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Oil in exhaust, Rotax 914

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frans(at)paardnatuurlijk.
Guest

Posted: Wed Oct 21, 2009 6:54 am Post subject: Oil in exhaust, Rotax 914

Hi everyone,



Today, after some months of working on the airplane, I decided to start

the engine again. I noticed some time ago that the bottom of the turbo

was a bit "wet". The engine ran fine (and for the first time without

overheating during the long ground session), but after the succesful

test I noticed that the exhaust had blown quite some oil away. There was

a dark spot on the ground where the exhaust points to, and the port

wheel was soaked with oil.

The inside of the exhaust was dry, so the oil came out early in the

session. The oil was not burned, I assume it came out of the turbo.



Now, I would like to know whether it could (hopefully) be somewhat

normal that after a few months of non operation the turbo seeps full

with oil, and on engine start this oil is thrown out of the exhaust.

If this is not normal, what is involved with fixing this?



Almost flying, but new issues come up faster than I can solve them... 



Frans

pete(at)lawless.info
Guest

Posted: Wed Oct 21, 2009 8:04 am Post subject: Oil in exhaust, Rotax 914

Hi Frans 



I have no experience of the 914 but do own a turbo charged Twin Com.  The

seals on the turbo are made by burning oil.  When the turbos were changed

the oil leak into the exhaust was alarming.  A leak also happens when the

engines are not run for a few weeks (like now when the Government have

screwed our economy and Stirling does not by much in Europe!).  As soon as

the engines are flown the problem goes away.



So without knowing the individual engine I would guess your oil leak will

clear with running.



Regards



Pete



--

ptag.dev(at)tiscali.co.uk
Guest

Posted: Wed Oct 21, 2009 12:28 pm Post subject: Oil in exhaust, Rotax 914

Hi! Frans,

I had a similar problem on first engine run. I actually siphoned about 1/4

litre of oil from the muffler after the initial run.

I think there could also be a matter of inhibitor discharge. I think the

consensus will be run it further and get it up to normal operating temps and

it will clear and reseal the ceramic seals.

Regards

Bob Harrison G-PTAG 



--

Ivor Phillips

Joined: 16 Jan 2006
Posts: 253
Location: London UK

Posted: Wed Oct 21, 2009 11:12 pm Post subject: Oil in exhaust, Rotax 914

I concur with Bob, Had exactly the same problem on start up after a long period of not being used, Even last winter lay up for maintenance aprox 2 months, She through out some oil then settled down,

Ivor



---- Robert C Harrison <ptag.dev(at)tiscali.co.uk> wrote: 

[quote] 

 

 Hi! Frans,

 I had a similar problem on first engine run. I actually siphoned about 1/4

 litre of oil from the muffler after the initial run.

 I think there could also be a matter of inhibitor discharge. I think the

 consensus will be run it further and get it up to normal operating temps and

 it will clear and reseal the ceramic seals.

 Regards

 Bob Harrison G-PTAG 

 

 --

frans(at)paardnatuurlijk.
Guest

Posted: Thu Oct 22, 2009 1:06 am Post subject: Oil in exhaust, Rotax 914

ivor.phillips(at)ntlworld.com wrote:

 	  Quote: 	
		   

 

 I concur with Bob, Had exactly the same problem on start up after a

 long period of not being used, Even last winter lay up for

 maintenance aprox 2 months, She through out some oil then settled

 down, Ivor


	


Thanks (to you and the other repliers) for the reassurance that my

engine is not broken. One item more I can take off my to-solve list.



Frans

europa(at)pstewart.f2s.co
Guest

Posted: Sat Oct 24, 2009 2:58 pm Post subject: Oil in exhaust, Rotax 914

Frans



I know you have had reassuring responses to this - I asked the very same

question of Conrad Beal (UK Rotax service centre) when he came up to our 914

recently. He confirmed others view that this is normal especially when not

run for a while. Indeed he told us to expect oil streaks down the cowlings

to start with.



Regards



Paul

G-GIDY

About the same position as you!

