TR6 Retorque Opinions on a Rebuilt TR-6 Motor

[Mark_Gibson]

I was wondering what the popular opinion is for retorqueing the head on a newly rebuilt motor. I've heard anything from 15 minutes of run time to a few hunded miles before retorque and readjusting the valves. I went to 75 ft/lbs on all the head bolts initially; the range is 60 to 80. Thoughts?

Thanks,

Mark
1970 TR-6

 

[vettedog72]

Mark:
Philosophically, I think the heating and cool off of the engine has some corresponding expansion and contraction of the metal , block, head., bolts/studs and gaskets. The re-torque would help with any adjustments that may be needed because of the expansio9ns and contractions. Maintenance books frequently state wither the head should be re-torqued or not after a rebuild. I do not know what the TR6 factory book states. Now that I write about this, I don’t see the difference between a factory new engine and one that has been rebuilt? Not many cars get a re-torque included or excluded in the warranty. I would not re-torque if the mfg stated as much in the maintenance manuals. Maybe both of us will get an education out of your question.

 

[Webb Sledge]

Retorque the head to 70-75 lb/ft at 500 miles. This was the procedure givin to me with my new engine. The guy who helped me build it has built about 10 TR6 engines, and goes by that rule everytime. (Incidentally, he also owns the Triumph restoration shop that I work at, so I think he knows what he's talking about). As vettedog stated, part of the reason for retorquing the head is because of the expansion and contraction of metal as it's driven, but it's also because the studs actually stretch over time, causing some of the torque to come off. That's why you when you first torque a head, you do that pattern, then go back over it again. The second time you do it, you'll always have to tighten the bolts up a little because the studs have stretched.