Oil change

[Tom Baker]

I would have thought that 2 instances of 2mm metal at 50 hours is the same as 1 instance of 4 mm metal at 100 hours. The engine wear is different?

 

I'm hoping that before this thread ends we get references for Rotax' current guidance on oil change interval.

 

Jim, Rotax instructions say 100 hour if running auto fuel, but I like the 50 hour service interval much better. Clean oil and filter is not going to hurt the engine. Tom

[Tom Baker]

A Rotax tech and IRC did answer. I write the articles on the Rotax Owner forum and answer the questions there on tech items.

 

I would still like to see where it says to check the magnetic plug every oil change. So far all I've seen is to check it at 100 hours and maybe 50 for the engines using av gas covered in the SB you mentioned.

[Roger Lee]

Howdy Tom,

 

Tom's quote:

" I really think that if there is a problem it will show regardless of how many hours since the plug was checked. "

 

I'm with you on fresh oil is the blood of the engine and let it get old and diseased and we may give the engine an early overhaul. $12K overhaul could have been saved by a couple of $50 oil changes.

 

As the saying goes: Pay now or pay later. It's a choice and a gamble. Some win and some loose.

 

The idea is to catch a problem as early as possible so it might get corrected before more serious damage can occur and be more costly. If your into an oil change what's an extra 10 minutes of safety inspection and possible cost reduction. So if your flying roughly 100 hours a year with 50 hour oil changes that's only one extra ten minute check every twelve months for peace of mind.

 

Or you may be looking at this that should have been caught at 50 hours instead of a gearbox destruction and or shut down before 100 hrs. This would have been missed for another 50 hrs if it hadn't have been caught early. I have another plug pic that has a major metallic dust beard on it if I can find it I'll post it to.

[josjonkers]

Just curious what the difference is between inspecting your oil filter for metallic filings versus the magnetic plug?

 

If the filter inspection is clean of metallic particles could the plug still show these?

 

Next question relates to non magnetic material which obviously would not show up on the plug but would on the filter inspection, right?

[Tom Baker]

Howdy Tom,

 

Tom's quote:

" I really think that if there is a problem it will show regardless of how many hours since the plug was checked. "

 

The idea is to catch a problem as early as possible so it might get corrected before more serious damage can occur and be more costly. If your into an oil change what's an extra 10 minutes of safety inspection and possible cost reduction. So if your flying roughly 100 hours a year with 50 hour oil changes that's only one extra ten minute check every twelve months for peace of mind.

 

Or you may be looking at this that should have been caught at 50 hours instead of a gearbox destruction and or shut down before 100 hrs. This would have been missed for another 50 hrs if it hadn't have been caught early. I have another plug pic that has a major metallic dust beard on it if I can find it I'll post it to.

 

Why not check it after every flight?

You actually took my statement wrong. I was trying to say that you might be OK by checking it more often (every 25 or 50 hours). On the other hand, you could be masking a problem by checking and cleaning more often the stated in the manual.

[Roger Lee]

Hi Jos,

 

With a very recent and dramatic experience the answer is yes it will show up on the plug before and maybe not at all in the oil filter. The non metallic particles will hopefully show up in the filter and some can and will get by the filter to the oil tank. Not particles, but metallic dust which will absolutely trash all your bearings and render the engine useless. I just saw this first hand.

The best way to inspect a filter is to remove the paper element, put it in a jar with a lid and an inch of gasoline and shake the contents. This will wash everything out of the filter. Remove the paper element and inspect it, but it should be completely clean. Pour the jar contents through a white paper towel as a strainer into another container. The residue will show the smallest and most elusive particles and they will stand out regardless of their composition.

 

I thought I had a video posted of this, but I can't find it.

[josjonkers]

Hi Jos,

 

With a very recent and dramatic experience the answer is yes it will show up on the plug before and maybe not at all in the oil filter. The non metallic particles will hopefully show up in the filter and some can and will get by the filter to the oil tank. Not particles, but metallic dust which will absolutely trash all your bearings and render the engine useless. I just saw this first hand.

The best way to inspect a filter is to remove the paper element, put it in a jar with a lid and an inch of gasoline and shake the contents. This will wash everything out of the filter. Remove the paper element and inspect it, but it should be completely clean. Pour the jar contents through a white paper towel as a strainer into another container. The residue will show the smallest and most elusive particles and they will stand out regardless of their composition.

 

I thought I had a video posted of this, but I can't find it.

