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Roger Lee
Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.
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 Posted: Sun Dec 20, 2009 6:51 pm Post subject: New Rotax Maint Manual Changes |
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Hi All,
Just thought I would do a little reflecting on just a couple of the new Rotax "Line Maint Manual" changes.
I don't think they are all good for us, but that's my personal opinion and may not reflect your perspective.. Please no one get worked up over this as these are just some items I happen to see when reading through.
1. Compression test is every 200 hrs. which is the same as the old manual, but the change is you can use a test pressure of 80-87 psi.
87 psi was the old standard test pressure. 80 psi test pressure was for A&P's that didn't know better, now they will at least look like they knew. I always do a compression test at every 100 hrs. or annual for my clients. It only takes a few minutes and might point to a problem much earlier.
2. The gearbox check was moved from 800 hrs to 1000 hrs. for those that use 91 oct. unleaded. For those that use 100LL more than 30% of the time then a gearbox check is due at 600 hours. That usually means those that are using a lot of 100LL will need to have the overload clutch sent in a cleaned of all the lead deposits. Only a couple of places in the US does this. You can't do it yourself very well because you need a jig, a special tool and a lot of force. CPS does this cleaning.
3, To me this next one isn't such a good idea. They did this many years ago and had some issues then.
Only check, clean and gap the plugs at 100 hrs. and replace at 200 hrs. If you have seen many plugs with those time intervals and flown some of those engine with 100 plus hours with 100LL then this is still a bad idea today.
The plug gap recommendation has changed a little. It is still within the older specs, but is slightly different from the old manual. New gap recommendation is .023-.027. Most everyone I knew used to gap at .028 for warmer weather from April -Nov. They used to say you could gap as low as .019 for really cold weather. Doesn't say anything about the lower gaps in the new manual. Good question when I go back in Feb. for my Rotax update class.
4. Here is one I really lift an eyebrow about.
Looks like they went to 50 hrs. on the oil and oil filter change for 100LL and 100 hrs. if you use 91 octane unleaded.
If they were so adamant before about sooner oil and oil filter changes being detrimental to the engine all these years, what happened to change that? If the 100LL made such a mess and it did if you ever saw and engine apart why has that changed?
The oil is the blood of your engine and you just got a TBO extension, why play with the success that got that extension in the first place. Personally 50 hr. oil changes still work for me, but it's up to each owner. I would highly recommend, plus your supposed to do oil analysis to be compliant with the new TBO and it should be done anyway. Cost is a whopping total of $19.95. The kit can be ordered from Lockwood and postage is all prepaid. You get the results online. Once every 100 hrs. should be good.
5. This is just a reminder on this item. Your gearbox friction test results should be between 264-531 in/lbs. The higher the better especially for cold weather starting. If you are in the mid to upper 400's then great. If you are in the low 300's you may need a shim or spring washer change sooner than later.
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Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056 |
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lucien
Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM
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| Posted: Mon Dec 21, 2009 6:20 am Post subject: Re: New Rotax Maint Manual Changes |
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| Roger Lee wrote: | Hi All,
Just thought I would do a little reflecting on just a couple of the new Rotax "Line Maint Manual" changes.
I don't think they are all good for us, but that's my personal opinion and may not reflect your perspective.. Please no one get worked up over this as these are just some items I happen to see when reading through.
1. Compression test is every 200 hrs. which is the same as the old manual, but the change is you can use a test pressure of 80-87 psi.
87 psi was the old standard test pressure. 80 psi test pressure was for A&P's that didn't know better, now they will at least look like they knew. I always do a compression test at every 100 hrs. or annual for my clients. It only takes a few minutes and might point to a problem much earlier.
2. The gearbox check was moved from 800 hrs to 1000 hrs. for those that use 91 oct. unleaded. For those that use 100LL more than 30% of the time then a gearbox check is due at 600 hours. That usually means those that are using a lot of 100LL will need to have the overload clutch sent in a cleaned of all the lead deposits. Only a couple of places in the US does this. You can't do it yourself very well because you need a jig, a special tool and a lot of force. CPS does this cleaning.
