Just my 2 cents. It is not the carb it is the ignition, brand new or not.

 

To address the oil problem...have someone follow you on the Interstate, accelerate at WOT from 40-80 then back all the way out of the gas. Smoke on acceleration is rings....deceleration is valve guides.

 

KBunny, you stated the distributor was new. It is very easy to get a new dizzy off a tooth when you reinstall, and thus making your timing marks off. You stated that you were going to make a few timing changes, but you did not think the problem would go away. I am curious to see if backing off your timing solved the problem. If no matter what you do with the timing does not change the pinging, then you definitely have some sort of pre-ignition due to extremely lean (hot) carb settings, carbon deposists, or something similar. If that is the case, have you also double and triple checked to make sure your plugs are the proper heat range????

I have the same intake setup as you. My factory calibrated Edelbrock 600cfm was setup a bit lean, as I had the lean surge at certain RPM's. I read over the owners guide (available online if you do not have a copy), and went by the suggestions for a richer metering rod. Problem solved in my case.

Good luck, Aux

 

The only thing that could be giving trouble when setting the timing is a slip of the damper pulley. The timing marks may be off. The orientation of your distributor will changes where #1 is in relation to the rest of the engine, but, after properly timed, has no affect on the timing marks themselves.

BTW, leaving the vacuum line hooked up to the proper port on your carb will not affect timing at idle. If it does, you're either at the wrong port or your carb is f$#%&d up. The dizzy port on your carb won't become affective until after the throttle blades are opened. You can see these ports in the primary throttle bore if you look at the bottom of the carb.

 

I (we) just tuned the 650 version of your carb yesterday. Had it on the dyno to boot (that was fun). I read the edelbrock carb owners manual several times and didn't feel like I was capable of tuning this, but once I got in there and started looking at how the thing works, and watching what changed when I swapped metering rods, springs and jets, It started making sense. I'm in good shape now. I'd recommend taking notes every time you change something so you can compare the results to previous combinations. An oxygen sensor is awfully helpful too. Went back last night and read that same manual after having my hands on, and it all made good sense. I'm sure you have more experience than I.

Isn't it true that a lean mixture can result in pinging? If in his case, it happens before the secondaries open, doesn't that mean the primaries could simply need to delivera richerfuel mixture? Would that (lean primaries) not produce his exactsymptoms?

 

Pinging is caused by incorrect timing. Pinging is caused by incorrect timing. Pinging is caused by incorrect timing. Pinging is cau...............

 

im confused[&:]

 

Colorado Mustang, I meant that if the motor was rotated while the dizzy was being replaced and/or you are off a tooth while replacing the dizzy, unless you are 100% sure your #1 piston is at TDC while your rotor is pointing to #1, your initial setup will be off whatever degree your rotor is. You can compensate for this via turning the dizzy housing, or removing the dizzy once more and relocating it properly.

So if you are banging your head because you did not quite grasp what I was trying to say, sorry for the confusion.

If you were attempting to bang my head, might I suggest you take a flying leap at a rolling donut.

Good day.


And Soaring, while timing is usually the culprit for pinging, an extremely lean fuel mixture WILL cause high combustion temps, which can also lead to pre-ignition/pinging.

Aux

 

Looks like everyone is getting twisted up over this one.
Point 1: If your timing light is telling you that you are @ 6 BTDC then that is were you are at. I don't give a hooty crap what tooth you are on.
Point 2: Could it be a lean condition that is causing the ping? Yes but I doubt it. It sounds to me like the dizzy has the wrong advance curve.
The engine is not running hot and it should be if there is a lean condition. Look at the plugs and see if it is running lean, if not it has to be the timing. Of course I'm just and old fart that don't know diddely squat so take it for what it is worth.

 

I'm an old fart too and don't know diddly squat either, so don't adjust the timing to get rid of the pinging on my advice.