Oil change

[Al Downs]

When changing the oil and filter does all the oil drain out or is some trapped somewhere? The book says it hold 3.1 quarts. It seems a full three quarts is close to over filling.

[Roger Lee]

Al,

 

Just rotate the prop, then drain the tank and change the filter. Then add your 3 qts. it will take it to the top of the stick. A good place to be. The only trapped oil is in the lines, oil cooler and in the engine. If you drain any other oil other than the tank or break open the system and oil drains out or you rotate the prop with the oil tank empty or the oil filter off then you must do an oil purge. If you fail to do this then you may collapse a lifter since they can't pump air and then it's time to buy another engine because repairs would be about $10K-$12K . There is absolutely no reason to try and drain a few more ounces of oil. When you drain a car not all the oil comes out and you don't pull it apart to get the rest.

[Al Downs]

That is how I did it. It just seemed like it was a little too full.

 

Thanks Roger

[Tip]

If you are using Aeroshell Sport Plus 4,it is in liter bottles. I have found that three liters will overfill on an oil change.

[Roger Lee]

The nice thing about a dry sump engine is you really can't over fill so that it may harm an engine like a car or some other engine. The only thing you can do in a dry sump like the Rotax is over fill to the point that it spills out the vent tube up in the neck of the tank. Usually 3 qts. Or Lts will only fill to the top of the dip stick. Remember the 3 qts has to fill the oil filter too. The only way 3 qts. would ever be too much is if you don't burp the engine first and you have one of those engines that siphone back a lot of oil into the bottom of the crankcase. I have seen as much as 2 qts siphone back, so make sure you burp the engine before you drain the tank and by no means turn the prop after the tank is open and drained.

[Greg]

Oops.

 

Roger.

 

My last oil change I turned prop after draining to get more old oil out. ( Bad move per your current post.) Filled oil to correct level. Flew three routes in pattern. Standard practice after any maintenance that I learned from this forum. No problem. Left pattern and flew one hour in area and then EMS started showing high oil pressure. Landed. Next day flew one hour to check for problems. No problems. Five days later flew to Nashville. After two hours the high pressure alarm started acting up for the last 30 minutes. On and off, but seemed that if I reduced RPMs, the pressure dropped within green. Sometimes it cleared without any action on my part. Three days later in preparing to fly home, I wiggled the connector to the oil pressure sender. 2 1/2 hours home. No high oil pressure. Have not flown since.

 

Seems to me I either had air in system, or bad connection to sender. Maybe bad sender. Or coincidence? Never had high oil pressure before. 170 hours.

 

Any thoughts? Any suggestions? Do I need to purge air or wait to see if I have more high pressure.

 

I really appreciate your willingness to help the CT group.

 

I wanted to send this PM due to my ineptness, but realized others may learn from my mistake.

 

Greg.

[Roger Lee]

Hi Greg,

 

Your very lucky you didn't get enough air in to collapse a lifter. With the numbers of hours you have in now I don't think an oil purge will help. I don't think I would play that lottery game again unless you have some big bucks handy. The high swing on the oil pressure can be a loose connector, but many times it's a bad ground. For now just keep an eye on things and you may want to tighten the 5 grounds. It only takes about 20 min.

[Runtoeat]

Reminder: Remove the magnetic plug and check it for metal chips at every oil change to insure that 1. the engine is not producing abnormal metal and 2. the visual check for amount of accumulated metal is not "failed" which would require engine tear-down.

[Roger Lee]

Hi Dick,

 

I might add the mag plug check is mandatory for every oil change as per Rotax. It only takes a couple of minutes and unless your lazy there is no reason not to do it. I have only seen two that were a disaster. One had a large metal chip on it from a broken tooth from a gear and the other had a fine dust beard on it from a bad lifter that ground down. There will be no warning of these types of things. They happen instantly so a mag plug check should be an absolute must at the oil change.