On 21/10/09 15:52, "Frans Veldman" <frans(at)paardnatuurlijk.nl> wrote:



 	  Quote: 	
		   

 

 Hi everyone,

 

 Today, after some months of working on the airplane, I decided to start

 the engine again. I noticed some time ago that the bottom of the turbo

 was a bit "wet". The engine ran fine (and for the first time without

 overheating during the long ground session), but after the succesful

 test I noticed that the exhaust had blown quite some oil away. There was

 a dark spot on the ground where the exhaust points to, and the port

 wheel was soaked with oil.

 The inside of the exhaust was dry, so the oil came out early in the

 session. The oil was not burned, I assume it came out of the turbo.

 

 Now, I would like to know whether it could (hopefully) be somewhat

 normal that after a few months of non operation the turbo seeps full

 with oil, and on engine start this oil is thrown out of the exhaust.

 If this is not normal, what is involved with fixing this?

 

 Almost flying, but new issues come up faster than I can solve them... 

 

 Frans

litesellme(at)YAHOO.COM
Guest

Posted: Sat Oct 24, 2009 7:18 pm Post subject: Oil in exhaust, Rotax 914

If the ball in your check valve doesn't make a good seal, it will fill up the turbo oil drain box due to gravity feed. When you go to start it, you will bleed oil past the turbo seal until the oil coming in equals the oil being scavanged from the secondary oil scavange pump. Any back pressure at all will cause oil to feed past the seal. Despite what you have been told, this is really bad on a stock 914. The oil will gum up the wastegate, and you will boost spike!! I've seen more than a handfull of engines that have boost spiked to over 28PSI due to this problem and turbo control issues. If your burning oil all the time then it is one of the following, your turbo needs to be rebuilt, your oil check valve is not poping at 65 psi and over supplying the turbo, or your secondary scavange pump isn't working properly. 

 Jason



--- On Sat, 10/24/09, Europa <europa(at)pstewart.f2s.com> wrote:



  	  Quote: 	
		  

From: Europa <europa(at)pstewart.f2s.com>

Subject: Re: Oil in exhaust, Rotax 914

To: europa-list(at)matronics.com

Date: Saturday, October 24, 2009, 3:37 PM



 --> Europa-List message posted by: Europa <europa(at)pstewart.f2s.com (europa(at)pstewart.f2s.com)>



Frans



I know you have had reassuring responses to this - I asked the very same

question of Conrad Beal (UK Rotax service centre) when he came up to our 914

recently. He confirmed others view that this is normal especially when not

run for a while. Indeed he told us to expect oil streaks down the cowlings

to start with.



Regards



Paul

G-GIDY

About the same position as you!

On 21/10/09 15:52, "Frans Veldman" <frans(at)paardnatuurlijk.nl (frans(at)paardnatuurlijk.nl)> wrote:



 	  Quote: 	
		   --> Europa-List message posted by: Frans Veldman <frans(at)paardnatuurlijk.nl (frans(at)paardnatuurlijk.nl)>

 

 Hi everyone,

 

 Today, after some months of working on the airplane, I decided to start

 the engine again. I noticed some time ago that the bottom of the turbo

 was a bit "wet". The engine ran fine (and for the first time without

 overheating during the long ground session), but after the succesful

 test I noticed that the exhaust had blown quite some oil away. There was

 a dark spot on the ground where the exhaust points to, and the port

 wheel was soaked with oil.

 The inside of the exhaust was dry, so the oil came out early in the

 session. The oil was not burned, I assume it came out of the turbo.

 

 Now, I would like to know whether it could (hopefully) be somewhat

 normal that after a few  months of non operation the turbo seeps full

 with oil, and on engine start this oil is thrown out of the exhaust.

 If this is not normal, what is involved with fixing this?

 

 Almost flying, but new issues come up faster than I can solve them... 

