of a crap quality product, nothing else really…
+1 !
I would think that one clue is in “longest between flights 32 days” which is too long. You get rust forming well before 30 days is up.
I don’t think this is a terribly big factor. We had a similar failure in a Cessna 172 at the flying club I used to fly with in Houston. That C172 had the wings flown off it, always – some months it would do over 100 hours. Lycoming O-320-H2AD. We decided that “AD” in the engine designator stood for “airworthiness directive”.
Sadly the plane was destroyed by the last hurricane that went through Houston, the hangar collapsed on it.
Has anybody proven that the Lyco metal (in disintegrated camshafts and can followers) was crap?
I don’t believe so.
It’s not an expensive test. A few hundred quid perhaps?
I am aware of one such test where the exact opposite was found i.e. the metal was perfect. It pointed to the engine having been standing around (under a previous ownership) for a long time and getting corroded. I would like the owner to go public with it. Until then I can’t talk about it.
We could have a debate on how long it takes for rust to form and how much it matters when it does form. I don’t think anybody has hard data on it. But I know my cast iron brake disks are rusty after a few days. OK; they are very exposed. So there will be a scale of severity, and the humidity (or specifically the %RH because that is the “condensation potential”) will be a big factor, as well as proximity to the sea, etc.
But there are so many pointers from all over the place to corrosion being a factor in these disintegrations that I would never buy any aircraft that has been sitting around for months anywhere near the sea or anywhere in Europe unless the engine overhaul was discounted in the price and I did the OH before flying it.
I know there are people who say they know a data point proving the opposite and I completely believe them but it is probably not something you want to bet on on a % chance basis.
Here’s an example of why Lycoming cam issues are enigmatic… A Grumman Traveler powered by an O-320 with a recent overhaul…. after it appears 40 years since new and over 2200 hrs, well beyond recommended TBO. Mine is similar except only 1000 hrs TT – which is why I’m interested. Link
Incidentally the plane looks to me like a good deal for somebody.
A very interesting read went from Post 1 till now.
Heres my opinion and Ill state why afterwards: The stuff we are getting from the manufactures is pure crap. No let me rephrase that CRAP.
I had an IO550L from the factory with new logs. 0 time engine installed in 2007. The plane was in a heated dehumidified private hangar. It had a tanis dehydrator applied after every flight once I blew out the air for 5 mins from the crankcase. Oil changed on average 30-40 hrs. Camguard used from 2011 on. Filters were cut open and oil analysis Blackstone was used. The plane was flown 120 hrs /yr with at most a 2 week interval. I flew over the latter half of 2012 to Europe. I still use the plane once every 2 weeks. My total flight hours are less than 80hrs/yr. It is in an unheated hangar with the dehydrator applied but now in addition has dehydrator plugs in the exhaust stacks. The plane is preheated below 40F or 4C.
With that background in mind. In 2014 had heard of lifter spalling problems. So even though I had never had even a sliver of metal in my Oil filter or any abnormal metal in the Oil analysis I decided to proactively check the lifters. All the lifters looked great except 1 which had some minor spalling. According to Cont it was ok to keep in service because it may not get worse. Instead I did some research and found a supplier with better lifter reputation and replaced the spald lifter. The cam looked good. Thankfully.
Its very easy to say pilot error or its because of a humid environment or lack of use.
Ive got a 1977 BMW Boxer with no environmental controls, sits for 7 months a year, gets ridden about 2500 mi/yr, and its not falling apart and thats without camguard!
There is absolutely no way anyone can tell me that the lifter should have gone bad with the way that engine was cared for. Its interesting that the 11 other lifters were fine. I spoke with Cont. about it and they said it was difficult to determine quality because the lifter surface may not have uniform hardness. They can test 99 out of 100 all will pass save one. They cant explain why this is happening. I suggested they stop using 3rd world countries and bring production of lifters to Germany. Im told I am not very tactful at times. Basically inconsistent quality control or manufacturing is the culprit. Thats what I got out of that conversation. Since most of the manufacturing is outsourced to the cheapest manufacturer in some 3rd world country and as long as the paperwork meets specs who cares if the only thing that crashes is our wallets? The fact that all of US aviation is under one corp roof begs the question what happened to the concept of monopolies and antitrust?
So I think when you put it all together you get a picture of just crappy quality from companies who make even more money by producing substandard products. Thereby having less incentive to change. Im sure if people crashed and had lawsuits things would change in a hurry. I was always of the opinion that corp execs should be held in criminal court if they knowingly made a product that injured people without trying to rectify the problem.
With two dominating suppliers of almost identical products in a shrinking market, there is no competition and no reason to innovate or excel. The worse the product quality, the better for them as they can sell expensive parts. Lycoming made a ton of money on the crankshaft AD. In a normal industry, customers would stay away from such companies.
The biggest hope lies in the diesel aero engines. Takes a lot of time though.
The biggest hope lies in the diesel aero engines
Mr Thielert p1ssed on that bonfire well and truly, setting the whole business back at least 10 years.
But looking at the wider picture, yes we cannot remove an IO540 and drop in something else (a Conti engine is no better; it merely has different weak points) but with a diesel aircraft you cannot change the engine anyway. So nothing changes as regards your options as a consumer.
I’d say the diesel engine makers have a better hold on your balls than Lyco or Conti – because “anybody” competent can rebuild one of those without any reference to the manufacturer (let’s debate separately how many engine shops in Europe can be trusted to do a good job) but almost nobody can touch any aero diesel, and AFAIK the parts are all tightly controlled by the engine manufacturer.
Another problem is that the majority of Thielert production appears to have gone to the FTO business and they are notoriously non-open about issues. One FTO put out a press release praising Diamond and saying how great a relationship they had with the factory – while they had 3 out of their 4 aircraft grounded and were just short of litigation! To be fair this was ~3 years ago… these things tend to improve.
But if I had to choose between having my balls squeezed by Lyco or having them squeezed by Mr Dries, I would choose Lyco every time. It’s always possible to have the cam followers lab tested for hardness.
Time will tell how this pans out.
In the last ten years cam and flat lifter problems have become a significant issue for a lot of different engines, not just Lycoming engines. Google ‘cam lifter failure’ and a lot of links are returned. I’ve personally seen quite a number of motorcycle engines with pitted lifters, flat cams and the like, across several different manufacturers, For example Piaggio Group is having problems right now and has switched to roller lifters, but it changes from year to year. The usual explanation for the problems is recent changes in the oil, driven by government environmental requirements that I believe wouldn’t apply to aircraft oil. That’s curious to me, as is the fact that in the ‘real’ world outside of forums I’ve known of just one Lycoming cam failure among a great many engines owned and used by friends and acquaintances.
Assuming the oil hasn’t changed, and not wanting to start an ‘oil thread’, my guess on Lycomings is that it may have to do with the lubrication applied during break in, and the break in procedure. There aren’t a lot of potential causes that are so random.
I use cam guard in my motorcycle engines, to prevent this… Look familiar?
