The motor setup is listed in my signiture. The ignition is a MSD6AL. HEI distributor, with the msd converion, so it uses a normal coil, stock HEI wires, plugs are ACdelco R45's. I got the plugs for a 76 buick, so they came gapped at .060. New cap/rotor. Timing is around 10-12 at idle, and total is about 30-35. Stock wieghts in the distib, with medium springs. I don't have a tach to hook up in the engine bay, so I'm not sure where the timing is coming in at exactly. Engine runs at between 180-195 deg. I get some pinging when I get on the gas. I'm running 93 octane. It really shouldn't have any pinging problems setup like this. I can't find anything wrong. Anyone have any suggestions, or experiance with a similair setup?
You might try reducing the gap down to about .045 , I am running .035 on mine with no problems other than a bit of deposits from racing fuel once in a while. That and you might try taking the timing back 1* or 2* and see if that helps. There are a few other things that can contribute to spark knock...... carbon build up is one. How many miles on the engine? Mike
HEI's have alot of mechanical timing in them. Are you sure you know what the total is? You say 30-35*. It sounds like you really aren't sure. You have to be. It gives you a baseline with which to change things. Are you running vacuum advance?
Hi, I started getting some ping since they stopped selling the 100 octane I used to mix with 94. They now sell 93 and have discontinued the Ultra 94. I have done some research and so far changed my thermostat to 160* and flush the cooling system(added red line water wetter). Car now runs 40* cooler and has reduced the ping. I hear it going about 70 and when I floor it. Some other tips I have read: back off the timing, richen the fuel mixture, use a colder plug range, higher octane, clean out carbon build up. I have 10:25-1 compression as well, and high compression engines are prone to pinging and knocking. Check out: www.buickperformance.com under combustion abnormalities and this may help. Good luck! Mark
67Coupe, Thanks for your info. I've been dealing with this problem for over 20 years. Had not considered lowering the cooling temp. A few years back, I asked a group of top BCA tech gurus about this 340-4 pinging issue. After a few moments, the senior guy, a former Buick engineer said: "Turn up the radio".
Harry, Since I changed the thermostat , the pinging has greatly been reduced and everything under the hood is so much cooler after a long ride. I will probably change back to 180* in the Fall. I am also using more water and less coolant to help. The car ran great on Sunoco Ultra 94 octane but they stopped selling it here last year. That is the first time I could hear ping under heavy load when I used 93. The octane boosters in the stores only raise it .2 octane. I have read many of your post and you are very knowledgable! When I was a kid, turning up the radio and having seat belts that could open a beer bottle seemed to cure alot of my cars problems! Mark
