Ignition timing

June J
Technician 3rd Grade
Technician 3rd Grade
Posts: 330
Joined: Fri Jun 18, 2010 6:27 am
My garage: 1942 Dodge WC 53
1941 Willys MB
1960 M38A1 Nekaf
Location: New Zealand

Ignition timing

Post by June J »

Hi folks,
A buddy of mine has a CCKW that he is restoring. He now has the engine back in chassis and was asking if the ball embedded in the flywheel is the ignition timing mark or the TDC mark?

What is the factory setting for timing, and what is an "ideal for 91 octane gasoline.

Thanks

Ian
1942 Dodge WC 53
1941 Willys MB
1960 M-38A1 Nekaf
motto
Technical Sergeant
Technical Sergeant
Posts: 1024
Joined: Sat Apr 17, 2010 4:25 am
My garage: Harley Davidson 42WLA, Dodge WC63, Dodge WC57, Chevrolet 1-1/2 ton 4x4. Originally an Earth Borer, Pole Setter. Drilling rig gone and truck now mounts a #7 Set Lifting Frame. i.e.: Light Wrecker.
Location: 70km from Melbourne Australia

Re: Ignition timing

Post by motto »

According to the TM, initial timing is 5 degrees before upper dead centre which is where the steel ball is situated. This is done with the manual adjustment or octane selector in mid position. The TM then states that the final setting is determined by test driving and adjusting so as detonation or pinging occurs at low speed under full throttle.
My experience is that the octane rating of the fuel today is so high and the engine compression ratio so low the forgoing test is meaningless. Some people are of the firm opinion that using a vacuum gauge and adjusting the timing to a point that coincides with the highest vacuum gives optimum performance. That is something I have not determined.
Initial timing gives good results and you can decide yourself where you take it from there.

David
Ian Jamieson
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Joined: Tue Jan 09, 2007 1:43 am
Location: New Zealand

Re: Ignition timing

Post by Ian Jamieson »

Thanks Dave
1942 WC57 Command Car
1942 WC-53 Carry-All
1941 Willys MB