Chrysler 440 ignition timing.

Anyone know what the correct timing figures are for a 1973 440 motor?

(as fitted to a Jensen Interceptor, if that makes any difference)

Ta

--
Pete M

Mercedes 260E, Porsche 911 Carrera 3.2
Ford Capri (ressurection started)
"Never moon a werewolf"

COSOC #5
Scouse Git extraordinaire. Liverpool, Great Britain

 

In '72 it was 10° BTDC, vacuum advance hose disconnected from distributor
and plugged. '73 probably not too much different.

 

10 degrees before DTC with the automatic (All interceptors were
automatics IIRC) and I think the standards were the same.
In 74 the standard 4bbl went to 5 degrees, and the Magnum to 2.5

 

Anyone know what the correct timing figures are for a 1973 440

The book may say 10 BTDC, but is that what he wants if he's going to
be using the relatively low octane gas available today? He may have
to back it off to zero BTDC if he wants it to run cool (and not ping).

What if he wants (or has to) pass an emissions test? On pump gas?

I've always set my timing at what-ever setting gave the best vacuum at
idle.

Is this mechanical points/condensor, or electronic ignition?

 

The book may say 10 BTDC, but is that what he wants if he's going to

As others have already said 10 is the correct number. Compression was
dropped enough by '73 that it will run fine on regular unleaded or mid
grade at worst. My '73 Imperial ran on regular unleaded even in the
FL heat without ever pinging.

Steve B.

 

There were a number of different distributors used over the years, and I
don't know exactly which one you have. In any case the TOTAL timing (all
mechanical advance IN, no vacuum advance) on a Mopar big-block should be
around 35-38 degrees. Usually that means a "base" timing of 10-12
degrees BTDC at idle with the vacuum advance plugged, but some of the
late "smogger" distributors had a ridiculously long advance curve that
required you to set the base timing at 0 degrees. (Yuck!).

Basically, if you can't find the exact spec, either set it by total
timing and let idle fall where it may, OR try it at 10-12 BTDC and back
off if you get pinging under WOT acceleration.

Fuels have changed so much over the years (and the odds are so good that
the distributor or other engine components have changed) that tuning to
where it runs best is often the best way to go anyhow.

 

In

Electronic ignition, standard set up I think...

Thanks to everyone for the info, I'll have a look at it at the weekend..


--
Pete M

Mercedes 260E, Porsche 911 Carrera 3.2
Ford Capri (ressurection started)
"Never moon a werewolf"

COSOC #5
Scouse Git extraordinaire. Liverpool, Great Britain