[Kikin302]

I'm thinking on bumping the timing on my 87 GT a couple degrees. But, I have heard that if you bump the timing too high the engine starts to ping. My question is, what is pinging???? Thanx in advance for your help guys.

[302THEBOSS]

Pinging is also known as detonation. It is when the fuel begins to ignite before it is supposed to, and it doesnt ignite as it does whent he spark plug sparks. It will ignite in uneven spots in the combustion chamber, and depending on when it occurs and how bad it is, can be extremely harmful. It can dent the top of your pistons, and causes more heat. Its robs power too. You dont want it. I think you should be able to bump it up a bit though.

[meangreen92]

If your exhaust is too loud, you might not be able to hear it. But if it's happening, it should occur above 3500 RPM, if you floor it while driving.
It'll come from the front of the car, and sound a little like a ball bearing inside of a beer can - for lack of a better analogy...

[Bonham]

I have a 1995 gt stang and its also pinging, it started doing it after i put a tuneup on it. i replaced the sparkplugs with irridium plugs and oem dist wires. since then I had to replace the distributor core and the harmonic balancer and set my timing many times and its still pinging.
What should I do?

[crazycarnut]

Originally Posted by Bonham

I have a 1995 gt stang and its also pinging, it started doing it after i put a tuneup on it. i replaced the sparkplugs with irridium plugs and oem dist wires. since then I had to replace the distributor core and the harmonic balancer and set my timing many times and its still pinging.
What should I do?

could be your plugs are to hot.

[cnumartyr]

Pinging is caused by heat build-up in the cylinder pre-igniting the air/fuel mixture or timing.

Lean Air/Fuel Ratio
Too Much Timing/Low Octane Gas
Too Hot Plugs

All of these can cause pinging.

As for the tune-up guy, check the part number on the plugs. If they are motorcraft they should be something like ASF-32R. The 32 is the heat range and 32 is stock for a GT. 22 Range for Power Adders.

Lean Air/Fuel can be checked on a dyno or using a wideband O2 meter. Idle should be around 14.7:1 while WOT should run down 12:1 (or around there).

I would go into an explanation of Octane and Timing and what is actually happening but there is a section for it on the tech page. Basically if the flame front hits the piston before it's reached TDC it'll cause pinging and pitting of the piston.