 

 Frat; http:========================


	


	


         [quote][b]

frans(at)paardnatuurlijk.
Guest

Posted: Sun Oct 25, 2009 1:54 am Post subject: Oil in exhaust, Rotax 914

jason Parker wrote:

 	  Quote: 	
		   If the ball in your check valve doesn't make a good seal, it will

 fill up the turbo oil drain box due to gravity feed. When you go to

 start it, you will bleed oil past the turbo seal until the oil coming


	


I have reasons to believe that the oil was already past the seal before

I started the engine. In the months that the engine didn't run, oil has

seeped past the seal. Before the engine produced any significant heat,

the oil was already blown out the exhaust. While I agree that a constant

flow of oil in a very heat environment will coke up the wastegate, I

don't think that oil that is quickly thrown out of a cold engine once in

a few months will cause wastegate problems. In fact, the wastegate on my

914 feels still normal.



 	  Quote: 	
		   If your burning

 oil all the time then it is one of the following, your turbo needs to

 be rebuilt, your oil check valve is not poping at 65 psi and over

 supplying the turbo, or your secondary scavange pump isn't working

 properly.


	


I agree with that. I will thus carefully check that the engine is not

burning oil all the time. At the moment I can't start the engine because

I drained the tank (the prime reason I started the engine was that this

was the easiest way to get rid of the small amount of fuel that was left

 ). Next time (won't take months!) I will carefully monitor whether

oil is thrown out again.



Thanks for your comments,

Frans

litesellme(at)YAHOO.COM
Guest

Posted: Sun Oct 25, 2009 12:47 pm Post subject: Oil in exhaust, Rotax 914

I had a guy with a 30 hour engine blow his engine with the same reasoning. Yes, once you will up the oil drain box, it will seep past the seals. Turbos can't take any back pressure at all or they will leak. You can do the same thing with a new turbo. It is your check valve. replace the ball and the banjo bolt and you will be good.

 Jason



--- On Sun, 10/25/09, Frans Veldman <frans(at)paardnatuurlijk.nl> wrote:



  	  Quote: 	
		  

From: Frans Veldman <frans(at)paardnatuurlijk.nl>

Subject: Re: Oil in exhaust, Rotax 914

To: europa-list(at)matronics.com

Date: Sunday, October 25, 2009, 2:50 AM



 --> Europa-List message posted by: Frans Veldman <frans(at)paardnatuurlijk.nl (frans(at)paardnatuurlijk.nl)>



jason Parker wrote:

 	  Quote: 	
		   If the ball in your check valve doesn't make a good seal, it will

 fill up the turbo oil drain box due to gravity feed. When you go to

 start it, you will bleed oil past the turbo seal until the oil coming


	


I have reasons to believe that the oil was already past the seal before

I started the engine. In the months that the engine didn't run, oil has

seeped past the seal. Before the engine produced any significant heat,

the oil was already blown out the exhaust. While I agree that a constant

flow of oil in a very heat environment will coke up the wastegate, I

don't think that oil that is quickly thrown out of a cold engine once in

a few months will cause  wastegate problems. In fact, the wastegate on my

914 feels still normal.



 	  Quote: 	
		   If your burning

 oil all the time then it is one of the following, your turbo needs to

 be rebuilt, your oil check valve is not poping at 65 psi and over

 supplying the turbo, or your secondary scavange pump isn't working

 properly.


	


I agree with that. I will thus carefully check that the engine is not

burning oil all the time. At the moment I can't start the engine because

I drained the tank (the prime reason I started the engine was that this

was the easiest way to get rid of the small amount of fuel that was left

 ). Next time (won't take months!) I will carefully monitor whether

oil is thrown out ar?Europa-List" target=_blank>http://www.matronics.com/Navigator?Europa-Li   --> http://www.matronics.c===================





	


           [quote][b]

frans(at)paardnatuurlijk.
Guest

Posted: Sun Oct 25, 2009 1:26 pm Post subject: Oil in exhaust, Rotax 914

jason Parker wrote:

 	  Quote: 	
		   I had a guy with a 30 hour engine blow his engine with the same

 reasoning. Yes, once you will up the oil drain box, it will seep past

 the seals. Turbos can't take any back pressure at all or they will

 leak. You can do the same thing with a new turbo. It is your check

 valve. replace the ball and the banjo bolt and you will be good. 


	


Ok, I will replace these, shouldn't cost me a fortune. Thanks!



Frans

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