Ping ping ping ping WTH am I doing wrong!

[Thomas Fournier]

Ok I have a 350 SBC, bored 20 over eagle rods and balanced, 68cc performance iron heads w/ ARP studs edelbrock intake, crower beast cam full roller comp iron rockers, Sean Murphy quadrajet, Chevy H.E.I. w/ Accel coil and module w/ msd cap and rotor w/a recurve kit for 32 degree advance at 3200rpm. It pings like crazy even just light throttle. What am I doing wrong. It's set at 8 degrees primary and even w/the vacuum advance not hooked up it still pings. Yes it's on premium shell 91 octane. And the engine was built by a local reputable shop. Any input would be great cause I'm starting to just give up!

Thanks,
-Daniel

 

[tRustyK5]

retard the timing...

 

[ChrisPerry]

Confirm the timing marks are correct using a piston stop.

 

[Joe In Montana]

Ok I have a 350 SBC, bored 20 over eagle rods and balanced, 68cc performance iron heads w/ ARP studs edelbrock intake, crower beast cam full roller comp iron rockers, Sean Murphy quadrajet, Chevy H.E.I. w/ Accel coil and module w/ msd cap and rotor w/a recurve kit for 32 degree advance at 3200rpm. It pings like crazy even just light throttle. What am I doing wrong. It's set at 8 degrees primary and even w/the vacuum advance not hooked up it still pings. Yes it's on premium shell 91 octane. And the engine was built by a local reputable shop. Any input would be great cause I'm starting to just give up!

Thanks,
-Daniel

Causes for 'pinging' --->

• Lean fuel mixture. [also lack of- or short- accelerator pump adjustment or action; low float level, no emulsion tubes (carbs)].
• Over advanced timing - [you state it's not your problem].
  
• Vacuum leaks - [usually worse at idle or 'tip-off' though].
• Supercharger pop off set at 65# [or higher].
• Over advanced cam - [did someone misinterpret the cam gear timing marks?].
  
• Compression too high. [Pistons with high domes and an intrusion design, small cc heads, etc.]
• Marbles in the combustion chamber(s)
  
• Lack of EGR - [which cools the charge and prevents knocking/pinging].
  
• Wrong heat range spark plugs - [are you using Champions? I dislike them intensely].
• Low octane [I included this although you state it's NOT your problem].
  
• Low coolant level; wrong thermostat [not likely these days - I use a 200F for my '86 383 stroker].
  
• Bad/defective/missing/poorly working fan clutch or electric fan(s).
• Low altitude - [carbs are not usually computer/mixture controlled for changes in altitude].
• Intake valve(s) adjusted too tight and holding the valve slightly open all the time..

I know that if I take my 6000 foot altitude engines to sea level - they ping and knock badly.
If you left any of the computer in the system still, it should 'hear' the engine ping and start retarding the timing..

 

[black dawg]

Do you know compression ratio?
cranking psi?
cam profile?

 

[1-ton]

Connect vacuum gauge to manifold vacuum, then turn distributor to max vacuum inch...then back off 1-inch, and test drive. make sure the distributor is hooked up to manifold vacuum and not port vacuum.