Pinging problem

[gwstang]

I have had a little pinging problem with the '66 5.0 HO every since it was rebuilt. I was using the middle grade gas to stop this. I started putting the non-ethanol fuel in when everyone started having problems with that 10% ethanol mess screwing up carbs, gaskets etc. The problem is that the non-ethanol is like the lower grade fuel, can't get it in a higher octane. I am wondering if anyone else runs into this...or do you all use jet fuel or something...lol :roll I run the timing at 10 deg btdc (had it at 12 but thought to try this first, still doing it) I know the AOD tranny has a little to do with this, because if I am going along behind someone that goes slow up a hill and gets slower I have to manually shift down a gear or it will ping like crazy. I still have the 3.5 gears in the rear. It downshifts fine but I don't like having to kick it down like I am passing just to stop the pinging. It would skip 3'd and go straight to 2nd if I do that (which is what it is supposed to do). I guess I will have to get some fuel additive at the parts store to add to the gas? Thanks, Gary.

 

[Midlife]

Pinging can be due to lower grade gas or too much advanced timing. Since your timing is a combination of base (initial), centripetal (mechanical weights in dizzy) and vacuum advance, you can really only reduce your base advance or change your weights. I'd drop your initial advance down another 2* and try again.

Adding additives to the gas to increase octane is futile; it only adds about 0.2 octane.

Check around for marine gas stations; they often have premium (91 octane) in pure gas.

 

[apollard]

It's lugging at light cruise / part throttle when pulling tall gears, right? If so, that is the vac advance setting. A test would be to remove the vac line and plug it. If it stops pinging, you need less vac advance. Many vac canisters are adjustable by an allen wrench in the port where the hose attaches. Try adjusting for less advance.

 

[gwstang]

"Adding additives to the gas to increase octane is futile; it only adds about 0.2 octane."

Did not know this! I could pi** in the tank and probably add that much...lol

"Check around for marine gas stations; they often have premium (91 octane) in pure gas."

There is a place just down the road from me that sells non-ethanol for the boats going in the lake and iirc there are 2 grades at the pumps, hi and lower. The higher will work great I bet. He does charge more for this "privileged gas" that doesn't have our food in it (corn) About .15 more a gallon :wtf I will give it a try. Thanks

 

[gwstang]

It's lugging at light cruise / part throttle when pulling tall gears, right? If so, that is the vac advance setting. A test would be to remove the vac line and plug it. If it stops pinging, you need less vac advance. Many vac canisters are adjustable by an allen wrench in the port where the hose attaches. Try adjusting for less advance."

Dang, I never thought (or heard) of the vac line trick. I have a rebuilt Ford distributor. Would I turn (using allen wrench) it outward to reduce timing? I have a feeling it is going to take a combination of what Randy said, plus what you have mentioned to straighten this out. Thanks, Gary.

 

[apollard]

I don't recall exactly, I've always just hooked it up to manifold vac at idle and then adjusted it using a timing light. That way you can see where you start, and where you end up. I THINK it turns clockwise to decrease (ie, screw turns in to limit travel).

 

[gwstang]

I'll give that a try this weekend with the timing lite, good tip btw!

 

[gwstang]

i did try some mid grade non-ethanol and it worked to stop the pinging. I am going to do some adjusting and see if the regular grade will work afterwards.