Pinging/crackling sounds

[PDubs87Z28]

I got a 87 Z28 305 4bbl and everytime i jump on the gas it will make a pinging/crackling sound....i use 93 octane to not have this happen all the time....when i dump lucas "real" octane boost in, it won't make a peep. I was thinking timing but the timing is as close as we can get it to run as good as it is now. the engine has to last until i save up for my 350....so any tips would come in clutch.

[enRo]

Any specifics on the cracking/pinging sound? Does it throw your car a little bit when accelerating, or does it feel like your not getting anywhere when it cracks?

I had a popping noise when acceleration... twas the spark system...

[PDubs87Z28]

only under heavy acceleration.....i was thinking about a tune up today....it sounds like metal ratteling in a can. It doesn't do it under normal driving conditions just accelling off the line(little hard) and keeping it higher RPM. i think its getting too much air and i wanted to put a dual snorkel air cleaner on. I got an open element and its running alittle crappy

[Tru2Chevy]

First off, welcome to the club!

How long has it been since you've done plugs/wires/cap/rotor? That would be the first thing I did. The open element shouldn't have anything to do with it.

- Justin

[Fasterthanyou]

The only time an engine can get too much air is when you WANT to be slow, which in that case you have ultimate control... it's called the throttle :) .
Find your base timing and reset it to whatever was factory spec. You're too advanced right now which explains all of the engine damaging noises. It's called pre-ignition, NOT detonation, although pre-ignition can lead to detonation if you keep going at it.

[PDubs87Z28]

good to be apart of the f-body socitiy.
the kid before me that had the car did a tune up with accel wires-plugs....not too sure if he messed with the cap and rotor. I was ganna get down and dirty and do the whole thing BUT money is very tight. Just threw in a new interior. But definatly the next thing for me is a tune up and a trans service...just waiting for some $$$$

Does anyone know if an 85 or 86 Monte Carlo SS 5.0 H.O Rochester Carb is bigger(or more CFM) than the 305 stock rochester out of the Camaro..NOTE my car is not an H.O. If anyone knows that let me know! THANKS

[PDubs87Z28]

we can't get the timing set dead on factory specs. when at factory specs it will not run smooth (don't ask me why) I had two different mechanics mess with it and the same thing happened. its as close as it can be....just a few degrees off. But i think your right about the timing but i can't get it to factory specs. Any ideas?

[Fasterthanyou]

I got an idea, bring it to a mechanic that actually cares. Too often these "mechanics" just don't give a rats ass about something as old as a thirdgen. They'd rather make money :( .
First off, setting the base timing requires that you know that the balancer hasn't slipped. This requires pulling the #1 spark plug and using a small screw driver or coat hanger find TDC. Verify that the balancer mark and the indicator line up, if not, mark the new position with paint. Now unplug the tan bypass wire, start the car, set the base timing to factory, turn the engine off, plug tan wire back in and start her up. Verify with a timing light that you're getting computer controlled spark control (it'll move around with just moving the throttle slowely.) If it doesn't change and at like 2500rpm it spikes up then your ecm doesn't even have control over the SA and you might have a bad wire or ESC module.

[PDubs87Z28]

good point but the one guy was my friend from the gas station i worked at and he did it for free and the other guy was my pops friend with a shop that did it dirt cheat. I figured they had to know something but what you said sounds like a good idea....know of any mechanics that actually care to check it out?