Setting Valve lash w/ intake installed

[CDog86]

As the title says just wondering what the best way is to set valve lash on a 98 vortec 350 (has roller lifters and cam) that has the intake installed already? Thank you in advance for all the help!

[Engineer]

That engine should have pedestal rockers. The rocker arm bolts just tighten down and torque to like 30~35 ft/lbs. No adjustments like the older engines.

[CDog86]

It doesn't though it is like the older

[LTZ C20]

Late 90's Vortec 350's have regular stamped steel rockers mounted on rocker studs. The rockers are not roller. Only the cam and lifters are OE roller. The LS engines are when they went to roller rockers, and even most of those are roller mount, not rolled tip or "full roller". I've had the intake and valve covers off of a number of late 90's 350s, including my 97 Silverado.

[Engineer]

Ok. I guess you adjust them the same way as all Chevy V8s before them. I have roller rockers from a Vortec 4.3L V6 that adjust to net lash. I thought the Vortec V8s were the same since they are essentially the same engine minus 2 cylinders. That's my bad.



Here is how GM says to do it: (I do my 454 this same way. It has a solid lifter cam and I have never had an issue with retaining .022" lash on my 454s cam.)



Turn the valve rocker arm nuts clockwise until all of the valve lash is removed.
Turn the crankshaft clockwise until the alignment mark on the crankshaft balancer is aligned with the notch in the engine front cover tab.
Look at the number 1 cylinder valves as the crankshaft balancer alignment mark approaches the notch in the engine front cover tab. If a valve moves as the alignment mark moves into position, the engine is in the number 6 firing position. If this happens, turn the crankshaft clockwise 1 revolution in order to reach the number 1 cylinder firing position.



With the engine in the number 1 firing position, adjust the exhaust valves for cylinders number 1, 3, 4, and 8 and the intake valves for cylinders number 1, 2, 5, and 7.
4.1. Turn the valve rocker arm nut counter clockwise until the valve lash is felt in the valve pushrod.

4.2. Turn the valve rocker arm nut clockwise until all the valve lash is removed.

Zero valve lash can be felt by moving the valve pushrod up and down between your thumb and forefinger until there is no more up and down movement of the valve push rod.

4.3. When all the valve lash is removed, then turn the valve rocker arm nut clockwise 1 additional turn (360 degrees). (I personally do 3/4 turn on hydraulic lifters -Eng)





Turn the crankshaft clockwise 1 revolution until the alignment mark on the crankshaft balancer is aligned with the notch in the engine front cover tab.



With the engine in the number 6 firing position, adjust the exhaust valves for cylinders number 2, 5, 6, and 7 and the intake valves for cylinders number 3, 4, 6, and 8.
6.1. Turn the valve rocker arm nut counter clockwise until the valve lash is felt in the valve pushrod.

6.2. Turn the valve rocker arm nut clockwise until all the valve lash is removed.

Zero valve lash can be felt by moving the valve pushrod up and down between your thumb and forefinger until there is no more up and down movement of the valve push rod.

6.3. When all the valve lash is removed, then turn the valve rocker arm nut clockwise 1 additional turn (360 degrees).

[CDog86]

Cool thank you that helps a lot! Is your V6 stock or where did you get it from?

[Engineer]

The 4.3L V6 I referenced is in our 1997 Blazer. 315,000+ on the original engine. It is my youngest son's college transportation. I did have to replace one of the roller lifters in it when I couldn't get it to pump up.