"White Chalk" looking stain on underbelly

[Eraaen]

My new Rocket, after approx. 80hours has developed a white chalky looking stain on the underbelly.  It will clean off with some elbow grease.  I've asked my mechanics at the FBO if this is "normal".. I get a "yeah, maybe" answer.

 

I'm trying to fly by the book.  I usually end up totally flying by TIT temp and let the rest fall into place.  The prior owner set the JPI to alarm TIT at 1550.  I've been keeping it 1530-1540

 

I'm trying to fly conservatively.  Trying to max out engine time.  just now coming up on first annual but found a cracked turbo housing on my first oil change (ouch).

 

Having always been a renter who never really cared about cleaning before.. IS this normal?  Am I running to rich? To lean?

[MHemperly]

On the leaner side. This is pretty common. Find a conservative balance between cht-egt-tit. But your 1530/1540 seems good

[Hank]

Sounds like exhaust residue. Light gray is normal.

Cleaning is easier with Aero Cosmetics Wash-n-Wax; red for the belly, blue for all of the other metal. It leaves a slick finish behind to make the next cleaning easier. Love that stuff!

[Shadrach]

Should be more of a very light grey than white. This is what is typically left over when the mixture is set close to peak or leaner. Lead content is high, so be mindful when cleaning it.  

[Eraaen]

I suspected lean, I've never shown Rockets stated fuel flows, I don't lean at high power settings, but I'm pretty much getting the impression I probably shouldn't lean much at all above 30 on MPress.  Hank, I already ordered the red stuff.

[Shadrach]

I suspected lean, I've never shown Rockets stated fuel flows, I don't lean at high power settings, but I'm pretty much getting the impression I probably shouldn't lean much at all above 30 on MPress.  Hank, I already ordered the red stuff.

Pretty certain it can be done with that engine and is done by many pilots.  Stick with what makes you comfortable. 

[Yooper Rocketman]

My Rocket has always left a white residue on the bottom.  13 years and 1400 hours and it's a PIA to clean.  I run ROP, so it's not from running too lean.  I have always believed it was lead residue, with some exhaust residue in it.  I think it has to do with the way the exhaust pipe dumps into the slip stream.  Every 3-4 years I have to sand and repaint one of the bottom panels (never the same one) due to minor corrosion around the screw holes from the lead residue.  Clean it often and don't use anything like Simple Green, as if that hits bare metal it's as bad as the lead.

[Yooper Rocketman]

Just FYI, the cruise setting I've used on the plane since purchase is;  30" Manifold and 2300 RPM.  My fuel flow is 19 GPH.  I know others run them harder, but this setting, according to the Rocket Documents, puts me at about 67% to 68% power.  Just never felt confident I could run the engine out to 500 over TBO using 75% power it's whole life (only 220 hours to go).

[Piloto]

The white residue is a sign of a good running engine not burning oil. Mine is also white/yellowish. Worry when it becomes brown.

José

[aaronk25]

Mike busch has 2x TBO hours on his turbo continental (Google mike busch overhaul) he cruises right around 1650tit. Your not going to appreciably shorten the life of the components by cruising at 1650, but you will save 3gph.

At $4 per gallon x 3 that's $12 per hour that's $16,800 in 1400 hours (TBO). So you could replace the exhaust system a couple times with the savings.

It's easier on the exhaust valves to run lean and hotter than dirtier and richer.

Just a couple thoughts.

[Eraaen]

Thanks guys, makes me feel better.  I'll just clean more often!!!

[RocketAviator]

My Rocket does same thing have to clean it often... I always fly LOP.. thought it was due to lead. Interesting.