Spalled Camshaft

G44 said:

Which oil was the first? My guess would be the 15-50. Right? Wrong?

Kurt

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Yes the 15W-50 went soon after application and rust formed within a month. That was the earlier formula. Later they added the Lyc anti-scuff or whatever else to fortify the product and I redid the test later. Same results. 1st to go 15W-50, then the 20W-50XC, last was the older white can 50W but not the current updated Aeroshell W100, or even better yet their W80 or W100 plus with even better anti-wear and corrosion add packs. I have no interest in Shell products-disclaimer.

Base was my 500 gallon fuel tank. I sanded off the side coating to bare steel and cleaned with alcohol. I then applied an equal amount of the three oils about one ounce from a shot glass and let them run down the tank's side. The 15W-50 ran the fastest and furthest, followed by the 20W-50, and last the aeroshell 100. The 100 never rusted much and the 20W-50 was also better than the early 15W-50. Temps were Fairbanks summer and it rained. Lasted over two months and by winter the straight 50W was still holding hands with the steel and had flies stuck to it. The rest were gone.

Gary

This is not another oil thread in respect for the OP's problems. But recall that these engines were certified on straight weight 30-50 oils un-compounded without additives or not later when ashless dispersants were available. Then the magical world of multi-vis oils were then offered and whatever changed as far as wear patterns blew out like a sneeze. A history of cylinder and valve wear over the span of the available lubes would inform. I use what was offered back when they were developed and certified.

Gary

astjp2 said:

Stuck valves probably caused all of the problems. Just like a Hammer on the cam and lifters.

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windy said:

The spalling is on cylinder #1 intake & exhaust lobes and one of the cylinder #2 lobes (the exhaust, I think). Interestingly, cylinder #1 was the only cylinder that never had any sticking valves.

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This is telling us that the stuck valves and potential hammering was not the cause of the cam failure.

Robinson R-22 and R-44's have a rigorous inspection protocol. That includes the valves. If interested go search when and why. They are aware of potential problems and how to diagnose and hopefully prevent. Example: http://www.covehelicopter.com/robinson-r44-maintenance/scheduled-maintenance/

Gary

BC12D-4-85 said:

This is not another oil thread in respect for the OP's problems. But recall that these engines were certified on straight weight 30-50 oils un-compounded without additives or not later when ashless dispersants were available. Then the magical world of multi-vis oils were then offered and whatever changed as far as wear patterns blew out like a sneeze. A history of cylinder and valve wear over the span of the available lubes would inform. I use what was offered back when they were developed and certified.

Gary

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Did Aviation oils back then contain any Zinc?

I know they quit using zinc in today’s car oils (epa), so a lot of these classic cars, older vehicles, and race engines would ruin there cam shafts from lack of zinc, especially fresh rebuilt engines. So now they make a “zinc rich” oil specially blended for these cars.

There's zinc and also the detergency issue. Multi-vis oils tend to have detergents added, the purpose is to carry crud to the paper-element filter. No paper filter, no hi-detergent oils allowed. You're strirring it up and circulating it.

It's a disservice to the engine manufacturers, Lycoming in this case to suggest that they haven't improved their engines since they were first certificated.

Do you seriously believe that Lycoming isn't aware of the changes and improvements in lubricants over the decades? These engines have in fact changed significantly in many ways most of us will never know over the years.

And, that's not to suggest that every one of those changes has been a stellar success....

But, believe me, Lycoming is well aware of the additives in modern oils.

MTV

Ash from detergents, antiwear additives, and combustion byproducts can form and promote piston ring and valve sticking in some engines. Antiwear zinc was tried and discarded in one aviation oil as it allegedly caused problems according to some feedback from users. There's aftermarket additive products available that claim antiwear anticorrosion properties with minimal ill effects. And the point about detergents and filters liking each other is true.

As far as factory improvements as Mike notes I suspect that's true, but the potential issue for valve wear and/or sticking remains (or Robinson's maintenance schedule in #34 wouldn't be as rigorous). Surface coatings like nickel, chrome, valve rotators, added supplies of cooling oil can help if the engine or components are modern in design. But for some of us flying ancient engines (small Continentals) there's only a few options for improvement like ECI implemented before they left the building.

