Ignition timing question

[Doxerman51]

Hello all,

I have a Prestolite IAD 4114-1M Distributor on my Mopar flathead. Anyone have the ignition timing for this unit? Thanks for any help.

[Guest elmo39]

what year and make is your mopar

[Doxerman51]

Hello elmo 39,

I have a 1941 WC-12 Military 4x4 which has a 230 in it. The motor was a replacement which was in the truck when I bought it. The ID on the pad says DR0014232CAL. It had a vacum advance Distributor on it (IGS 4203-A) which I changed out for this IAD model which has centrifical advance. I can't seem to find any specifications for it. I have been told it was used on industrial applications and in mopar boat applications. Thanks for any info.

[hchris]

Dont have specific figures for a DR engine, but most of this era started at TDC and maybe went to a maximum of 5 degrees advance. With a 4x4 I cant imagine the revs would get too high.

[Doxerman51]

Hello hchris,

Thanks for the info. I'll tweak the timing alittle and see what happens. Maybe I'll just go back to the IGS distributor at least I know what the timing is for it. I just didn't like the vacum tube going across the top of the block to the Carb. I wanted a "cleaner" look. I swapped out my 4.89 third member in the rear axle for one with a 4.30 ratio. With the 900-16 tires, I can now cruise at 55-60MPH with the dirty 230 running at between 2500-2600 RPM. I plan on swapping out the front third member very soon. Boy, what a difference; now cars don't pass me like I am standing still. I plan on swapping out the 230 for a Chrysler Industrial (IND 7) 236CI also. I'll have more power and be able to rev up the longblock 236 more than the shortblock 230. I'll also put a 241CI "Spitfire" head on the 236 to dress it up some. I love old mopars. The best engineered cars of their day.

[Guest elmo39]

if its a 230 it doesnt matter if its military ,com or car the timing will be tdc the marks will be on the vibration damper and will show as either 0 or tdc the spark plug gap would be between 25-35 thou , and the points 20 thou , i think the only time the 230 wasnt tdc was if it was in a car that was fitted with fluid drive ,if you are determined to fit a long block why not go to a fifties chrysler 250 flat head .

[Guest JohnArthurSpinks]

Doxerman51,

You may find that the Prestolite Distributor was used without the Vac advance on either the industrial or marine engines as they were normally run at a more constant revs and load and had a load sensitve governor.

The vac advance on the IGS4203A had 9 degrees of automatic and 9 degrees of vac. which when travelling at a light throttle opening whilst cruising would give you say 18 degrees of advance and an improvement in fuel economy.

If for instance you opened the throttle wide to pass another vehicle or had to hold a constant speed on an incline the vac would then drop off and the total engine ignition advance would fall off towards zero and this would prevent engine 'pinking' or detonation during high load conditions.

I would say that the Prestolite unit would not give you that sort of luxury and to get the max out of your engine with the gas that you are using you would most probably have to crank more static advance into the distributor which may be ok when you start up when things are cold.

However try it when the engine is hot and you will have the symptoms of a flat battery as the engine will try to fire at the wrong timing and run backwards.

In other words the timing will be too early.

I suggest that you stick with the auto and vac advance dissy.

Cheers

John Spinks

Aussie C9 Chrysler Airflow Coupe

[Doxerman51]

Hello all,

Thanks for the advice. Elmo39, the reason I'm putting in the 236 is because it's paid for and of all the American built long blocks, the 236 has the shortest stroke of the bunch. I should be able to rev it up more if needed due to it's shorter stroke. JohnArthurSpinks, I may well put back the IGS distributor and see if I notice any difference in power or gas mileage.