Timing set - Just making sure

[jpctln]

Well I adjusted the ignition timing this afternoon. I loosened the hold-down bolt before checking to see what the timing was set at previously, so I rotated the distributor before I realized what I was doing. Anyway, I put the timing at what I think is 14º BTC from the #1 spark wire, correct? The illustration shows what I put it at from memory, let me know if it's right. What is ATC and the 12 there for, btw?

Edit: This is on the skinny portion of the balancer, by the way, and withOUT the spout connector in.

 

[jpctln]

Also, if you can, explain to me what pinging sounds like and when I should expect it. I'm running 90oct gas right now and I don't hear anything unusual, but then again...I don't know what to expect. Let me know.

 

[jrichker]

ATC = After Top Center

According to your graphic, you are at !4 degrees BTC. That's pretty much optimum for a stock headed street car.

Pinging sounds like shaking a coffee can full of BB's. You'll hear it most frequently when you accelerate under load, like full throttle in 4th gear at a low speed/low RPM.

 

[HISSIN50]

neat graphic. wish i could do that stuff.

JR is right on, as usual (he meant 14, not !4). if you hear pinging, back it off a degree or two (or use higher octane gas).

if interested, i bet JR will post his cool list of causes of pinging. nice list.