I've done just about every thing that I can think of to get rid of the pinging i'm getting except turn down my spark advance below 10* initial. I'm still getting pinging although now it's pinging at high RPM in first gear, evan more in second gear, and I don't evan want to see what it's doing in third gear. Does any one have any ideas? What else can I try? I have a new carb and I think that it may solve my problems but I don't want to make a $500 guess. Any comments?
Jason, What plugs are you running? They could be too hot or too cold. Also, what distributor are you running. There is a bushing that limits spark advance that frequently goes missing. Could also be too quick of a mechanical advance for the gearing of the car. Give us a few more specifics and we'll try and help:TU:
Got Gas I had a ping in my last car. All I ended up doing is running 4 full tanks of BP Super 93 and a bottle of NOS octain boster in each tank. I had it for almost a year after that and never heard the sound agein. It's worth a try.
Larry I'm running a stock dis. with a pertronix module. I removed the bushing from the advance due to the fact I could only get 10 deg. of advance from the mechanical curve. Now I get about 18 deg. of advance. I'm using the medium springs from the recurve kit that I bought. I don't have the vac. advance hooked up so I'm getting 31 deg total advance at around 3300 to 3500 rpm. I'm using autolite spark plugs which are 25's. I checked the stock plugs and they are supposed to be 26's. So I think the plugs I have are a little colder than what stock called for. I have 273 rear gears and the TH 350 trans. I have 10.1 to 1 static compression and I run Chevron 91 octain fule. I'm at close to 5000 ft elevation so I really shouldn't have a problem with pinging. The heads are stock specs. and the origional for the engine. I'm running the TA 212 cam with 4 deg of advance. My initial timing is set to 13 deg. right now. My Q-Jet has 74 primary jets and I'm using the richest secondary rods I have. I don't remember the numbers of the secondaries but they are only half the size of the stock cz rods at the tip. I also have a H hanger on the secondaries. My idle is set to 500 rpm in gear and 750 in park. I do get a bit of surging in the motor when I'm sitting at a light. That is to say I can feel the engine rev up and down maybe 50 to a 100 rpm while sitting at a light. I don't know what this is caused from or if this is normal. I have eliminated the pinging at lower rpm and don't really start to hear or feel it until I hit 4500 rpm. In second gear I don't get much past 3600 before the pinging really starts to get bad. I don't want to stay on the gas past that in fear of damaging the engine. I don't know if I'm getting enough fule to keep the engine from leaning out at the higher rpm's. I may not have enough fule pressure. What do you think now? Any help would be appreciated.
The 212 is going to surge at that rpm in gear...... mine was the same way. I tired of it and brought the idle up to about 700 in gear and 900-1000 in park. It wouldn't do that with the stock converter though as it would creep at the lights. It almost sounds as though the fuel pump isn't quite delivering enough volume at WOT or something. I had problems with an aftermarket machanical pump like that, so I boughta little better brand (AC) and have not have any delivery problems yet. A restricted tank pickup filter can cause that also by delivering marginal supply. Pinging is a tough one to call sometimes...... Mike
I agree with Mike, you may be leaning out at higher RPM. Are you running any type of fuel filter and where is it? As far as the plugs go, sometimes you actually need a hotter plug. My favorite plug is the Champion RV 17 YC(25). It's an extended nose plug(they have a wider heat range) and is the only one my engine likes. I tried AC and Autolite and they seem to foul on me. When they do, the engine starts to ping and run rough. You have a mild performance cam, so your idle won't be dead smooth. If it is objectionable, raise the idle speed. With 10.1:1 true compression and 2.73 gears, 91 octane is just not going to cut it. I would try mixing in some race gas. You may not need much to control the pinging, try mixing a gallon or two into a full tank. You shouldn't need to remove the advance bushing to get 18-20 degrees mechanical. I believe the stock Delco distributors allowed 18-20. You may be getting too much advance at high RPM, that is what the bushing is supposed to limit. Put a timing light on it and make sure that your not getting more advance after you think it's all in. Hope that helps.
