Head torquing procedure

[Petros]

Hi all. After having so much trouble with my head gasket recent, which I never have before I thought I would get your opinions.

When I learn to turn wrenches on cars there was a standard procedure to retorque the head after 500 miles. Even when you bought a new car you were required to bring it back within 500 miles or your warrenty would be void. The dealer would change the oil, retorque the head and adjust the valves if necessary. Now this is done in the factory.

In the race shop where I worked we would test run each freash engine on the dynomometer and then retorque the head after the dyno run. We had o-ringed the block and used special gaskets.

But now I notice that even the service manul does not instruct you to do a retorque on a new head gasket. the fel-pro gasket I used even says right on it retorquing is not necessary. Since I once had a head gasket fail at about 600 miles because I did not retorque it (it was a 1960 datusun 1600 sports car), I always do it.

My procedure is to clean the bolts and holes, lightly grease the threads and washers, and torque in three steps to the speified torque. Then usually after first run and warm-up I retorque both the head and manifold gaskets. I break the bolt lose with a short back turn, and then torque each one in sequence. Then I also retorque at 500 or 600 miles.

But I am wondering if doing this with the modern gaskest is necessary or if I may even be doing it harm. I would not think so, but I thought I would see if any of you have different information.

[keith]

The 319 alloy most commonly used today wasn't around when your Datsun was made. Its really in the alloy more than in the head gasket material. I don't think it hurts to retorque unless you are using torque to yield bolts, which the Tercel doesn't.

Interestingly, the 319 alloy was pioneered in the Vega, and while it got a bad rap then, it's the most widely used alloy in car engines today.