High localized cylinder heat is an enemy that can be both detected and observed...CHT/EGT/oil temp and pressure/surface paint discoloration/borescope exams/...all can build a case for proper air/fuel delivery with sufficient cooling oil to the valve train and airflow over the cylinders. And even then if the cam and lifters spall or valves stick who is to blame despite the operators best efforts to prevent?

Gary

mvivion said:

It's a disservice to the engine manufacturers, Lycoming in this case to suggest that they haven't improved their engines since they were first certificated.

Do you seriously believe that Lycoming isn't aware of the changes and improvements in lubricants over the decades? These engines have in fact changed significantly in many ways most of us will never know over the years.

And, that's not to suggest that every one of those changes has been a stellar success....

But, believe me, Lycoming is well aware of the additives in modern oils.

MTV

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Very good point Mike! What is funny is how many aviation folks keep thinking that utilizing all the new electronics and such would be a great improvement in engines... while the working owner/operators with big diesels tend to curse all the new engine 'improvements'. There are fishermen looking for older engines to install in their boats after having brand new engines 'code' a problem and shift to limp mode forcing a return to port in a time critical fishery. Stories of this happening to multiple engines, and multiple times to the same engine reinforces the need for simplicity in my aircraft.

And Windy, misery loves company. My engine has been red tagged due to the camshaft. :-( Life is not easy all the time.:-(

Another point: Back when Continental discovered a bad batch of crankshafts in their big engines, some resulting in accidents, I ran into Paul McBride, Tech Rep for Lycoming, and congratulated him on dodging that bullet. He smiled and said “Actually, we didn’t”. Turns out there was only one foundry in existence that made crankshaft blanks for aircraft engines. They produced ALL the crank blanks for Continental and Lycoming. Lycoming lucked out in that none of the “bad” cranks in their engines had been sold to customers before Continental discovered the problem, and Lyc recalled all the engines.

Which begs the question: How many outfits out there making cam blanks, valves, etc for these engines?

This was precisely the problem Frank Robinson encountered early in his helicopter business: outsourcing parts, in his case rotor blades. He fixed that by taking everything back in house except engines. Paul McBride told me that when Frank called Lycoming, things got done, since he was the biggest user of their engines.

But some of this stuff makes one ponder manufacturing defects on outsourced parts....

MTV

Mike,

another really good point.

Talking with my fuel supplier here last month he told me there is ONE refinery making 100LL. Most won't deal with it due to low volume and the lead and other base metal requirements creating more EPA trouble than it is worth.

Only so many factories around making lube oil, it was five 25 years ago.

Let's home we can outlive the 100LL supply.

aktango58 [emoji25]
We’re in this together!


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windy said:

aktango58 [emoji25]
We’re in this together!



Sent from my iPhone using SuperCub.Org

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I will offer you a cold drink on the deck if you wish to visit.

I am waiting for the State to get out the Highway project we have been anticipating being out to bid for the last year... told by the end of the month for the last three months. That is my engine "Go fund Me" account. Need a big project to cover these unexpected things. But, I am just happy this was found in the shop, not in flight.

aktango58 said:

And Windy, misery loves company. My engine has been red tagged due to the camshaft. :-( Life is not easy all the time.:-(

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What oils were used?

Gary

BC12D-4-85 said:

What oils were used?

Gary

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I bought the plane about 4 years ago with just under 1100 hours. I believe it was then using Aeroshell 15-50. Since I have been using Phillips XC 20-50.

40 year old engine. Not surprised to have internal issues.

Thanks for the reply and sorry to hear about the corrosion problem. It's too common to ignore as being acceptable.

