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318/340 igniton timing

Mopar Muscle
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318/340 igniton timing

gypsyjet gypsyjet
New User | Posts: 2 | Joined: 12/12
Posted: 12/06/12
11:21 AM

Hi everyone,

I Just bought a '72 demon and was wondering how many degrees advanced I should set the timing. I cant see the block casting but it is either a 318, 340, or 360. Ive been working with old fords my whole life and just got into mopar.

waynep71222 waynep71222
User | Posts: 246 | Joined: 04/12
Posted: 12/06/12
03:10 PM

318 2 bbl in the 73 model years are set at TDC..

there are several variations on 340 and 360 depending on the distributer numbers
i sure hope there is a tag on the distributer still..

there are several variations if you have a 340...
california emissions or federal emissions standards
manual transmission or automatic..
340 cal  automatic  see foot note 3..
340 fed automatic  2 1/2 BTDC @ 750
340 cal/fed manual 5 btdc @ 750

360 see foot note 4...

foot note 3...
early production 2 1/2 @ 750
late production TDC @ 750

foot note 4..  
models with distributer # 3656780  is TDC at 750 RPM
models with distributer number 3755336 is 7 1/2 BTDC @750 RPM
models with distributer number 3755337 or 3755335 is 5 BTDC @750 RPM

timing is set with the engine at normal operating temps.. and the vacuum hose to the advance disconnected and plugged .  

gypsyjet gypsyjet
New User | Posts: 2 | Joined: 12/12
Posted: 12/06/12
08:15 PM

Thanks waynep for the detailed reply.

I had to tune itby ear because the engine would stall out when I got the timing mark close to the timing scale. The harmonic balancer was reading 30 deg advanced when the timing sounded correct(vac adv plugged and light connected to #1 cyl lead) I will investigate the hamonic balance and casting code further and use the info you provided. Unfortunately there is no dist. tag. Grin Thanks again!  

waynep71222 waynep71222
User | Posts: 246 | Joined: 04/12
Posted: 12/06/12
09:51 PM

do you own a 1  1/4" socket....   use a breaker bar on it.. on the big nut in the middle of the crank..

with the distributer cap off..   rotor on...   rock the crank back and forth...

how far does the outside of the damper move before the rotor starts turning ...

move the crank clockwise until the rotor turns... mark the spot on the damper.. turn the crank the other way till the rotor starts to move... note the distance..

if the damper has moved more than 1/2" before the distributer rotor starts turning the other way...   your timing chain and gears need to be changed...

the cam sprocket unless its already been replaced has NYLON gear teeth on an aluminum sprocket.. and they FAIL....  rocking the crank back and forth is a great and easy test...

warning.. some years of small block dodges will bend the valves and push rods  if the chain slips..

when the timing set goes bad.. the cam and the ignition timing will need to be reset..