Possibly only in the book I carry around in my head - based more on working on automobile engines than on airplanes. There's no question to me that oil changes torque value results - and there's no question that a little 30w on the bolt threads will probably do more good than harm.

Do you know why the factory changed the torque value from 72 to 80 lb-ft on head bolts for most of the engines in the '80s? I don't, but they blew a lot of head gaskets and something tells me that the factory guys thought the solution might be to make certain there was enough clamping force.

Here's an opened package of factory head bolts. Take a close look. The envelope has discolored from..... oil. The label inside the package has discolored and become shiny from.... oil. I wiped the bolts on the paper towel and found.... oil residue. Nowhere in the FSM do I see instructions to clean the oil from the bolts before installing and torquing to value:



Whenever I've rebuilt a 3.0L engine, I've found baked oil residue in the deck hole threads. Unless it drained around the threads, that oil came from factory procedures.



In all my years of engineering study and practical experience, one thing I learned was that field mechanics sometimes learn things through the experience of fixing engineering mistakes.



It's not that the bolts are too long, it's that the hole isn't deep enough..... <img src="/forums/images/graemlins/wink.gif" alt="" />

Build a few 3.0L engines without checking - particularly those with cut decks and heads - and see how the head gasket holds up around #4 cylinder.

Frank