 

 

 

Thank you Sir!

[Jim Meade]

Over the weekend, I gave a ride in my SW to a friend who used to be an engine maintenance guy for United.  He said that when money got tight, they started working with the engine manufacturer and even with other air carriers to determine what are safe and fiscally appropriate engine times.  He said they had started with some sections being inspected after 16,000 hours and XX number of cycles.  Over the course of a number of years, they had extended the normal tear down times to 28,000 hours and he had seen some engines with sections that ran over 32,000 hours.  They monitored termperatures and other factors to determine when to overhaul the section.

 

Rotax has a lot of experience with these 912 engines. Unless the engine is operated in a severe envirionment, I can not see any reason why excess maiintenance is of any benefit.

 

As a minimum, a responsible, experienced mechanic should know and advise clients of current manufacturer and regulatory requirements. If there are good reasons to recommend an enhanced maintenance schedule that may be appropriate, but I can not see a circumstance in which the required schedule is not clearly articulated so the client clearly knows and the client (not the mechanic) makes the decision on what maintenance do authorize.

 

 

 

 

 

[Roger Lee]

Who here has over 20 years research, development and real time use of the 912? Who here has spent millions to do all this? So who here can say what is excessive, reasonable or normal maint? Who here realizes this is not another engine, but a Rotax so any past experience with another engine may not apply. Who here relizes the 912 is more lie a motorcycle engine and not a jet engine or an air cooled engine? There are many Rotax owners out there that have spent thousands fixing problems because they didn't follow Rotax recommendations and listened to someone who has never been to a Rotax school, has never downloaded a single Rotax manual or read said manuals.

With tens of thousands of Rotax engInes on the market since 1929 I think Rotax has a reasonable handle on what works in the long run and what doesn't.

Anyone can gamble and try to save money, but can't complain if it leads to excessive and very costly engine failure. Don't kid yourself it is documented regularly and happens way to often. Owners that go to the Rotax schools and see first hand damage from poor decisions and the very costly repairs don't short themselves on maint. Nor do they usually tell people to cut maint. corners.

Time to step down off my soapbox before my age causes me to fall off.

 

 

 

[Doug G.]

This discussion has gone on for a long time. It seems to me that good inspections are important and some things are assential to do on a time basis, but I also feel that there are many things that can be done "on condition." Fot instance, if the oilfilter shows little wear, filter analysis shows nothing of concern, the mag plug shows nothing, the plugs are relatively clean, tje engine burns little or no oil, the compression test shows nothing amiss, and the EMS has not given any indications of problems, why do an ovethaul? Is there a fatal weakness in the structure of the engine that catastrophically fails sortly beyond 2K hours that Rotax is keeping a secret? Why was the 1500 hours extended to 2K? Evidently 1500 was not a correct number and the condition of the engines did not warrent it. So Rotax decided that a better "on condition" number was 2K. Now, Rotax is taking a conservatine shot-in-the-dark when they don't know how my particular engine has been treated, or what the inspections show.

I think that unless Rotax is withholding essential engine information affecting safety, overhaul on condition is not taking chances, it is sticking with an engine you know is good. I suspect there are other items that fall into the same category.

As I undersand it (outside of warranty issues) a mechanic doing an annual, or other inspection can only informthe customer of issues and then leave it to th customer to make the repair decisions at which point the mechanic can release the plane noting the discrepencies and note the airworthiness. At that point the plane is the responsibility of the owner. The plane can't be held hostage due to a didagreement on what needs to be done - even if it affects the airworthiness of the plane. (The owner/pilot better not fly it without accomodation from the FAA however.)

Someone else want to use the soapbox now? :-)

[Doug G.]

Sorry for the typos - tablet keyboards aren't the best.

[Jim Meade]

Roger, you totally missed the point of my anecdote about the United mechanic. I was talking about a maintenance philosophy. The United mechanic said some mechanics were so upset at the changes to longer cycle times that they quit their jobs rather than adapt to better science, yet there were no safety issues with the engines. The deal is, the mechanics were worshipping a false god. Next time I won't be so obtuse.

 

You and I will never agree on maintenance philosophy because you believe the mechanic should make the decisions and I believe the owner should make the decisions.

