 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
JonathanMilbank
Joined: 14 Apr 2012
Posts: 394
Location: Aberdeen area
|
 Posted: Sun Nov 05, 2017 3:05 am Post subject: Propeller/engine rotated backwards |
 |
|
What if someone's been turning my propeller/Rotax 912ULS backwards through several revolutions? I know in that case oil will be "sucked" out of the hydraulic tappets and damage would/could be caused to the valve train.
Would I hear clattering on engine start and would the noise continue? Or after initial clattering, would the tappets fill within a few minutes and the clattering disappear? The trouble is that someone else did the first start and he didn't report unusual noises.
The engine has subsequently run for two hours including four flights. Should I now undertake investigations for damage and if so, what should I be doing to put this worry behind me? Rocker covers off and look at valve spring caps? Check magnetic plug? Prime the oil system again to purge air out of the tappets?
Your advice would be very welcome, thanks.
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
|
|
| Back to top |
|
 |
Roger Lee
Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.
|
| Posted: Sun Nov 05, 2017 8:43 pm Post subject: Re: Propeller/engine rotated backwards |
|
|
If you keep doing that not only will oil be displaced, but you'll ruin the sprag clutch on the starter and that usually means pulling the engine. Removing the back end of the engine and replacing th4 sprag clutch. That will be expensive.
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056 |
|
| Back to top |
|
|
JonathanMilbank
Joined: 14 Apr 2012
Posts: 394
Location: Aberdeen area
|
| Posted: Mon Nov 06, 2017 2:34 am Post subject: Re: Propeller/engine rotated backwards |
|
|
As I said "someone's" possibly been doing it and it wasn't me. Regarding sprag clutches, if my propeller gets turned even slightly the wrong way then it can clearly be heard and felt that the starter motor is being driven backwards through the sprag clutch. There is an extra resistance to turning the propeller and a whirring sound.
Having already had the sprag clutch replaced when changing from the old style starter to the longer-bodied starter motor, I've seen and understand what's involved in that job. I removed and replaced the engine myself and don't wish to repeat that anytime soon!
So going back to my main concern, I'm keen to know if running the engine will get rid of air in the tappets, in which case that's already happened, or is bleeding the oil system the ONLY way to achieve this?
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
|
|
| Back to top |
|
|
gilles.thesee(at)free.fr
Guest
|
| Posted: Mon Nov 06, 2017 4:19 am Post subject: Propeller/engine rotated backwards |
|
|
Le 06/11/2017 à 11:34, jonathanmilbank a écrit :
| Quote: | | Quote: |
So going back to my main concern, I'm keen to know if running the engine will get rid of air in the tappets, in which case that's already happened, or is bleeding the oil system the ONLY way to achieve this? |
|
Jonathan,
Let's say it is the only way to achieve peace of mind 
SI-912-018 is really no big deal, if it were my airplane I'd perform it and clearly label my prop with a "never rotate backwards" sign.
And why not craft a prop cover with something preventing rotation of the prop -unless some harm to the engine is deliberately meant ?
FWIW
--
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
|
|
| Back to top |
|
|
JonathanMilbank
Joined: 14 Apr 2012
Posts: 394
Location: Aberdeen area
|
| Posted: Mon Nov 06, 2017 5:04 am Post subject: Re: Propeller/engine rotated backwards |
|
|
Gilles, you've hit the nail on the head with "unless some harm to the engine is deliberately meant ?", but when a friend went flying in my aircraft after it had not flown for 4 weeks, he later told me that it started perfectly first time with no unusual noises. I only spoke to him after I started this topic, when I had also flown the aircraft and thought the engine was less smooth.
I have done SI-912-018 a couple of times previously, so I'll probably take your advice and do it again. However it would be useful to know from someone who has experienced it before, whether the engine makes noises caused by hydraulic tappets with air trapped inside. I imagine it would sound a bit like an old diesel engine, only quieter.
Perhaps I'm just being too suspicious of someone who is known to have done underhand things before, but not as serious as this!
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
|
|
| Back to top |
|
|
Roger Lee
Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.
|
| Posted: Mon Nov 06, 2017 5:37 am Post subject: Re: Propeller/engine rotated backwards |
|
|
If you can actually hear the tappets because you have that much air in the system you are going to damage and bend things. These are hydraulic lifters and need oil to function properly.
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056 |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
