this might be a silly question and I couldnt even find anyone else asking anything similar to this. what im hoping is the title is the silliest thing you've ever heard.

I just installed a refreshed 350 in my Z28. i was overheating due to cracked head so i decided to do a quick and dirty rebuild and use my buddy's old "built" 601 heads for a HO305. i know what you're thinking. but i spent a very long while calculating SCR and DCR with the cam im using(XE274 12-246-3) and I used a grinder to unshroud the valves and open and smooth out the bowls, cc-ing to be 58CCs when done.

thats 9.6:1 SCR and 8.19 DCR

break in went well with new converter and a small inputshaft leak. and setting the timing to 14BTC and 28 BTC total all in at 2800

honestly ive never heard PING before and i knew it would be some thing to look out for but for some reason im getting that "tiny metal ticking around" sounds only when in gear at idle and light acceleration. i can rev it up all i want in park/neutral no problem. the tranny doesnt have a long life expectancy so im hoping that is the noise but idk...

edit new bosshog conveter for cam

yes im running premium and later today im going to the next town over to try that rocketbrand from citgo 101 octane but not looking forward to 7 bucks a gallon.

any help or thoughts is much appreciated!

 

forgot to add that I assumed PING from timing and brought base timing all the way back to 8 deg BTC base timing and no change. it definitely likes more base timing tho

 

ping is caused by pre-detonation and the conditions leading to this are most prevalent when cylinder pressures are high and the mixture is lean, so light cruise with throttle tip in is where you'll notice it. proper egr operation will help.

without knowing your induction system or spark control it's going to be difficult for anyone here to provide a route towards alleviating it. But the conditions under which you experience it are common.

 

no egr or anything extra. just a 600CFM holley (2 jets bigger than stock in it) Edlebrock performer eps and a regular GM-HEI, port matched intake and mid length headers.

i see what you mean about cylinder pressures being high but why does shifting from park to drive with no throttle change make it start pinging? your thinking i need to fatten up the AFR?

 

If it's doing it in gear at idle , and your idle speed is set properly , then I don't believe it's actual pinging , and more likely something rattling like part of the exhaust or something similar ...

 

28 is pretty low on timing. Doesn't sound like detonation to me. Even most iron heads are going to run 30+ degrees on a SBC.

Could be mechanical noise.

GD

 

thats what im hoping. but i cant find anyting that could be the cause. it drives fine i suppose. obviously would be better with more timing but i worried about giving it more due the pinging sound. couple friends heard it earlier and said it does sound like ping.. I also looked up a video on what PING sounds like and its the same sound

 

Well - put some C16 leaded in it and if you still hear it then it's not detonation.

GD