[Tom Baker]

Hi Dick,

 

I might add the mag plug check is mandatory for every oil change as per Rotax. It only takes a couple of minutes and unless your lazy there is no reason not to do it. I have only seen two that were a disaster. One had a large metal chip on it from a broken tooth from a gear and the other had a fine dust beard on it from a bad lifter that ground down. There will be no warning of these types of things. They happen instantly so a mag plug check should be an absolute must at the oil change.

Roger, can you dirrect me to the document that says that. I guess I'm just blind , but I have not been able to find it in print.

[Runtoeat]

Tom, the Rotax Line Maintenance manual refers to the mag plug check. 5-20-00 pg. 14 and 12-20-00 pg 57. The Rotax oil change schedule was every 100 hours if using Mogas and 50 hours if using 100LL but Rotax now recommends oil change interval of 50 hours for mogas users. Since Rotax wants the mag plug checked at each oil change per the manual, I follow the new oil change interval and check the plug at 50 hours also.

Rotax_line_ed2 rev1_7-1-10.pdf

[Roger Lee]

Here you go.. The mag plug is supposed to be checked at each oil change.

 

It is in the Line Maint. manual under checking the magnetic plug and in Rotax SB-912-051 dated Jan. 2008

 

http://legacy.rotax-owner.com/si_tb_info/serviceb/sb-912-051ul.pdf

[Tom Baker]

Tom, the Rotax Line Maintenance manual refers to the mag plug check. 5-20-00 pg. 14 and 12-20-00 pg 57. The Rotax oil change schedule was every 100 hours if using Mogas and 50 hours if using 100LL but Rotax now recommends oil change interval of 50 hours for mogas users. Since Rotax wants the mag plug checked at each oil change per the manual, I follow the new oil change interval and check the plug at 50 hours also.

Rotax_line_ed2 rev1_7-1-10.pdf

 

Dick, the checklist says to check it at 100 hours, and not every oil change. I also think you have your hours backwards. Rotax used to say 25 for 100LL and 50 for auto and then changed to the 50/100 times. They also changed sparkplugs from 100 to 200 at the same time. Personally I still use the lower change times, but check the magnetic plug per the checklist.

[Tom Baker]

Here you go.. The mag plug is supposed to be checked at each oil change.

 

It is in the Line Maint. manual under checking the magnetic plug and in Rotax SB-912-051 dated Jan. 2008

 

http://legacy.rotax-owner.com/si_tb_info/serviceb/sb-912-051ul.pdf

 

Roger, that SB doesn't apply to any of the engines I work on based on serial number. It also says that the plug must be check at every mandatory oil change which would be the 25 hour check for a new engine, each 100 hours if using auto fuel, and 50 hours if using more than 30% 100LL. It doesn't say every oil change. I take this to mean that if using auto fuel the plug must be checked every 100 hours, also since the annual uses the 100 hour checklist then it is also a annual item regardless of the number of hours since the last oil change.

[Roger Lee]

Hi Tom,

 

The Rotax classes don't use those old extended numbers for oil changes. 25 hrs for 30% (not for just a new engine) or more of 100LL and 50 for 91 oct. The 25 hr oil change you mention is part of the warranty check done at 25 hrs., but oil is done every 25 if you use 100LL too. They also teach to inspect the plug every oil change. The newer version of the maint. manual says to change oil every 25 hrs with 100LL use. Then it says 100 hrs for 91 oct. but no one I know uses this 100 hr change if they have been to school. I have seen a few use this 100 hr oil change, but it isn't advised. The plug inspection is an annual check item as it states in the manual. One of the Rotax SB's says to check it every oil change, but I'm not looking through them to find it.

[Al Downs]

Hi Tom,

 

The Rotax classes don't use those old extended numbers for oil changes. 25 hrs for 30% (not for just a new engine) or more of 100LL and 50 for 91 oct. The 25 hr oil change you mention is part of the warranty check done at 25 hrs., but oil is done every 25 if you use 100LL too. They also teach to inspect the plug every oil change. The newer version of the maint. manual says to change oil every 25 hrs with 100LL use. Then it says 100 hrs for 91 oct. but no one I know uses this 100 hr change if they have been to school. I have seen a few use this 100 hr oil change, but it isn't advised. The plug inspection is an annual check item as it states in the manual. One of the Rotax SB's says to check it every oil change, but I'm not looking through them to find it.

