68 Dodge Charger 440 Running HOT - Follow Up

[Charger68RT]

I want to thank the group for advice in helping me resolve my running HOT 440 RT Charger.  Per your direction I installed a mechanical temp gauge and emptied the fuel tank and starting running VC12 racing fuel.  The motor no longer runs Hot and stays at around 185 - 190 degrees.  I just need to wait for the warm days of summer to see how it will run when warm outside.  Huge improvement from before.  Next question and issue is my timing.  I set the initial timing at 10 degrees BTDC at 650 RPM with the vacuum advance removed and plug.  Once completed I normal up the vacuum advance and start getting the following readings at the listed RPMs:

2000 RPM - 40 degrees BTDC
3000 RPM - 47 degrees BTDC

revving the car higher and the timing never goes beyond 47 degrees BTDC

These numbers seem way off as the Dodge Service Manual states the following:     

710   RPM - 10.3 to 12.3 degrees BTDC
2300 RPM - 14 to 16 degrees BTDC

The numbers I'm getting are well over double of what they should be.  Could this have led to the heating problem I had with running todays hi test at 93 octane?
I tried playing with the timing but had no real luck in lowering these degree numbers.  How do I correct this?  Change springs and weights in the distributor?  The car runs WILD with the racing fuel!  But at $80 a can for 5 gallons does not last long.  Appreciate the feedback and direction.         

[DAmatt]

Hope this is of help to you, I think you are measuring with the vacuum advance engaged, and the manual takes it with vacuum disengaged and plugged. 47 degrees BTDC is OK with vacuum coupled. If you take the small hose out of the vacuum canister on the distributor, and plug it with a bolt/screw, then you should see 32-38 degrees BTDC. Most agree that 34-36 is a good place to start.

I don't know what to say about the 14-16 degrees BTDC @ 2300rpm... That's a good idle advance, centrifugal advance should engage at that rpm, it should take it to high 20s at that rpm?

Also, make sure you have a GOOD timing light, and also check whether it has an advance knob, if it is not set at zero, it will give a false reading (that's a rookie mistake I once made).

If you disconnect and plug the vacuum hose on the distributor, have ~14 initial (idle) advance, and ~35 total (at say 3000rpm), timing is okay.


Next would be fuel - does the engine ping on pump gas? Maybe it's too lean, so it burns hotter, thus the overheating, thus why racing gas helps. Maybe play with the jets for a richer mixture, and see if that remedies the problem.


Finally, what are the specifications of your engine? What pistons, cam, compression ratio/piston height, head milling, head gasket thickness? If you have a 14:1 monster, that would explain things