Engine Knock

I'm having issues.... I'm running a 289 bored .030 over with about 9.0 to 9.5 to 1 compression... Mallory 6AL ignition module, edlebrock 600 cfm carb, etc. I've been running 89 octane gas for awhile was doing alright then I started knocking i've tried adjusting the timing up and down, tried adjusting the carb... to no avail... what else can I do? NEED help. thanks

 

91 octane

If it just started knocking when the weather warmed up just change to 91 for the summer. Or put in more cooling.

 

did we recently change to the crap gas for the summer? if so jump to the higher octane and see if that cures it or try some of the octane booster available at checkers or pep boys.

 

is it a knock or a ping? is it near the head or in the pan? dont forget the factory recommended octane was 92 minnimum. hope its just the fuel

 

Well, I did try octane boost which I think should have pushed the rating well into aceptible ranges and it still pings... it's detonation btw, sometimes it'll be fine but the majority it'll ping, I need to put a timing light on it soon to find a baseline again,

 

Hey is it posible that my distributor's vacume advance might be messed up? well it seems that no matter what I do with the initial timing or air/fuel rods/springs makes a significant differance with the pinging it just goes from bad to worse and sometimes back to bad... but it always gets worse at half or just over half throttle though full throttle it stops or atleast I can't hear it anymore and at low to moderate cruise... any ideas would be appreciated, thanks.

 

check the advance while revving and see if it goes past 38 degrees. that will help eliminate that.

 

with or without the vacume hooked up?

 

sorry, yeah with it hooked up. it probably wont go past that without the vac, but if the diaphram is worn or not set correctly it will go past that. efi engines can run past that but old carb289 shouldnt.

 

with the vacume unpluged and the timing set to 11 degrees advanced and then plugging in the vacume it immediately jumps to 28 or so degrees and goes up from there when I rev it 30 .... 40... is that normal? unpluged I set it to 11 and can rev it up to 30 to 40 with almost full throttle. pluged starts at around 28 and goes up from there with little effort.

 

either way as you open the throttle the timing will advance. you want it to stop around 38.doesnt sound like that is the issue though. try setting your initial timing around 5 or 6 and go from there.

edit: check the wires and cap for a short.