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Took me 3 years to figure out I was torqueing cylinder head bolts wrong
I always just went by the manual's torque spec and called it done. But last month I had a cylinder base nut come loose on a test run, and a senior mechanic watched me torque the replacement. He said 'you gotta lubricate those threads first' - turns out dry torque vs lubricated torque can be 20% different. Ever since I started oiling the threads and going by the wet torque spec, not a single re-torque has moved. Anyone else get caught by dry torque specs on critical fasteners?
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richardfox20d ago
Man I learned that the hard way on a timing cover bolt too.
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jesse8420d ago
Picking up on what you said about the torque difference, but I think the timing cover bolt is a special case. Most timing covers use a rubber gasket or sealant that squishes out when you tighten it, and that gives you a false torque reading too. You're supposed to let the sealant cure a bit first or use a wet torque spec that accounts for the lubricant properties of the sealant itself. A lot of guys just run them down dry and end up with leaks because the sealant hasn't set right and the bolt feels tight but isn't actually clamping evenly.
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