Thanks, guys.
Just so I understand, you mean you checked them and they were still at proper torque, or you never checked them? (I found in the owner's manual where they say to retorque after 10-20 hrs.) From what I've read it sounds like maybe the base gasket can shrink in thickness after break-in/cook-in enough to change how far the bolts are stretched/strained, but after you retorque them, supposedly they're good thereafter...?
Just trying to do it by the book here. Don't want to give the saw any excuse to fail.
Some I've checked, others run em till they die, rebuild+repeat.
Only had one saw where the cylinder gasket was the culprit for it dying, and I inherited it that way, one bolt was out and wedged into a cooling fin...
Far as proper torque? go until the wrench flexes... hasn't failed me yet. (note this only works on Allen type wrenches and T handle Torqs wrenches, if you can flex a 7/8 box end wrench without breaking a bolt...)
Yer also sorta half right with the heating cooling aspect, but its mostly a matter of the bolt getting its stretches in, the gaskets are metal, and not likely to move much, but the bolts have multiple planes on which they can move, both from vibration and heat stresses.
To be clear, I've never personally blown up a saw (I mostly run em over), I've loaned em out and had them get roached (hot saws and dull chains are a bad combo), and I get a bunch of dead saws and make them go again from time to time... I get bored, and antsy, cheaper then a drug addiction and legal too.
If yer saw is suckin air where its not supposed to it will be a bitch to tune, and continually get worse until it leans out far enough and burns up. A competent shop with a vacuum tester can check em in about 10 minutes, a used saw will generally have one or the other crank seals go bad, also an easy fix with the right tools...
A new saw if its leaking could be anywhere, and likely expensive.