Valve adjustment sequence?

Topic: Valve adjustment sequence? (Read 1732 times) previous topic - next topic

Valve adjustment sequence?

January 08, 2016, 01:37:19 AM

Hey guys,

I am getting closer and closer to getting my T-Bird back on the road. According to the service manual,the first of two steps for setting the valves is to rotate the engine over so that each lifter is sitting on the small circle of the cam lobe (side opposite of the peak). For me this involves trying to turn the engine over turning the crank pulley and trying to look at each lifter. It seems like there's got to be an easier way. My question: how many of you guys still running the 3.8 actually go through the two step procedure, or just tighten them all down? I'm not 100% sure why the first step exists.

Thanks

Valve adjustment sequence?

Reply #1 – January 08, 2016, 02:25:08 AM

In a nut shell, while the lifter is on the base of the lobe, it's basically not under load. You will be setting "lifter pre-load". You have to set the adjust then otherwise the lifter would be collapsed to far and not able to do it's other job of oiling the top end and it would be making a horrible noise and not run very well.

Valve adjustment sequence?

Reply #2 – January 08, 2016, 11:42:30 AM

If it has bolt down rockers only adjustment is just that "bolt them down"...

Above said, aftermarket bolt down rockers are usually supplied with shims that can be placed under the stands to bring preload into spec if necessary... If going that route lifter must be on base of cam...

Valve adjustment sequence?

Reply #3 – January 08, 2016, 04:27:41 PM

Thank you,

I do have one question: why does the factory service manual have the two step process then? I will agree, just bolting them down seems easier.

Valve adjustment sequence?

Reply #4 – January 09, 2016, 07:43:40 PM

Tightening rocker bolt when on cam lobe doesn't really make a difference, I've done it both ways without issue... If on base of cam that lifter will soon be on lobe when you rotate the engine for the next one(s)...

If you're adjusting valves on a Hi-Po engine with 300Lb spring pressure when open, no not a good idea...