65 T-Bird Pinging

[R J]

Hello, The 65 t bird I just bought keeps pinging under a light to moderate load. I use premium fuel, Timed @ 6 tdc, Carb adjusted, new timing chain / gear set. I am stumped ? Tried 4 tdc and still pings with car gutless and running poorly. Stock 390 with points. Anybody have an idea what the heck could be the problem?? Thanks, Rj

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[Grahamp]

Carbon deposits on the cylinder heads can increase the compression ratio or cause pre-ignition by acting as a glow plug.

 

[jack-in-sac]

How many miles on the engine? Even if it still has decent compression there can be problems. Have you tried timing it by vacuum?
good luck, J.

 

[R J]

Carbon deposits on the cylinder heads can increase the compression ratio or cause pre-ignition by acting as a glow plug.

I scoped the cylinders with a camera.. All clean. Thanks anyway

 

[R J]

How many miles on the engine? Even if it still has decent compression there can be problems. Have you tried timing it by vacuum?
good luck, J.

95 k miles on car. Timing and total advance is accurate. I just found the car. Stored 10 years. Along with fluids and soft parts I replaced the cold autolite 44 plugs with the hotter proper autolite 45 plugs. Maybe that's it? I'll put 44's or 43's back in and keep my fingers crossed. Thanks for your input.R J

 

[64ZCODE]

I wonder if your vacuum advance is working properly? To check, have your timing light hooked up at idle then watch as you goose the engine rpm, you should see timing advance to somewhere around 30 degrees BTDC. If it doesn't, then there is a problem with the vacuum advance, centrifugal advance, or vacuum is not getting to the advance.

By the way, on timing, the 390 seems to run best with initial timing of 15 degrees BTDC. That's where mine is set and there is no engine pinging. I know spec is something like 6 degrees BTDC, but that's not the real world.

Good luck!

 

[R J]

I wonder if your vacuum advance is working properly? To check, have your timing light hooked up at idle then watch as you goose the engine rpm, you should see timing advance to somewhere around 30 degrees BTDC. If it doesn't, then there is a problem with the vacuum advance, centrifugal advance, or vacuum is not getting to the advance.

By the way, on timing, the 390 seems to run best with initial timing of 15 degrees BTDC. That's where mine is set and there is no engine pinging. I know spec is something like 6 degrees BTDC, but that's not the real world.

Good luck!

 

[R J]

15 BTDC ..WOW! I'll try checking advance as you said and go from there. One way or another I have to stop the pinging. Thanks for your help.

 

[64ZCODE]

Hey RJ, one other possibility: if your timing light has a "direct advance" adjustment knob, make sure it's set at "0" before you set the timing. I found this out the hard way when I was having a pinging problem with one of my cars similar to what you're describing.

Doug

 

[kees]

15 BTDC ..WOW! I'll try checking advance as you said and go from there. One way or another I have to stop the pinging. Thanks for your help.

Did you check for a vacuum leak. That could cause a lean condition that may cause pinging. Hope you get this worked out.