 

Where is this magnetic plug?

[Roger Lee]

Hi Al,

 

It's a secret only the mechanics know.

 

See the attachment. It's in the Line Maint. Manual and Parts Manual.

Mag plug.pdf

[Al Downs]

Hi Al,

 

It's a secret only the mechanics know.

 

See the attachment. It's in the Line Maint. Manual and Parts Manual.

Thanks Roger. I will check it next oil change. I am sure if I try now, some oil will drain. I just changed the oil a couple of days ago.

[Tom Baker]

Thanks Roger. I will check it next oil change. I am sure if I try now, some oil will drain. I just changed the oil a couple of days ago.

 

Some oil may come out regardless. If one of my boys are around I have them hold their finger over the hole.

[Tom Baker]

Hi Tom,

 

The Rotax classes don't use those old extended numbers for oil changes. 25 hrs for 30% (not for just a new engine) or more of 100LL and 50 for 91 oct. The 25 hr oil change you mention is part of the warranty check done at 25 hrs., but oil is done every 25 if you use 100LL too. They also teach to inspect the plug every oil change. The newer version of the maint. manual says to change oil every 25 hrs with 100LL use. Then it says 100 hrs for 91 oct. but no one I know uses this 100 hr change if they have been to school. I have seen a few use this 100 hr oil change, but it isn't advised. The plug inspection is an annual check item as it states in the manual. One of the Rotax SB's says to check it every oil change, but I'm not looking through them to find it.

 

Roger, when I first took my Rotax training in 2008 the line maint. manual still had the 25/50 hour intervals if I remeber right. Then it changed for my re-current training to the current 50/100 hour interval. Since you said that it needs to be checked every oil change I tried to find where it says that. I've never been able to find it in any of the documents. The manuals and documents are what we have to go by regardless of what was taught in class. I agree that changing the oil at the shorter intervals is a good thing even if the manual says I can go longer. I see no problem checking the magnetic plug every oil change , but to say you have to do it does not go along with the documents except for the engines listed by serial number in the SB.

[Roger Lee]

Hi Tom,

 

25 is written somewhere. If I wan't so tired and headed to bed I would even look.

[Runtoeat]

I know a lot of you have had the Rotax training and know a lot more about this but I asked a Rotax technician at Sun-N-Fun what his personal thoughts were regarding hours between oil changes. He didn't hesitate and said 50 hours and went on to tell me that this interval does make a difference by showing much less wear and tear on high hour engines. The other comment I might make is Rotax Line Manual states that only a 3mm build-up of metal on the mag plug is allowed. If the amount of metal exceeds this, the manual says the engine must be inspected. Personally, I inspect the mag plug each oil change and clean it off. The 3mm allowed build up then starts fresh. If one lets this go a few times, there is the possibility that the 3mm build-up can be exceeded when the mag plug is finally checked.

[Jim Meade]

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.

 

 

[Roger Lee]

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

[Tom Baker]

I know a lot of you have had the Rotax training and know a lot more about this but I asked a Rotax technician at Sun-N-Fun what his personal thoughts were regarding hours between oil changes. He didn't hesitate and said 50 hours and went on to tell me that this interval does make a difference by showing much less wear and tear on high hour engines. The other comment I might make is Rotax Line Manual states that only a 3mm build-up of metal on the mag plug is allowed. If the amount of metal exceeds this, the manual says the engine must be inspected. Personally, I inspect the mag plug each oil change and clean it off. The 3mm allowed build up then starts fresh. If one lets this go a few times, there is the possibility that the 3mm build-up can be exceeded when the mag plug is finally checked.

 

Dick, I agree that the 50 hour oil change is a good thing. I change mine every 50 hours or sooner. On checking the magnetic plug I have a different thought. If it is to be checked every 100 hours and 3mm is allowed by checking then cleaning every 25 hours you might not catch the problem that it is intended to catch. I check the magnetic plug at the 100 hour or annual inspection. I really think that if there is a problem it will show regardless of how many hours since the plug was checked.