Top end rebuild, tuning issues

[SchreinerM]

Recently pulled the top end of the engine. Cracked heads, so the guy at the machine shop put some together for me (not Vortec heads).

Summary - 350/350, new heads, cleaned-up stock intake, rebuilt q-jet, HEI, new plugs gapped at .040", idle adjustment screws ~1.5 turns out, checked and rechecked firing order, pulled and plugged vacuum advance.

After learning my way through timing, it fires up. Using a timing light I'm showing ~30 degrees advance at 1,200 RPM. I let it warm up idling until the choke plate opens then...

Let out the idle adjustment screw - engine dies. If I tune back the advance (aiming for 4-8 per the Chevy manual) - engine dies. If I try to drop it in gear - engine dies.

What am I doing wrong. Is it possible the balancer is off relative to the timing marks?

Thanks in advance,
Matt

[powerbench]

are you checking the timing with the vac disconnected from the distributor and plugged off?

[redhead69]

Like you mentioned it is possible the timing mark is off.. check that. Advance the hell out of it to get you running.. If your able to drive it after advancing it tune by ear. Basically you want it as far advanced as possible and not "pinging" under load. Theres alot more to it than that but is some ideas to get you going..

[hvychve]

Dont always assume its a timing issue, If you are to verify balancer, pull #1 plug and turn engine until you feel pressure blow your finger, than I would slowly turn the engne by hand and either watching both valves one cylinder #1 to verify they are closed , and see where your mark lines up, you can get in the ball park with a screw drivier in the hole while slowly turning eng. (by hand) watching it to stop going up or down, agian all you are doing is finding total TDC (top dead center)

If you are sure you have a good balancer, make sure your dist. weights arent stuck open, remove rotor and look or move rotor back and fourth , you should feel a spring movement, or better yet, put a timing light on it and pull your vacuum advance (plug it ) at idle , note your timing, and now raise to about 2000 rpm, you should see the mark on balancer through your timing light move substantiallly (10-25 degree increase)
If I was ever in doubt of a pointer or balancer, I would vacuum time my engine, install a vacuum gauge and increase timing (clockwise) until maximum vacuum obtained and than back down about one inch. good starting point.
you say you just o/h carb. maybe your float level too high or too low, mixture at idle maybe too lean or rich, I doubt its too rich with only a turn and a half out from seated .
I usually see around three turns out .
I would set idle speed on a warm eng. and run each mix screw in til it stumbles than out til it stumbls , follow the same procedure for the other one, than after you got em close you can fine tune each one to smooth even further either in or out slightly..
what about valve too tight.
I usually adjust my valves with intake off, but you can do it several ways, tdc method or running method, if running method , there are oil slingers you can put on rockers to keep oil from spraying , I have seen many guys pull one valve cover at a time and start engine and back off rocker until they hear click and back down til it stops and about 1/4 to half turn more, and follow procedure for remainning fifteen.
there are many possibilities as you can see, its like calling up the dr and saying you have a tummy ache, what is wrong? its hard to diagnose over the phone, if you get my drift. good luck and keep all informed of your findings.

[SchreinerM]

A good friend stopped over yesterday to help out, and I must say I learned a lot.

First, trying to keep the budget down, I didn't pull the lifters. Pulled and cleaned all the rockers and pushrods though. I adjusted the rockers according to the manual which sites hydraulic lifters. My engine is obviously not original, and it turns out the lifters are mechanical.

Long story short, tightened the push rods according to hydraulic which left the valves open - no compression = no firing. Backed them all off to approperate lash, did a compression test (150 across the board), and fired it up.

Tuned to 10 degrees advanced for base timing.

Thanks for the input above. Love this forum.