been some time since I worked on the valve train of a motor. I am adding roller rockers and guide plated to a F-Body LS1. Some questions. Will the stock valve cover bolts be long enough to use adding a 1/2 inch spacer? How much pre load on the stock lifters? I read 1/4 to 1 turn but another guy said 1.5 turns. Finding TDC. If I watch the exhaust valve close and the intake open and close, at that point, If I rotate the motor another 180 degrees, should I be at TDC? Thanks

 

I don't know why you need to find TDC, but if its to adjust the rockers, you do the intake rocker when the exhaust valve starts to open, and the exhaust rocker when the intake passes full lift and starts to close again.

 

Pre-load should be roughly sixty thousands (0.060"). Tighten the rocker to zero lash. Then, setup a dial indicator to find how many turns that is on your motor.

 

Thanks guys.

 

What brand of rockers, if they are the Cranes the above is not correct as they are fully adjustable and also have a different thread pitch.

 

They are comp cams individual adjustable with guide plates. Let me know.

 

1/2" spacer you will need longer bolts, but they should have been provided in spacer kit. i'm sure the comp rockers call for 1.5-2.0 full turns pass zero lash. that puts preload in the .080-.110 range. stock preload is around .060-.070 i think.