Position of spark control

[Bluejeepnut]

I have had to rework the ignition system on my 1924 Maxwell. Is the spark retarded when the control is all the way up (to the left) on the quadrant? This would pull the distributor all the way in toward the engine block.  Thank you.

[C Carl]

Vice-versa. I have never known a car which did not follow convention.Clockwise (up)  = advance. Ancient very low compression cars running on modern much higher octane gasoline should set the timing ahead of stock spec. On your car I would try setting at least 6 - 8 degrees advanced to begin with. DON'T FORGET TO FULLY RETARD THE SPARK WHEN STARTING. This should be done whether using the starter or ESPECIALLY the hand crank. (You probably know, but always pull up on the crank with your thumb out of the way to fire the engine - again  : SPARK FULLY RETARDED). Retarding the spark when driving at very low engine rpm is also a good idea. Try it. You will see that the engine runs smoother. Sometimes by using this technique, you can avoid having to down shift under certain light throttle conditions. Can you show us some pictures of your Maxwell ?  -  Carl 

[cahartley]

Carl........you never drove a Model T?....... 

Spark lever is on the left.

11:00 is fully retarded and 7:00 is fully advanced.

I'll admit it took a little getting used to....... 

[Bluejeepnut]

On the Maxwell, the lever would be at 12 o’clock retarded and 4 o’clock advanced.

 

 According to the manual, the timing is set when number one piston has travel over dead center 3/64” as observed through the spark plug hole. This is supposed to be 10 degrees past center — the full retard setting. Without any timing marks, how would one determine 6 to 8 degrees advanced? 

[C Carl]

That is very good info for myself, and anyone else not familiar with a "T". My bucket list includes driving one. In a way, I believe that experience is essential to a well-rounded old car addicts understanding of the times and technology. So many built over so many years. Having driven an "A", and really loving them, (they are the only ancient cars I ever see out in the Western wide open spaces putting on lone-wolf distance - great parts availability and support), I am tempted by most of the ones I see for sale. Looking to swap driving experience with my '24 and/or'27 Cadillacs. Any other bassackwards spark controls?  Thank you, Craig ! A -  Carl

 

P.S.  Please give me another call when you are up burning the midnight oil. I am using the 206-790-6912 number these days.

[C Carl]

Here is what I would do. Given that NUMBER ONE  : somehow you can distinguish exactly 3/64" from top dead center of piston travel through the spark plug hole, and NUMBER TWO  : that represents 10 degrees of crankshaft rotation, I would make a reference mark both 10 degrees before and after tdc. Split the difference, mark THAT as TDC, and time so as TDC coincides with full retard rather than full retard being10 degrees after. 6-8-10-12 degrees advance running on 87 octane gasoline over the 40 and change octane as it was in 1924 is probably still pretty conservative. You will have more power, cleaner, fuller combustion, and happier exhaust valves. When driving, jockey the spark control. From a stop, use full retard at, and just off, idle, and quickly run up to full advance as you slowly accelerate. Find the conditions where setting full retard at low rpms smooths out lugging. Again, this will be during extremely light throttle. You will still have to down shift if you need to use more "go pedal". But this little trick is the closest thing to an automatic transmission your car will ever have. It makes my 314 cubic inch V8 Cadillacs with 5 1/8" of stroke and 4.5 and 4.7 : 1 compression ratios more tractable in slow going.

 

Always use the lowest octane fuel available in your region. And use every opportunity to reduce intake temperature. Your car was designed to use a "polluted" gasoline which came into use around the mid-'teens, and continued throughout the'20s. It contained large amounts of the lighter fractions of kerosene, probably up to around C-12 or so. This required extremely high intake temperatures. You can compare similar engines in the 'teens. Earlier otherwise almost identical engines did not have any exhaust heated intake whatsoever. By the later 'teens, these same engines made "ovens" out of the intake. Block off, and also try to break or isolate any physical contact possible to the exhaust manifold to intake manifold connection. Insert an insulating block between the carb and intake manifold. Very, very, VERY little C-12 in modern gasoline. This above paragraph is fairly well known information,  BUT it does bear repeating from time to time. 

 

Good luck, Bluejeepnut !    Please let us know how you get on with all this.  Your forum friend,   -  Cadillac Carl 

 

 

[hchris]

17 hours ago, Bluejeepnut said:

I have had to rework the ignition system on my 1924 Maxwell. Is the spark retarded when the control is all the way up (to the left) on the quadrant? This would pull the distributor all the way in toward the engine block.  Thank you.

 

From the owners manual - to retard move the steering quadrant lever anti clockwise, to advance lever moves clockwise.

[RAH]

Why do you guys like to make things more complicated than necessary? Since there seems to be no 'Standard' in automotive engineers over many marques and vintages all you need to do is remove the distributor cap and check the direction of rotation of the rotor. Now get in and move your 'Spark timing lever' to one extreme and see which way the distributor housing moved. If it moved in the same direction of rotation then you have RETARDED the spark. If the distributor housing moved counter to the direction of the rotor you have ADVANCED the spark. Period end of story! Keep it simple. 

[Rusty_OToole]

Later Chrysler made flatheads have a pipe plug in the head, over the #6 piston. Take out the plug and drop a screwdriver or wire down the hole to measure piston height. Caution, do not use a plain wire bend it into a T shape so it can't fall in. Since Maxwell was the ancestor of Chrysler I wonder if they had the same feature?

[Spinneyhill]

Dodge 8 did.

[jan arnett (2)]

I like a dial indicator

 

[Akstraw]

On July 22, 2018 at 3:09 PM, C Carl said:

Vice-versa. I have never known a car which did not follow convention.Clockwise (up)  = advance. 

 

On my '14 Maxwell, up is retard, and down is advance.

 

 

[C Carl]

Unambiguous evidence that I have not known enough cars. I wonder when "conventional" became conventional  ? "Conventional" is very logical, and offers handy tactile feedback while driving. I am in the habit of occasionally verifying proper position of hand throttle (1 o'clock), and spark control (11 o'clock), while driving. Just find my left hand automatically giving a gentle squeeze to  bring the two close together above the horn button. I don't have to think, or look. The self-propelled hand sometimes shows me my unintended negligence. Do you know when Maxwell changed ?    -   Carl 

[jp928]

Up and anti-clockwise also require knowing which side of the steering column the control is on, dont they? My 26 Rover's control is on the right side, and Up, anti-clock is retard.

jp 26 Rover 9

[Bluejeepnut]

Hi guys,

 

Thank you for the education. On the Maxwell, the quadrant is on the right side of the steering column. So, lever up is retard and down (clockwise) is advance.