Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
So my Daughters fiance has a 1979 Corvette with an L82 350, That he ran with out oil and it through a bearing. He had the block rebuilt and then installed the heads, And timing chain. And put it back in the car. So he asked me to take a look when it would not start. Been a while since I worked on a car with out a computer. So really having to think this through. Timing marks do not line up but I can get it started and idle it around 1500 RPM, Vacuum is only around 13 to 14. It makes me think timing is off from a timeing chain perspective. I can move the destributor and it drops vacuum to 10 or move it the other way and it drops it to 10, if I get distributor in the right spot it idles well at 1500 RPM. And runs pretty smooth. If I start adjusting idle down vacuum drops quickly.
I remember timing engines with a vaccum gauge and usually on the 350s I should get between 15 and 17. I do have a timing light but it seems that the timing marks do not match up where they should be. But it is running. I have never seen one with timing marks this far off.
So my next steps
Pull #1 Plug
Bring it to TDC
Confirm TDC using Distributor\Rotor
Timeing mark
And camera
If timing marks and Rotor Line up
Then smoke cylinder 1 to see if I have a leak at TDC?
Are the secondary's stuck open a bit in the carb.? And it's possible that the balancer spun on it's rubber, giving you a bad timing mark, take the balancer bolt out, the keyway should be pointing centerline of cylinder one
Just remembered too,it's possible the lifters pumped up a bit and the valves are not closing properly, pop off a valve cover,check online for which valves to adjust at 0 and 180,no matter where it's at when cover is off,you should be able to spin a pushrod here or there, otherwise they are ajusted too tight
Was the camshaft replaced as well? does the needle bounce or stay steady? How were the valves adjusted? Are the all the vacuum hoses hooked up? Right carb gasket ? Throttle cable stuck partially open?
Found we were off a tooth when they put the distributor in. So have it idling at 800 rpm now sounds pretty good. Has a little more roughness then I expected. And Vaccuum is still way lower then I expected. We sit about 8-10 and gauges bounces a bit.
Thinking it may just be valves seating. Since it sat for 4-6 months after they put the engine in.
So now that I have timing pretty close it bounces alot at idle. I have sprayed starter fuel around carb and intake. It actually runs a bit better with a vacuum leak. I have closed all vacuum ports to test as well.
Topic Author
