VERY low ime 912 ULS - leaking exhaust valve

Hey Roger,

I know you are right and many people use it with good results. In fact, I have seen almost zero problems reported. Decalin converts the lead in the combustion chamber to lead phosphate, which is less sticky and crumbles more easily than the lead oxide you get without it. But you do get more product expelled out the exhaust valve and into the exhaust. The lead phosphate is supposed to be easily crumbled and knocked off the valve stem and valve seat by the normal action of the valve. I just wonder if now and then... it isn't.

When this happened to my friends 914, I found a couple documents indicating TCP lead scavenging fuel additives were not recommended for turbocharged engines. I thought at the time this was likely because the lead phosphate in the exhaust might cause problems in the turbo charger and wastegate. I don't see that limitation on any Decalin Runup literature now, but I would be curious about their specific opinion regarding turbochargers. 

I forgot to mention that Brad mentioned that they are increasingly seeing issues with the quality of car gas and that particularly gas containing ethanol deterioriertes rather quickly.

100LL + Decalin is therefore also what he recommends, despite of a possible deposit build up, particularly if the aircraft is flown irregularly, like ours.

Here in Southeast Michigan, all the ethanol free gras is less than the required 91 Octane, that's why we are using 100LL + Decalin.