White Tipped Spark Plugs

[MooneyMunnerlyn]

Hello,

Not directly Mooney related but this is a great place to ask. In addition to our Mooney E we have a Beechcraft A36. On the A36 we just got a brand new overhauled Continental IO-550 naturally aspirated and overhauled by Triad. The mechanic that put the motor on had the fuel settings way too lean. It was burning 21GPH full rich at takeoff instead of around the normal 31GPH or so. The old crappy stock baffling was never replaced so it was “test ran” by their shop for 8 hours and the CHTs would reach right around 450°F according to the Garmin engine data.
When we took delivery of it, we had the same issue but we are not A36 savvy yet so we didn’t know it was set too lean overall because it still ran seemingly okay but would run super hot. Another issue is that the mechanic left the engine data in Celsius because he says it’s what the book says to do. Albeit not a great excuse to deliver an A36 to us where we can’t read our engine monitoring data. That’s why we knew it was hot but couldn’t read exact numbers right away in flight without calculating. 
 

Within the first 15 or so hours of the engine the rocket cover gaskets melted too and were leaking oil. 
 

After annualing the airplane, we fixed the fuel issues, compressions are seemingly fine, but one tell tale sign of overheating that we found was that every spark plug had a huge white ring around the tip and I’ll attach a photo. We haven’t borescoped the cylinders yet to look at the valves but I’m very worried about this engine. I worry that while issues might not be showing their self immediately, we might find some bad ones in the coming hours. 
 

What are some of y’all’s thoughts on this situation? What else can I do and what would be your recourse? 
We haven’t ruled out asking for a new engine since this one has been ran very hard and very hot ever since its first hour. 

Edited February 15 by MooneyMunnerlyn

[Schllc]

My guess is just lead deposits. Looks like someone left those in for a lot longer than typical. 

[MooneyMunnerlyn]

4 minutes ago, Schllc said:

My guess is just lead deposits. Looks like someone left those in for a lot longer than typical. 

Spark Plugs only have 59 hours and were new with the engine. Engine was running so lean there was hardly any lead down in the barrel where it would normally collect. 

[Fritz1]

what is redline CHT on that engine? what do valve faces look like? if engine was delivered with fuel flow so low that redline CHT was exceeded this may have damaged the engine and you may have a recourse against the shop, lawyers will chime in, do you still have a primary that reads CHT in F? if yes, what max did that read? the $80,000 question is whether that engine is damaged or not and how to determine this right now, engine guys will chime in, I would call a couple of engine shops and ask them off the record on the phone 

[N201MKTurbo]

It looks like deposits from a very lean engine. Now that it is set up right, I would clean them and run them for a few hours and have another look.

[Shadrach]

The plugs do not look worn at all to me. By “white tipped”, I guessing that you’re referring to the white band around the threads closest to the electrode. Does it come off?  Clean and reinstall.
 

By my rough calculations that engine has been run just slightly ROP at full power since it was overhauled. I would definitely start with a borescope. The plugs should be fine.

31gph is a bit rich. 29.5gph full power, full rich is the ideal.

[PT20J]

My POH for an A36 with an NA IO-550 shows that the factory gauges for oil temperature and CHT are in Celsius, so your mechanic was correct to set the engine monitor that way if it is the primary engine instrument. The POH lists a maximum CHT of 238 deg C which is 460 deg F. So, it was close to redline. But, did it fly, or run for 8 hours on the ground? Was it near redline the whole time, or just part of the time? I would want to know the details of how it was treated for break in. Also, you apparently ran it for another 7 hours and got it hot enough to melt the rocker cover gaskets. So, what was the maximum CHT during the time you ran it?

If it were mine and borescope looks good, and compression looks good and the oil filter is clean, I'd just clean the plugs, get the baffling fixed and fly it and watch it carefully. These things are pretty tough and it didn't get over 500 deg (at which point George Braly has said that the cylinder is usually toast) and apparently there is no sign of detonation due to lean mixture and high CHT. It's probably fine.

If you are worried about it, send the engine monitor data and borescope pictures to the overhauler and get their recommendation. You'd probably have difficultly making a claim against the installer at this point because it would be difficult to prove whether any damage came during the run in or your subsequent operation.

[cliffy]

Saavy Aviation specializes in reading downloaded engine data. Give them a call

I'm NOT related to them in any way they just know stuff.