The International Cessna 170 Association

I’ve been using TCP for years for my 0-300C and believe it helps to keep my plugs clean. I tried to order some from Aircraft Spruce and they are out of stock. So is everyone else on the internet, it seems. What’s going on? Has anyone tried Decalin Runup? It’s supposed to do the same thing as TCP but is 20% cheaper….and available!

I met personally with the CEO of Alcor about 15 years ago and it was a disappointment to find that their actual focus is instrumentation and sensors for military and NASA…not GA and Alcor-TCP. The recipe for TCP is proprietary and requires a specific certified-concoction of Toluene that is sometimes difficult to obtain (according to the CEO)….and that leads to product shortages.

I have tried Decalin and cannot tell the difference in results….but, I also talked to Decalin and they were less than convincing that their recipe does not contain a form of alcohol….something I do not want in my fuel system (and neither does Cessna…see the first sentence in the Type Certificate.)

AvGas includes a bromide …a scavenging agent….designed to reduce lead-fouling if the engine is aggressively leaned to bring EGTs up to 1100+…(the same temp TCP also requires)….and for the last decade that is what I’ve done and have suffered no lead-fouling problems. (I never use mogas….which some folks use to avoid lead.)