In this Tech Tip, we show the proper way to adjust valves on a GM604. The tool used is called a Valve Lash Adjusting Tool by LSM Racing Products and can be found in our online store here: Valve Lash Adjusting Tool
Alright. This is just a quick video to show everybody how to adjust valves because probably the most common thing I see wrong is people setting their valves the wrong way. Obviously this motor is one that's going together not one that's in a car, so it's gonna be a little bit different but everybody will get the idea just by what I'm doing here. So first thing we want to do is turn the engine over until the exhaust valve just starts to open like so and then we're gonna... we've got a nice floppy intake rocker there. We're gonna screw it down with just our fingertips so we've got no slop and then we want to go three-quarters of a turn back it off about an eighth come in and adjust the set screw in the center and lock it down. That's your three quarters of a turn pre-load. Now when we go to the exhaust, we want to turn the motor over until the intake valve completely opens and then completely closes. Just as it hits the seat, we want to set the exhaust valve. We'll do the same thing-- three quarters of a turn, back off an eighth, come up on the center set screw, and lock it down. We're done. Basically, just remember set the intake valve as the exhaust valve just starts to open, set the exhaust valve after the intake opens completely and then closes and hits the seat And you've got it made.