lately i noticed my pistons are making a ringing noise, but they are only doing it on the right engine bank. the engine was rebuilt 6 months ago. block bored .030 over, new crank, pistons, rings, gaskets. i used my edelbrock cam (.484 lift), intake (performer 390) and used edelbrock 750 carb (just rebuilt 1month ago).

when i step on the gas the pistons start ringing, or if i was going up a hill or passing someone they make a ringing noise. im just worried i might ruin this engine.

any thoughts/commits greatly appreciated. my new neighbor adjusted the carb just before the bbq at mikes', running better he said the engine was running too rough.

plus i dont know how to adjust carbs.

 

Sounds like engine pinging. Timing? Gas Octane. What's your compression ratio? If it's under 10:1 you should be able to get by with good quality gas. If your using watered down gas .... Ooops ... Check you timing and total advance. Perhaps you have too much total advance. Many things are possible in this area and you don't want to just cover up the problem by using 100 Octane if you don't need to .... However, you can use some 100 Octane in there to see if the pinging goes away. That would most like indicate a timing issue if your under 10:1 compression ratio. In my Firebird, which is perfectly timed. It will click once or twice on low end torque take offs with A/C on. With the A/C off it doesn't click it just goes. On that car, I test by getting it rolling put into second and stepping on the gas pretty good in second without spinning the tires. That seems to put the most load on it for pinging testing.

Good Luck .... I'd start with all three of the following:

1) make sure your not over 10:1
2) Make sure you have high quality premium gas(if it needs it - my 8:1 FE runs on the cheapest regular gas)
3) Check the timing. initial and total advance

Carbs could be an issue .... But, normally it doesn't produce a pinging/ringing sound.

There is always a possibility of U-joints unless you have heard this noise just sitting in your driveway. That would rule out U-joints. They will ring if they are going bad during acceleration sometimes.

How this helps

 

I have a timing light, we can make sure the advance isnt going too far.

 

my timing is dead on, it only does this when im going down the road. in park and revving the hell out of it, no ringing. and i been using regular gas, no additives. the compression is about 9.3:1 or maybe 9.4:1.that was told to me but engine-re-new here in modesto. they shaved the block some, to make sure is was straight and level. the guy who did my heads, he shaved them too, again tomake it straight and level.

 

I also say it is pinging from pre-ignition. If your plugs get too hot then they will ignite the gas too soon even before the spark is sent from the distributer. Check the plugs for color. The insulator cone should be tan or grey. I bet yours are white. This can be caused from timing, or too hot of a plug, or too lean of a mix on your carb. If you want an easy test after checking the plugs, then as previously stated, buy a tank of gas with a higher octane rating. The higher the rating, the cooler the burn. Good luck, Jag

 

jag, and all who responded;

thanks for the input all. ill check the plugs tomorrow,( 9/16/07). but i have a full tank of regular unleaded gas. been thinking about putting some 100 octane when the tank gets low enough. only get to use the truck on most weekends.

 

well i changed the plugs, they were tan/grey in color. the plugs on p/s had some carbon build up on the plug threads only, not on the tips. i also checked the timing, ex-neighbor had it set at 12B, the book i have said it should be 6B. thats where i set it now. took it for a test run, good. still has a small amout of ringing/pinging really have to listen to it. but it only starts making the sound after i run about 10-12 miles on it. the engine needs to be warmed up pretty good for the ringing/pinging to start. i still have a 1/2 tank of regular gas in it. im waiting until im low enough to fill it with 93 or 100 gas, plus i need to replace the gas line at the tank, it is showing its age of cracking, but being unmarried to a blonde i keep forgetting. i guess the blondness does wear off. lol

 

Maybe it starts off at 12*, but might go to 45* or so total timing. That's the timing I was referring to; total, not initial. Just a thought. The high octane wont ping hardly at all with high timing.

 

ok thats where i get lost, im not sure what the total timing is. would my vacuum advance have any thing to do with it???? just wondering. i also have a petronix upgrade in the dist. also. neighbor was also suggesting i change my needle or something to that effect in the edelbrock 750 carb, if so i dont know what to get. not that great when it come to the carb.

