brettd

I adjusted the rockers like it said in the book but i think i might be wrong because when i turn the motor over and hold my thumb over the spark plug hole their is like no compression. Before i redid the valves it would pop my finger off when i turn it over can someone please help me out. is is a 1979 350 non roller.

Guest

You probably did do it wrong. Most of the time, people do the 'spin the pushrod' method and end up way too tight before they even tighten down the rocker. The idea is to take up the slack between the lifter, pushrod, rocker, and valve. You want it where there is no more gap from where the rocker is loose. Make sure you do not overtighten, sometimes the plunger in the lifter is easy to compress and if you arent careful you wont notice it.

As for where to have the engine, I have used methods in books a million times. Its usually not until you get to bigger cams that you have to be really **** about where the camshaft is in its rotation.

brettd

ok thanks so just do it as the book describes but dont tighten them as much? and when i tightened them to much did i make the valves stick open therefor not actually ever compressing the air inside the motor?

Guest

Yea, thats what would happen if they were too tight. Thats my guess.

What cam you have in there?

brettd

not sure on the exact grind specifics but it is nice. It is setup to be a blower/nitrous cam (not much overlap). it was turning 10.9s in my friend s camaro with a b&M 144 roots blower running 8lbs. It is a 79 350 with all forged internals and setup at 8.5 to 1 compression. I am getting it running with my tpi setup and then i am fabricating a twin turbo setup for it. I am just having some last minute bugs on the tpi to work out.

Vader

You almost can't miss when setting the valve lash on a hot, running engine.

The "spin the push rod" method can work, but in addition to spinning the push rods to check for clearance, you should also check the rocker lash (up and down) to verify the zero lash point. It can be a little tricky until you develop a feel for it.

You may also want to throw out the "book" specs on an aftermarket cam and only turn down the adjusting nuts an additional ¼-½ turn after the zero lash point to help prevent valve float from lifter pump-up at higher RPMs.

billyde

Help, I've got a 3rd gen z-28 but I just bought a 77 skybird today, I believe there is a site similiar to this for 2nd gens but I can't find it. I always come here for 3rd gen info. If you can help, thanks.
Billy D

brettd

thanks guys that was what was happening. I tighened the rocker arms down way to tight so the valves were sticking open and not shutting all the way = ). I adjusted them (it was messy but i did) and now i am rewarded by the nice lopey idle i wanted when i started this project = )