Oil in the induction system.. Ideas?!

[lr172]

Originally Posted by SegevFly

Hi All,

Firstly - thank you for your time looking into my engine issues.

The engine is installed in a Pitts S1S and is a vertical intake. Therefore no sniffer valve, nevertheless, the oil just simply run out of the throttle body, then into the floor via a small drain hole which is located in our air intake.

Based on the comments and suggestions provided, I am going to try and locate another sump, install it on our aircraft and fly to identify if it is the issue, if it does, I will get a new one from Superior or Lycoming

While perhaps costly, I am unable to determine what the oil is coming from otherwise..


I attached some additional pictures for your information, and I promise to let you know how I go!

https://ibb.co/syt2KgJ

https://ibb.co/mHH9Vkz

https://ibb.co/CQ8JjHs

https://ibb.co/nwQ9Xqy

https://ibb.co/hBvxC0c

https://ibb.co/jwgmRH1


Thank you again,

I would check each drain back line from the rocker boxes. A plugged line will allow excess oil to accumulate in the rocker box and if / when the level gets up to the intake valve guide, will leak into the intake runners. Pull them quickly after a long engine run and it will be obvious if you have a plugged line. This type of problem would only creating dripping on the floor after long runs and not after short runs. You also want to pull each intake tube and check for wet oil. You want to know which cylinder (possibly multiple) is the source.

Clearly a casting crack could cause this. However, it is a tough diagnostic exercise to start with and seems less likely with a sump that has not leaked for many years. If you find a wet intake tube, you can eliminate the sump as the culprit, so would start there.

Larry

[SegevFly]

Hi Guys,

Firstly - I would like to thank you all for your input and ideas with our issue - this community is awesome!


I am absolutely excited to update you that the issue was found - it was the oil sump!

While no cracks were found, the material (sand casting by Lycoming) was simple porose and allow oil to get into the air induction! Perhaps not a surprise when you think about the fact this engine part is 47 years old!

I ended up purchase a new oil sump from Superior and been flying ever since with no issue or oil in the system. Only the clear fuel it always should have.


I hope this will help someone one day.


Thanks again and happy flying,
Ido

[rv8ch]

Originally Posted by SegevFly

... I ended up purchase a new oil sump from Superior and been flying ever since with no issue or oil in the system. Only the clear fuel it always should have. ...

Glad you found the root cause and a solution. Don't forget to install a sniffle valve!

http://www.vansairforce.com/communit...d.php?t=178538