Ping

[edison1970]

My motor has developed a ping. It's mostly at hard acceleration.  I thought it was maybe from a poor batch of gas but it has been a few tanks since I noticed it and it's still there. I turned the timing back but it still there. I pulled the Summit brand distributor and took it apart to put a FBO limiter in and possibly change a spring. The heavier looking spring didn't fit snugly on the post. The end of the spring that attaches to the post is oblong so the weight actually swings out before it starts to engage the spring. Is that normal? 

[Cuda Cody]

What compression ratio is the motor?

[Cudajason]

The factory heavy spring does have an oblong end that delays the action of the spring.

[Chryco Psycho]

Some of the factory springs were like that so yes it allows so rapid advance at lower rpm as only 1 of the 2 springs is tensioned .
Cooler air , carbon build up can add to detonation , Cooler plug could help but they can foul quicker .

[edison1970]

Compression is at 10.5. I was thinking along the same line about Carbon build up. I'm going to shoot some engine tuner down the carb and see if that helps. If you think that spring is ok, I'm going to leave it.

[Skid Row]

  Why not just use water? I have (Steam Cleaned) valves and pistons for years this way.

[70vert]

Interesting. Explain the process, just a squirt bottle of water into the carb?

Why not just use water? I have (Steam Cleaned) valves and pistons for years this way.

[BIGSHCLUNK]

I've done the "water" method a few times over the years. Warm up your motor, pour water right down the carb as you work the throttle. Usually gotta keep the R's up a little. Do it out side as black smoke will ensue. Its all the carbon blowing out.

[MoparLeo]

Another cleaning method is to dribble ATF down the carb. You must do this away from any streets or buildings as it will produce huge clouds of white smoke. Like a military smoke screen.
You said it developed a ping on hard acceleration.
Have you done anything recently that may have influenced it ? What is the rest of the story on your engine build and car.

[edison1970]

I've done the water method in the past in other motors. Very effective. I lean towards Engine Tuner  because I've used it on numerous small engines and outboard and it does a great job.
The motor is a 440 I put together 4-5 years ago. 30 over forged 6 pack pistons, Lunati 703, closed chamber heads. It runs strong. I'm on my 3rd carb. Holley Street Avenger 770, QFT 750 and now 800 cfm AVS2. Still have an issue with it idling a little rich. That's why I feel there is carbon buildup.  Been working on my step side project so the car gets put outside while I do body work so short run time just to go in and out.

[MoparLeo]

Do you go to the same gas station every time ? most people are creatures of habit and go to the same gas stations and the same stores to shop. Try going to a different brand of gas and see what happens.

[jimynick]

Some good suggestions. We used a blended method and used about 2/3 of a bottle of pop full of ATF. As both mentioned, bring the rpm up to about 3000 and feed the ATF to 'er. It'll smoke as described! Once it's in, shut the car off and let it soak for say, 5 minutes. With a 16oz. btl of water in hand, have someone fire it up, raise the revs again and gently feed the water to her. Don't get rammy with the water as you don't want to hydraulic a cylinder and rev it up and down for 30 seconds once all the water is in. You'll hear sounds and see ka-ka that you might'nt've have expected and hopefully you won't hear that ping anymore. We'd then take the car out for what we called an "Italian tune-up". Apologies to any Italians I may have offended. 

[Solarguy]

Check for vacuum leaks. 

[Skid Row]

  Great video today, Uncle Tony's Garage(You Tube) on what might help you out.

[edison1970]

Yeah. I was watching that. My question is, how do you use vacuum advance if you tie up both ports? Can't you just use the full vacuum port and attach it to the air cleaner?