engine and drivetrain Head retorque: Necessary?

[Guest Anonymous]

I have about 1000 miles on my rebuilt '02 engine, and I'm windering if I should retorque the head. I've heard both yes and no from knowledgable people, so I'm a little unsure. Is there any consensus on this? And if so what is the right procedure? (loosen then retighten, tighten only, etc.)

TIA

Colin

[Guest Anonymous]

The current factory procedure is to start the engine and run the car until fully warm, then shut the engine off and torque the headbolts to torque angle 25% +-5%. The instructions may be different for different gasket manufacturers though, so if you still have the little card that should have come in the head gasket package, go with the instructions on there. The old instructions in the factory manuals say to retorque after 600 miles, but loosening and then retightening to the original specs.

Matt

Maximillian Importing

[Guest Anonymous]

tighen only. set your torque wrench to the correct setting (55 ft/lbs) and check torques. sometimes the head bolts lose some torque for various reasons.

[Guest Anonymous]

After breaking in my bone-stock motor for 1000 miles or so, it started to run/sound noticeable different. It turned out that my head bolts needed retorquing. 45,000 miles later they are still fine, so I chalked it up to the normal settling-in process.

Mike

[Guest Anonymous]

(nt)

[Guest Anonymous]

What you need to do torque angle measurements is a torque angle gauge, which is kind of like a protractor that attaches to a breaker bar. Generally the measurement is achieved by torquing the fastener to a specific lb-ft measurement with a standard torque wrench, then doing the final torque with the torque angle gauge. The torque angle measument is just a simple measument of the number of degress of rotation of the fastener (i.e. 1 complete turn would be a torque angle of 360*). Supposedly, torque angle is a more accurate method of measuring bolt stretch/tension since it removes friction as a variable, which is why BMW and other manufacturers are now using it for critical fasteners like head, rod and main bolts and studs.

HTH,

Matt