While timing my '64 200, inline six for the last year or so. I've found that when I set the timing at 12 degrees BTDC like the manual says. I have a dieseling efect on the engine. It clangs out loud, if thats called dieseling. But, over a period of time I'ved moved the the timing to just about 3 degrees on the engine block scale. I get better performance it seems, but it does start dieseling when I pass at 60 MPH. Is this whole philosophy correct or am I damaging my engine? Any help would be appreciated...ZZ
Howdy ZZ Top:

Dieseling is usually the term used to describe an engine that runs on after the ignition key has been switched off. It's usually caused by an overly rich or high idle.

I don't think that's what you're describing. I'd recommend that you start solving your problem by making certain That your timing mark is accurate and is actually indicating top dead center. If you're describing ping, knock or pre-ignition there's a strong possibility that your timing ring on the damper has slipped or moved and giving a false reading to the timing light. This is not unusual.

Pre-ignition, knock or ping is definitely harmful to your engine and you should find out what's causing it and get it fixed.

What do your plugs look like?

Check it out.

Adios, David
I've been tracking my plugs every oil change and their're looking better every time. No oil residue, just that light gray color. If I repair this, with a good mechanic. Would it be expensive?
If there is no problem with the timing marks.
And there is no damage from the advanced igniton you may have had for a year or more.

Then it's a simple tune-up.

If you are off on the timing and have been for a year? And your car is pinging to the point of engine trouble, you could be in for more expensive work.

Figure something reasonable for a tune-up under $70, and I got a chain installed for $200.00 when mine was bad.
Talking to my foreman about my engine, he suggested a few things. Check my vacuum advance, by disconnecting the hose to my distributor diaphram and sucking on it to see movement. Remove my #1 plug and rotate the engine until the 1 piston is TDC, check the position of my rotor to see if is on the Zero mark. The distributor may be one notch off. All in all if my engine setting is not operating correctly at 12 degrees BTDC, something is wrong. I'll take it one step at a time...ZZ