Timing

[Doug&Deb]

My timing is set at TDC per the manual. I occasionally get some pinging on a hill usually when the engine temp is hot (not overheating). I tried setting it with a vacuum gauge but it really pinged. I run 87 octane with ethanol. I’ve rebuilt the carb and fuel pump with ethanol resistant parts. What adjustments need to be made for today’s gas? I’ve lowered the float level already. Thanks 

[Plymouthy Adams]

if this pinging is during light throttle or say slight incline in road....that is often attributed to too much vacuum advance....you can check your total advance with a timing tape or timing light with this feature built in.  Adjustment in this is adding/removing washers for to check the total movement of the points plate....

Edited October 14, 2021 by Plymouthy Adams

[Doug&Deb]

Thanks, I’ll check that. It’s a rebuilt vacuum advance. I didn’t think about that affecting the timing. As always your advice is appreciated.

[desoto1939]

Doug: I have also found that the manual is a good reference point. but as the engines get miles on them you always have to fine tune the engine. So TDC is a starting point but might have to retard the dizzy or advance the dizzy to get rid of the ping. Just some thought on the situation.  Not sure if this wil solve the issue but just wanted to add some input.

 

Rich Hartung

Desoto1939@aol.com

[Doug&Deb]

Thanks Rich.

[Sniper]

Compression ratio is so low and the octane available is much higher than when they were new that I am surprised it is pinging.

 

What plugs are you running?  How do they look?  Might be too hot a range and/or has an oil burning issue.

 

What temp thermostat are you running and how hot is your engine?

 

I ask because since it seems to ping under a load with the engine hot I am wondering if maybe your cooling system is marginal.  When I cleaned out my radiator fins I was surprised at the amount of dirt that old honeycomb core held.   

[Doug&Deb]

Can’t remember what plugs I’m running. I’m at work. Thermostat is 180. This only occurs at the same spot on my drive home from work. I’m pulling 3 different hills in succession. Engine temperature is 200 by the last hill and that’s when it pings. Engine was rebuilt about 8000 miles ago and the radiator is aluminum.

[greg g]

I bit of a carbon deposit that starts to glow from heat maybe the culprit in pre ignition.  Have you tried to retard it by a couple degrees?  How do your plugs look?

 

We were out yesterday doing a lot of hills and even pulling some long grades in overdrive.  No discernable pinging on generic 87 with ethanol.  My timing list says my at idle timing is a 5 degrees before TDC.  Starts well runs good, gives me 17 to 19 mpg.