how do i stop pinging?
 

i have noticed a high pitched clanking under my hood latley when i accelorate. i think it might be pinging. what does it sound like? i have about 9.0 compression and i use 87 octane. what are some things that might cause pinging? what are some steps to cure it?

Re: how do i stop pinging?
 

Sometimes it can be a timing issue, but can also be from low octane/bad gas. I have my timing dialed in, but if I run 87 my truck pings like crazy. It doesn't ping at all when I run 93. I'm sure there are other causes that I'm not aware of. Good luck getting the problem solved.

Re: how do i stop pinging?
 

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I agree with Dave and this is where I would look first. Check the obvious before you dive in deeper.

esll. :)

Re: how do i stop pinging?
 

If it goes away with better or higher octane gas then you have 2 options: Run the better gas, or retard the timing 2 degrees at a time until it goes away.

Before you go there though, make sure your vacuum advance is working properly. One of its main functions is to retard the timing during acceleration. It could be that your total and initial timing settings are fine and that it's just the vac advance that's not retarding like it should.

Re: how do i stop pinging?
 

Check your mechanical advance too, especially if the engine is hard to crank when starting. When waiting for my engine to be rebuilt, the dizzy decided to get stuck on full advance... :(

Re: how do i stop pinging?
 

Crm. 1972 cheyenne
chevrolet red and white
357ci, 9.0 comp, pro torker sr heads,
performer rpm q-jet, .454/.454 268H comp
Quadrajet carb, flowtech headers, 2.25 40 series
HEI, curve kit,TH 350, 3.07 gear

If this is the truck in question I see it has an HEI advance curve kit installed. I don't know how yours is set up but it may have too fast of an advance rate ( looser springs) for the compression and 87 octane gas. If using the lighter springs you can swap them for the next stiffer springs to delay the advance just a little bit. Or run higher octane gas or add a can of octane booster to each tank of gas.
Also what about coolant temps? If running a 195 stat back it down to 180 or so to also help the problem.
One other thing. An adjustable vacumn advance will help you to fine tune the curve too.

Re: how do i stop pinging?
 

:agree: with Boog, with the mild cam set up you have you might be advancing too fast. 9:1 comp is not that high on compression. Check your timing curve, something closer to stock might work better in your case.

Re: how do i stop pinging?
 

Did this noise just start without any changes made by you?

Re: how do i stop pinging?
 

Carbon build up can also cause this due to carbon holding the heat and acting like a glow plug.

Re: how do i stop pinging?
 

yes, the noise started with out me touching anything. i have a 180 thermostat.