3, To me this next one isn't such a good idea. They did this many years ago and had some issues then.
Only check, clean and gap the plugs at 100 hrs. and replace at 200 hrs. If you have seen many plugs with those time intervals and flown some of those engine with 100 plus hours with 100LL then this is still a bad idea today.
The plug gap recommendation has changed a little. It is still within the older specs, but is slightly different from the old manual. New gap recommendation is .023-.027. Most everyone I knew used to gap at .028 for warmer weather from April -Nov. They used to say you could gap as low as .019 for really cold weather. Doesn't say anything about the lower gaps in the new manual. Good question when I go back in Feb. for my Rotax update class.
4. Here is one I really lift an eyebrow about.
Looks like they went to 50 hrs. on the oil and oil filter change for 100LL and 100 hrs. if you use 91 octane unleaded.
If they were so adamant before about sooner oil and oil filter changes being detrimental to the engine all these years, what happened to change that? If the 100LL made such a mess and it did if you ever saw and engine apart why has that changed?
The oil is the blood of your engine and you just got a TBO extension, why play with the success that got that extension in the first place. Personally 50 hr. oil changes still work for me, but it's up to each owner. I would highly recommend, plus your supposed to do oil analysis to be compliant with the new TBO and it should be done anyway. Cost is a whopping total of $19.95. The kit can be ordered from Lockwood and postage is all prepaid. You get the results online. Once every 100 hrs. should be good.
5. This is just a reminder on this item. Your gearbox friction test results should be between 264-531 in/lbs. The higher the better especially for cold weather starting. If you are in the mid to upper 400's then great. If you are in the low 300's you may need a shim or spring washer change sooner than later. |
A couple thoughts:
The grade of oils we have available now are probably significantly better than when the initial interval was proposed. Our auto oils are up to API grade SM now (and maybe past that by now, havn't looked lately) and the Aeroshell is SJ or SL can't remember offhand. Those grades are significantly better than what was probably available at the time.
So I'd say, if the motor is being run a lot an interval like 25 hours is probably excessive, even when running 100LL. Perhaps this is just a field experience thing? The last time I ran a significant amount of 100LL over an oil change interval (last year sometime) I changed at 25 hours; oil was really black indicating to me it was doing a good job scavenging the lead and was still very "oily" and not watery. That was with an API SM auto oil (vavoline IIRC) before switching to the Aeroshell which I'm using now.
One thing I kind of wish they'd do is recommend a time limit along with with hours (or if they do I wasn't able to find it?). Just seems uncomfortable to me that you could conceivably change the oil only at annual if you're flying 100 hours a year..... I personally start to get uneasy once the oil gets to around 6 months old and I go ahead and change by then regardless of hours. But that might be covered too under the later API specs as well. Havn't looked at the newer ones on the API site.
Same thing on the spark plugs. On mine when I was running 100LL, they looked a lot worse than they actually were when I pulled them at annual. I think they had around 100 hours on them with more than 30% 100LL and I was still getting a perfect mag drop on both sides. I still change mine at annual tho since it's cheap and they have to come out for compression check anyway.
I'm also glad about the longer gearbox inteval. Don't know about anyone else, but I'd rather wait as long as possible before taking my motor apart  . But seriously, they should emphasize the MOI limit here, IMO. It's amazing the gigantic tonnage props that are put on these things out in the field and I'm sure they're hammering the boxes really good. That's why I love my powerfin, the entire engine is so much happier
Just my thoughts about it,
LS[/i]
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LS
Titan II SS |
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Dick Maddux
Joined: 24 Jun 2008
Posts: 516
Location: Milton, Fl
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| Posted: Mon Dec 21, 2009 6:27 am Post subject: New Rotax Maint Manual Changes |
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Roger ,
Thanks for taking the time to summarize the major changes !! That's a great help !
Dick Maddux
Milton,Fl
[quote][b]
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