Hello all,  I am working through my annual and did the inspection as outlined in JSL 014-2.  It has you look for signs of overheating in Section 5.3.  I have had good compression and really no problems.  I have been flying for about 350 hours and the engine runs fine.  But I did have overheat signs near the exhaust valve.  See picI talked to Pete at Jabiru, and I decided to pull the heads and send them to him for inspection. Really was not very hard to remove the heads.  Just took my time and labled everything.  

I was kind of suprised by the amount of Lead deposits.  

I only have about 350 hours.  But I do run 100LL and do lots of short flights and lots of touch and gos.   

I was impressed that Jabiru got right to it and turned them around in a couple of days.  They got right back to me with the inspection the day after they arrived.

When Pete inspected them he reported that everyting looked good.  But with the build up what likely happened is that some deposits got stuck under the valve and then allowed some of the blow by.  Then after a while the deposits disipated under the valve and then sealed back up.  The valves looked ok but some of the exhaust valves had some corrosion. Decided to go ahead and have him replace the exhaust valves and clean everything up. Just got them back and they look good.  I am in the process of cleaning up the piston tops and putting it back together. 

The other thing he suggested was to use Phillips XC 20W-50 which has better properties for removing lead and to change the oil every 35 hours.  I already change the oil at about that interval.  He also suggested using Decalin as a fuel additive.  I am also planning on using Mogas about everyother tank.  Found an airport with a reliabile source close to us here in Wichita.   

Kind of suprised to do this after only 350 hours.   I think it would have continued to run fine for quire a while.  But it is nice to have the heads zeroed out.  This has been a good annual!

Cheers and Merry Christmas