 

 

[Roger Lee]

I don't think the mechanic should make all the decisions. What I think, is like going to a doctor, CPA, lawyer or auto mechanic, you should be involved in all decisions, but they should be based on good solid education and experience and not hearsay or poor education. I always include my clients in decisions and if they don't know what's going on I can help on the education side and then let them help make the decision. Some do rely on the mechanics knowledge way too much because like a doctor they think they have all the answers or an owner has no first hand knowledge of the engine in question. If your mechanic has not been to a Rotax school, has no manuals, doesn't have or can't even find a SB or says he does it this way on a Lycoming you may want to re-think letting them make the decisions.

 

I also think time changes on engines and maint changes come from time proven experience. It isn't a fast process as it needs thousands of hours to prove or dis-prove a theory. Flight maint. changes are good and i have no issues with increased times or even less maint, but peoples lives are at stake and way too many commercially in jet liners and private aircraft have died trying to make a point so some reserved and a take a step back approach and look at it hard needs to be done first.

 

The reason the TBO went from 1500 hrs to 2000 hrs was Rotax re-designed the crankcase. So everyone with an engine from around Aug. 2006 has a different crankcase than others before. That was the difference. Too many with the older crankcases thought they knew more than Rotax and set engine / prop RPM down around 5100-5200 WOT rpm and cracked crankcases, leaning the engine without knowledge of long term affects, leaving hoses on for 10 plus years because they look good, using 100LL and not doing the gearbox inspection at 600 hrs so the 100LL has rendered the clutch useless and ruined the starter sprague clutch.. Another example of some owners knowing more than Rotax, after Rotax said explicitly not to do that then the owners blamed Rotax because the case cracked. With the newer design that is less likely. Another example is owners not using the proper oil. There are still Rotax owners out there using straight mineral based oil. So inspections do show up junk on the mag plug and oil analysis. People still not using proper plug gaps, over sized props and prop weights, no slipper clutch test and allowing the weak Bellville washer pressure to damage the gearbox, improper hoses on the engine that split and cause total engine failure, no carb balance every 100 hrs. so the engine beats itself to death over the haul, no knowledge on how to check for air leaks so you have a piston scoring from failure to service the carbs. I could go on and on, but this is the reason Rotax has checks where they do and want a trained eye to look for these or educate the owners. When an owner does something through act or admission the first thing they do is blame Rotax and or has caused an incident which looks bad for everyone. This checks are in the owners best interest to make it to 2000 hrs and beyond. They say that never happened to them before when they did the same thing to a Continental or Lycoming. I bet Rotax wishes they had a dime for every time they heard that statement. they could quit making 4500 engines per year and drop to zero and still get rich.

Doesn't anyone think that Rotax may have a good reason for specific checks or replacements that you may not know about. Rotax inspection periods are like any other hazardous endeavor with a little safety factor built in for some things and some things have no leeway in their execution so I doubt after 80+ years of engine Mfg that Rotax pulled numbers and procedures out of a hat. With tens of thousands of engines on the market, more than 4 million flight hours, 4500 new engines per year, engineer's for engine research, cad programs, engine labs and owner's follies to add to the list I'm sure Rotax is way ahead of all of us that have owned a Rotax for a few years.

Being a writer and tech on the Rotax Owner website I get calls from all over the US and World on a daily basis and I can't begin to tell you how much damage people have done to their engine because they don't follow the manuals, listened to Joe Blow neighbor or said that never happened to them when they did that on a Continental and then call me to see how bad the damage is and the approximate cost. That said I get just as many that want to know the right thing to do so they aren't on the repair list and spending $1K-$8K when it could have just been $50-200 for the preventive maint. The problem is on timed tables you never know when it will fail, not a single person and anyone that thinks they can is like a lawyer that represents himself. So time limits are there to protect you, Rotax and more importantly the passenger who trust you have made a good well educated decision on keeping the plane up so you don't kill a family member or friend, you don't spend the kids college money on an expensive repair.

 

The issues here and around the world is lack of education before making a decision or comparing two different engines. That's why Rotax wants people to go to a school. The schools also have information that are not in the manuals and is new enough to not be in print for quite some time.

Before you rely on just your own judgment at least know all there is to know on the other side from the MFg. then you'll be well versed to make a real educated decision.

 

The normal Rotax owner will never see or hear about all the people that damaged their engines so history will repeat itself. So break the chain and be informed, go to school.

We all think we know this much ................., but we didn't know there was really this much to know..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

It's doing it right!

 

 

Damn, just sprained my ankle falling off the soapbox. I guess I was there too long. Didn't hurt my typing fingers though....

[Doug G.]

FYI Roger I am going to the 120 hr LS repairman course (which includes Rotax) at OSH in September. I believe in being informed about things.

