Im going to be putting a set of 1.7 roller rockers in this weekend this is going to be the first time I did it so could someone give me a rundown on how to do it? Do you just take the old ones off and torque the new ones down?
Thanks
Tom
Tom - go to www.cranecams.com and download their instructions. No, you can't just take the old ones off and torque the new ones on. Each pair you install must have the valves closed during the install. The way I do this is rotate the engine by hand (clockwise) til that pair of valves are closed - watch the exhaust open/close, the intake will open as the exhaust is closing - once the intake closes, both are closed and you're ready to remove/install that pair. Follow the firing order, and the next pair in the order (1-3-7, etc.) will require very little engine rotation to have them closed and ready for swapping.
Unbolt the old ones, remove them. Install the new ones, hand tighten the bolt until there is zero lash (no gap on pushrod or valve stem end). Once you're at zero lash, put your torque wrench on it and torque to 18-20 ft-lbs while counting the number of turns it takes to get there. It should hit the specified torque in 1/4 to 1 turn. If it takes more than 1 turn, use a shim under that rocker to reduce the number of turns to the spec'd torque. One .030" shim reduces the number of turns by approximately 1/4. If it takes less than 1/4 turn to reach the spec'd torque, or if you can't reach zero lash at all even after they're tightened, you'll either need slightly longer pushrods, or you'll need to remove material evenly from the bottom of the rocker trunion. This shouldn't be an issue unless the heads/block have had some machining done on them at some point.