Stringing
 

Has anyone heard of using #2 permatex and a silk thread between case halves. I was curious because this is used on small aircraft engines.

That system is used on aircraft engines that machining is less precise to get a seal. The 911 case, just dope it and close it and you have seal.
Bruce

Silk thread
 

Very old technology, I built aircraft engines for many years and used silk thread and hylomar, It worked fine on Lycoming/Continentals, I have done 911 engines full time for 30 years and have tried many sealers, each has its benefits. Threebond has great product line that is my choice, 1211 and 1194 are the ones I use most.

Mike Bruns JBRacing.com

Here is the mating surface on an old C65 case. Now you know whey they use the silk thread!

http://i30.photobucket.com/albums/c3...1/100_7954.jpg

My thought was after I opened an A-65 for overhaul that had not leaked in 50 years it must work. I take it that there is no leak problems at the case halves on the 911 engine.

Try this link:

http://forums.pelicanparts.com/911-engine-rebuilding-forum/284737-complete-engine-sealant-thread.html?highlight=engine+sealant