My 400cid 351 Windsor stroker is only running 9.2:1CR but it's pinging like crazy on the 85 octane here in Colorado. I've checked the gaps on my plugs and the points, retarded my timing so far back it's probably -4 initial (timing light doesn't go below 0). It STILL pings!!!! WTF!!!
I topped off with half a tank of premium and added a double dose of 108 octane boost. Pinging and dieseling gone, but NO BALLS. What the hell is going on?
"Blue Mesteno" wrote in news: snipped-for-privacy@comcast.com:
They probably just replaced MTBE with ethanol there?
Sounds either lean or hot, does not sound like too much timing. Start by setting your timing back to where it should be. I live in the Springs, and I have
10.5:1, Mallory electronic ignition with 10* initial and 24* mechanical, and EFI. I generally run mid grade. Unless it gets really hot, I don't have pre-ignition problems.Check for the simple things first: loose vacume hose, cracked vacume advance can, blown intake manifold gasket, air in the cooling system, etc.
What changed recently?
I had a pinging problem on my 289 and tried all the typical tricks, just like you, to no avail.
Called a garage to have a "pro" check it out, and they suggested I try combustion cleaner first.
Shot a $6 (Canadian) can of it into the carb following the instructions (fast idle, let it sit after, etc.) and the pinging all went away. Now I can even use the lowest octane pump gas, no problem.
Worth trying first. Supposedly the pinging was caused by carbon build-up, heating up red hot and doing the pre-ignition thing.
Michel.
".boB" wrote
Nothing. It's just gotten gradually worse and worse. The engine is brand new. Less than 5000 miles on it.
Unless it's really out of tune, carbon in the combustion chamber are not very likely. Check for vacume leaks and lean mixture. Be sure and check the timing. If the hold down bolt wasn't secured, the timing will gradually creep.
".boB" wrote
If only it was as easy as any of those things. The only thing can think of right this instant is that the brand new balancer was fugged.
Sorry, you lost me on that one. How would a bad balancer cause pinging?
".boB" wrote
If the rubber slipped and the timing was read incorrectly. Why would it start out at 12 degrees and end up at -4 if something REALLY strange hadn't happened.
OK, I get it. Good point. If you reset your timing based on a slipped balancer, it would be pretty far off. Fortunatly, that's pretty easy to check. Stick your thumb in the number one spark plug hole, and turn the crank with a wrench. You can feel when it's pretty close to TDC, and the timing marks should match up.
Have something to add? Share your thoughts — no account required.
Ask the community — no account required