I'm biased towards Aeroshell W80 or W100 Plus. Too much experience with 15W-50 or 20W-50 shearing down to lower grade and potentially lower oil pressure (depends on dispersed solids content) plus corrosion. Anything that needs a substantial additive package plus base oils to function as a multi-vis concerns me. At standard daily temps they are thinner (15-20W) so can drain off parts sooner. They thin like straight oils when heated but due to the add package not as much to meet the 50W viscosity range at 210*F. Eventually when the additives wear out so can the viscosity.

We preheat when cold anyway so when oil pours unheated is of little consequence unless oil cooler congealing is experienced.

Gary

Usually, camshafts wear badly when lifters pit. This is caused mostly by long periods of inactivity. Think about the combustion process, by-products are Carbon Monoxide; Carbon Dioxide; Sulphur Dioxide, and water. Mix Sulphur Dioxide (S02), with condensation (water) (H2O), and we get H2SO4, sulphuric Acid, that eats and eats at metal, easily at the cam followers, where the oil drips away first, and when the lifters are exposed to the acid and air, they pit. The result is a spalled cam. I just OH the engine of my 2003 Top Cub, 200 hours total time over 17 years. The logs show the engine was serviced with preservative oil during periods of inactivity, but I found all 8 lifters corroded and pitted, drive gear corroded, corrosion in the cylinders, valve seats, and crankshaft. Spent a lot of money to make it righteous, but now have a "new" and reliable engine, runs great. Also.... Heat accelerates molecular activity. Having an engine on a "goldenrod" or other heaters all the time to keep moisture out will often accelerate acid erosion. Best to fly it often, and the less flown, the more often oil should be changed, drain out all that acid! Flight school engines I have OH are regularly run, but "tortured"! Full throttle, chop the power, full throttle, chop the power, you get the idea! More often than not, at 2000 hours, they look great inside!! Finally, when I change the oil, I cut open the filter, swish the fabric in clean solvent or lacquer thinner in a clean pan, use a magnet in a baggie, and if it looks like Richard Prior's hairdo, bite the bullet, split the case and regrind the cam, regrind or replace the lifters, before it eats at anything else!!

ps Don't you wish Lycoming lifters could be removed without splitting the case like the Continentals?

Regards,

Gary Brown

I totally agree with your comments, Gary. I don’t think that was the issue with my spalled camshaft, though. I flew that engine 2,250 hours in 8 years. Changed the oil every 30-50 hours & added CamGuard on all but the break-in oil.

SOMETIMES, THINGS JUST WEAR OUT! I bought a Piper Comanche with 3600 hours on the engine, never had a cylinder off. I called Lycoming, asked if they wanted to see a high time engine. They asked how many hours. I told them. They were not impressed, said to call them when I had a HIGH time engine! Go figure!

g.

In #46 I mentioned liking Shell's single grade Plus oils. Here's some more info> https://www.shell.com/business-cust...centre/technical-talk/techart14-30071535.html

They also make a 80W Plus or 40W for my small Continental.

Gary

Lets see....Oil for an Air Cooled, high EGT, long stroke, low RPM engine... Hmmmm, good for my Harley Davidson??

Sure might be ok as HD's are low pressure high flow mostly ball or roller bearing engines. The clutch pac's in the primary and transmission has it's own hole so they also can use a straight 50W like Formula+ or ?. HD's 360 or SYN3 might be cheaper tho for the engine.

Gary

ExConPilot said:

SOMETIMES, THINGS JUST WEAR OUT! I bought a Piper Comanche with 3600 hours on the engine, never had a cylinder off. I called Lycoming, asked if they wanted to see a high time engine. They asked how many hours. I told them. They were not impressed, said to call them when I had a HIGH time engine! Go figure!

g.

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I recall the engine on the PA-18A I used to fly towing gliders had somewhere around 7 or 8000 hours when it finally spun a bearing on me.


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ExConPilot said:

Lets see....Oil for an Air Cooled, high EGT, long stroke, low RPM engine... Hmmmm, good for my Harley Davidson??

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I ran unused left over Philips 25/60 and 100LL that was drained from junk round engine airplanes, in my old 70’s air cooled BMW R90 Motorcycle, smelled like a Cessna 150. Ran perfectly fine.