Loctite 515 for case sealant

[rocketbob]

My opinion and materials used have evolved over time. The rigidity has to be at the main bearings and thru stud surfaces, which get no sealant. Many of the engines I've used POB4/silk thread now seep. I use Hylomar mostly now but I've used Proseal and Permatex ultra black on Lycomings. In the past year I used Hylomar on a Lycoming, a VW transmission, and Porsche M96 and it works great.

[664781]

We use Hylomar on the big engine gearboxes here at work (DAL). They have finished flanges and have a lot more heat and time on them then we will ever see on our fun machines. No leaks after 10 or 20 thousand hours.

[Joe Jet]

Speaking of case halve assembly, when you guys get to the cylinder installation, are you lubing the through stud threads and the deck stud threads, or just the through stud threads? J