 

The vac advance mainly does its thing under heavy load & part throttle action. Total timing is just that, the absolute maximum it'll get. To replace a needle(metering rod) in an Edel carb, it just takes a 1/4 nut driver or a T-15 torx bit. That will allow for making it leaner or richer, depending on which is purchased. There's a nice flow chart on the edelbrock site to know which rods or jets to buy.

 

Total timing is just that - the total amount of advance you set. There are just two things that set the total - one being where you set the distributor - normally 6 to 12 degrees advanced. This is sometimes called the initial timing.

The second is the amount the plate that holds your points (or petronix module) advances when you speed up your engine. There are two flyweights on this plate that cause it to move in the advance direction according to your RPM.

You can change these if needed, and you should check that the plate is rust free and moves easily. If you watch your timing marks when you set your initial timing (should be 8 to 12 degrees) and increase the engine RPM, the timing should advance. Total timing should be somewhere around 25 to 30 degrees, and should all be in when the engine is turning about 3 k RPM. Increasing the RPM over 3 k should not give you any more advance.

The vacuum advance is misnamed - it should be called the vacuum retarder. What it does is to retard your timing when the engine is under a load (low vacuum). It connects to the same plate that we discussed above, and moves it in the retard direction (opposite the direction the fly weights move it).

Just suck on the end of the vacuum hose connected to it, and you should see the plate move. On most, but not all, distributors you can adjust this. There is an adjustment screw located inside the vacuum hose bib. Just turn that screw.

It is a lot simpler than it sounds - and I am not explaining it well. If I have managed to confuse you just email me and I will try again.

One point people often miss is that we are not just adjusting a mechanical process. We measure everything from Top Dead Center of the piston travel, but that is not where we want the spark to occur.

We are attempting to fire the spark plug at the time that will produce the most power from the exploding fuel charge. This is a dynamic process - the fuel starts to burn, reaches the point of maximum pressure, and then dies off.

We want this point of maximum pressure to occur when the piston is moving down its power stroke. However, as it takes some time for the fuel charge to burn and produce maximum pressure, we start the process early, before the piston even reaches TDC. But we can't start to burn too soon, or it will create pressure against the piston as it moves up toward TDC.

Nor do we want to start the burn too late, or the point of maximum pressure will occur after the piston has moved too far down its power stroke, wasting most of its power.

Obviously, the time it takes for the fuel charge to burn is the main factor - and this changes. Summer blend gas takes a different time than winter blend, different brands have somewhat different characteristics, the temperature of the air - it all changes. This is why you have to adjust your timing for different seasons, and occasionally for different brands.

 

ty willeyb and neverenufhp.

 

On mine, when the vac cannister gets vacuum, I get a few degrees of advance. I havent seen too many that retard timing. If it was I sure wouldnt hook it up.

 

OK, the effect is the same - change the timing acording to engine load. I think of it as a retard device, but the industry thinks of it as an advance device. Which came first, the chicken or the egg?

And yes, most race setups do not use these - they are always at WOT.

Vacuum advance works by using a vacuum source to advance the timing at low to mid engine load conditions by rotating the position sensor (contact points, hall effect or optical sensor, reluctor stator, etc) mounting plate in the distributor with respect to the distributor shaft. Vacuum advance is diminished at wide open throttle (WOT), causing the timing advance to return to the base advance in addition to the mechanical advance.
http://en.wikipedia.org/wiki/Ignition_timing

A heavily loaded engine, however, will likely detonate with the high levels of spark lead a lightly loaded engine can tolerate, so a load-sensing unit that uses engine vacuum to advance spark in light-load conditions is added to the distributor. As engine load increases and vacuum levels diminish, vacuum advance reduces spark lead to lessen the risk of engine-damaging detonation.
http://www.highperformancepontiac.com/tech/vacuum_advance_tech/index.html

 

Ok, I gotcha, that's what I thought you meant.