JK:

I have them on my Twin Beech and they make a lot of difference in the amount of oil which is blown out of the breather.  These are lose engines.  They work.  Are they worth it on a 470, 520 or 550 or any of the lycomings??  I don't know as I think that's a function of how healthy the engine is and how anal you are about oil on the belly!  <g>  Are they necessary?  Not on a healthy engine.

In a healthy engine, they are a nice way to keep the belly a lot cleaner.  They tend to cover up high crank case pressure from bad rings in an unhealthy engine.

Do they work as advertised?  In my expereince, yes.  Are they worth it?   It depends!

How's that for a non-commital answer? <g>

Walter Atkinson

Walter, Good answer..  What would happen, on a "conventional" vented engine, if the vent fumes were induced into the lower part of the exiting exhaust system??  Wouldn't that burn up the fumes and thus, eliminate the oily belly??  It is done on the T-63 turbine engine installed on the Bell 206.

Yes, if the oil return is vented into the exhaust, the extra oil vapor would get burned up--and would make NASTY exhaust stains anywhere it touched.

Walter Atkinson

Here's a smart man. He rips the rugs out once... she's gotta clean the belly forever?

Yeah, RIGHT.  Never met one yet who's that dumb.  <g>

You're gonna get the rugs ripped out and she's gonna think of a million reasons why she isn't going to clean the airplane--much less the belly.

We're guys.  We like to be TRICKED.  We're so good at it.

Walter

Barry,

Buy a gallon og WD-40 and a spray bottle, this will make your wife's job easier,...... when you start doing it  |

You can buy Gallon cans of WD-40 at Graingers

I buy mine at Lowes. I think the last time it was about 12 dollars a gallon.

At the risk of appearing badly (since this question wasn't directed at me), and also at the risk of appearing to be on Walter's case,...which I'm not... I must say that Walter's position in agreement with "jk" to vent the crankcase blow-by into the exhaust system is an exceedingly bad idea.  Such a mod would result in exhaust-gas pressurizing the crankcase via the vent/oil seperator plumbing, and would not only introduce corrosive exhaust to the crankcase, but would likely result in blown prop-shaft seals, etc., and may even result in the total loss of oil while inflight.
  Don't do it.
  (And Dow-Corning's bathroom cleaner, "Scrubbing Bubbles" does an amazing job of removing exhaust stains.  I learned that trick from one of the pilot's on the Red Baron's pizza demonstration team.  Check it on an inconspicuous place on your paint however.)

Thank you for clarifying your statement.  I'm glad we found something we agree on! ;Þ
  There is an excellent commercial product available that is the "bomb" on messy bellies,....Hydrosolve,...by JetStream.  I highly recommend it.  Easy to use, and that bad stuff just dissolves away!  (Safe for airplanes, too.)

<http://www.jetstreamproducts.com/>
Click on WetWash System, and view Hydrasolve  (sorry that I mis-spelled it earlier.)