Three questions: 1) Is it possible that some mechanics do more than necessary and thus cost owners more than necessary by taking advantage of the lack of knowlege?

2) With the internet, why does Rotax take so long to disseminate important infomation?

3) Why is wordwrap not working? (At least on my machine.) :-)

Doug

[Jim Meade]

Roger, the point is you are not content to advocate for Rotax times. You strongly recommend maintenance more frequently than Rotax says. The strong impression I get is that you pressure the owners to accept your interpretation rather than Rotax. One has to keep in mind that when one goes to a CPA or doctor, the professional does not make the decisions.l They make write the document and plan the treatment, but at some point the person makes the decision and accepts the responsibility. The CPA will be careful to tell you that he will go into the IRS meeting with you but will also make sure you know that it is your money he is talking about, not his.

 

Now, I, on the other hand, like to see maintenance done by condition. i will freely admit that my maintenance schedule on my airiplane is influenced by a "not broke,don't fix it" attitude for which I accept full respnsibilty. Of coures, I have an Experiemental airplane.

 

I suspect we've entertained the masses enough on this that I'm going to drop it, except that I promise that if I think you are pushing your personal preferences over Rotax guidance, i will feel free to point it out.

 

 

[Tom Baker]

Roger, I don't know if the soap box was intended for me or not, but I have had Rotax training and I keep it current. I follow the Rotax maintenance manual and SB's for times and procedures that need to be done, and it says to check it at 100 hours. You say Rotax knows best, so that's why I follow their documents and check it at 100 hours. If Rotax wants me to check it every oil change then they need to change the documentation or issue a SB. If you think it needs to be done at every oil change, then you need to ask Rotax to make the change. I think checking it to often could lead to skewed results just like doing oil analysis on fresh oil. Tom

[Roger Lee]

Jim,

 

I resent your strong worded implications and you are way off base about it to start!

 

I never push extra maint on anyone, but I do follow the Rotax manuals and yes I do bend those rules at times depending on each individual situation. That decision gets made from years or experience, many Rotax classes over the years and working on 30 LSA aircraft a year.

Jim if your going to accuse me of something then have that many repeat Rotax classes, years of Rotax experience and 30 + aircraft a year in maintenance and write technical articles for Rotax behind you to make those educated decisions and informed accusations. I don't think any of my customers would agree with you on my over charging and forced extra maint. accusation.

Why do you think Rex in Tulsa and I get so many aircraft into our shops. Not because we make them do extra maint and overcharge them. Show me another shop that is doing that many SLSA a year? I'm may be one of the least expensive SLSA shops in the country. (no overhead) If you're going to point fingers at myself and people like Rex you may want to find another direction to point. Your way off base.

I never push, but educate and then the owner and myself make the call. If he doesn't want something done I won't do it and depending on what it is I will log it a such in the book that it was his choice. I never advocate more than what's in the manuals, but I find more problems than most mechanics because they just don't spend the time to look carefully enough or have the training to know what to look for.

My customers are all my friends and I will not allow them to go when I know it could cost them a plane or their life. Your maint has to last more than 10 hrs. You own a plane and it cost money. If your not willing to do what's right then another safer hobby may be in order. The problem with on condition is people wait until next year rolls around and that may not be acceptable, nor does any one have x-ray eyes to look under fire sleeve or through metal.

[Roger Lee]

Thank God for unscheduled maint. I found this little problem this morning on a client that flew in.

 

This jumps right on the post in another thread about a recent broken wheel. Keep the tire pressures up, don't let them get low, look at the wheels after a hard landing, YES I know it is unscheduled maint. and takes 10 minutes. This could have been done with low pressure, a hard landing and who knows maybe some side loading on the landing.

 

 

Heck, I didn't even over charge him for a new part. I gave it to him for free! I didn't force him to replace it either. I replaced this and all three tires and updated his Dynon for a whopping charge of $175 parts and all. The wheel alone would have cost $350+ and that's after you found one.

[Roger Lee]

Hi Tom,

 

No soapbox aimed at you at all. Your my buddy.

 

The whole idea behind checking the mag plug at every oil change is to catch things early before they do serious damage or cause a forced landing. Some things do break quick and catastrophically and some slower. We hope to find the slower occurring problems.

 

All the oil in the engine passes by this plug so any magnetic particles should stay. This is the same thing I used to do flying helicopters, but and some of those are checked before each flight depending on the chopper and service it's in.