Proform locking header bolts
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Teching In
Joined: Jun 2019
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Proform locking header bolts I’m in the process of installing LT on my 05 CTS-V. I ordered proform locking header bolts and the instructions say they need torqued to 28ft-lb Stock torque is 18ft-lb. 10 extra seems excessive it also says that vibration will tighten them so there is a chance it can increase even higher. I don’t want to end up in a situation where I’m snapping bolts trying to remove them. Has anyone used these before? I was thinking of splitting the difference and going to 23ft-lb but I’m nervous going heavy because of the aluminum heads. I can call proform tomorrow but it’s finally tolerable weather and comfortable in the shop I would like to just keep rocking and get this buttoned up.
From the website
Each PROFORM Grade 8 Header Bolt is permanently assembled with a pair of special washers. When the bolt is torqued to 28+ ft-lbs, the washers super-hardened external teeth bite into and grip the bottom of the bolt head and the top surface of the header. After being self-locked in this manner, any bolt-loosening rotation is blocked by a wedge-locking action created by the washers interfacing, matching cams. Its an uphill climb: vibration that might ordinarily loosen the bolt actually increases the wedge-locking tension, securing the bolt even more. Because this simple wedge-locking method uses tension instead of friction, contact with oil actually facilitates the wedge effect. When changing headers, PROFORM Header Bolts can be untightened with a normal wrench, lubricated, and reused.
From the website
Each PROFORM Grade 8 Header Bolt is permanently assembled with a pair of special washers. When the bolt is torqued to 28+ ft-lbs, the washers super-hardened external teeth bite into and grip the bottom of the bolt head and the top surface of the header. After being self-locked in this manner, any bolt-loosening rotation is blocked by a wedge-locking action created by the washers interfacing, matching cams. Its an uphill climb: vibration that might ordinarily loosen the bolt actually increases the wedge-locking tension, securing the bolt even more. Because this simple wedge-locking method uses tension instead of friction, contact with oil actually facilitates the wedge effect. When changing headers, PROFORM Header Bolts can be untightened with a normal wrench, lubricated, and reused.
