If the ball in your check valve doesn't make a good seal, it will fill up t
he turbo oil drain box due to gravity feed. When you go to start it, you wi
ll bleed oil past the turbo seal until the oil coming in equals the oil bei
ng 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, thi
s 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 boos
t spiked to over 28PSI due to this problem and turbo control issues. If you
r burning oil all the time then it is one of the following, your turbo need
s to be rebuilt, your oil check valve is not poping at 65 psi and over supp
lying the turbo, or your secondary scavange pump isn't working properly.
Jason
--- On Sat, 10/24/09, Europa <europa@pstewart.f2s.com> wrote:
From: Europa <europa@pstewart.f2s.com>
Subject: Re: Europa-List: Oil in exhaust, Rotax 914
Date: Saturday, October 24, 2009, 3:37 PM
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 91
4
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@paardnatuurlijk.nl> wrote:
l>
>
> 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
>
>
>
>
>
>
le, List Admin.
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