How much is too much timing?

[Ronbo]

I can get 14 out of it before it starts pinging but that seems like alot. I have it dialed back to 10 right now but it sure ran a whole lot better up at 14. Compromise with 12? I dont want to burn up the engine.



Ron

 

[rbohm]

8) if you can run 14 initial timing before you get detonation, go for it. to a point the more timing you can run the better.

 

[MustangSix]

The chambers in this engine are "lazy". They need a lot of advance just to get all the fuel burned and tend to run better with more advance dialed in. But it takes some other adjustments to the curve to make it work out.

At some point, however, too much advance causes the cylinder to fire too soon and can cost you power because the charge is pushing back on the piston as it moves towards TDC.

With 14 degrees initial, you may be a couple of degrees over the line at higher speeds, so you'll have to cut back the mechanical or vacuum advance a couple of degrees to maintain the same total advance number.

 

[fordconvert]

I have found that restricting the amount of movement in the vacuum usually does the trick.

 

[CZLN6]

Howdy Ron and all:

What are the conditions when it you start to hear ping? What do your spark plugs look like? What heat range? What octane gas? Is it stock CR? What Carb?

You are most likely to hear ping while cruising at steady highway speeds with slight acceleration. At highway cruising speeds your distributor has reached maximum centrifugal advance, and is drawing maximum vacuum advance too. If you nudge the accelerator the vacuum advance is supposed to quickly retard, reducing the likelyhood of ping. If the vacuum advance mechanism is dirty, sticky or lazy in anyway and hangs on you will get ping.

Headers will tend to lean out the air/fuel ratio. Usually stock is too rich so this is usually not a problem. Have you checks your timing mark for accuracy? Are you using a ported vacuum source for vacuum advance?

I'd run 12 degrees of advance while I checked out the other details.

 

[Ronbo]

I'm running a DGES 38mm with a header and no other changes, fresh engine and I'm still working out the bugs. :roll: I have the mechanical advance in the 13 slot (does that mean 26 degrees total?) and a new vacuum advance, the distributor is new also....shoot the whole engine is new if I think about it long enough! I do have a bit of surging at low cruising speeds so I better check jetting before going any further. I'm leaving it at 10 for now to be safe.

 

[BIGREDRASA]

I can get 14 out of it before it starts pinging but that seems like alot. I have it dialed back to 10 right now but it sure ran a whole lot better up at 14. Compromise with 12? I dont want to burn up the engine.
Ron

My biggest fear is the pinging I don't hear, under partial load at highway speed. One thing I do is put the car in 2nd for an AT, and floor it going uphill at around 10-15 MPH. You can also do something similar with a manual by lightly lugging the engine and listening to how badly it pings.

 

[66 Fastback]

I have the mechanical advance in the 13 slot (does that mean 26 degrees total?)

You are correct 13 equals 26 degrees on the crankshaft. If you are getting 26 deg centrifugal plus your 10 deg mechanical, you might be in the ballpark on what you want for total advance at WOT.
Now it just may take some playing with the springs to change when it comes in if you are still getting pinging or if you want a more agressive intial setting.

Doug