Position of the spark lever question

[Purdy Swoft]

Yes an engine with a stock head will knock from too much advance if lugged. Most of the roads were rough dirt trails in the model A days. People had to drive at lower speed, that is why proper use of the spark is mentioned on hills and sand beds, in the owners manual. Lead was added to the gasoline in the early thirties to reduce timing knock. Todays gas has no lead. You don't get the carbon deposits with unleaded gas but you are more likely to get timing knock than we did with the leaded 100 octane that we had in the sixties.

[hardtimes]

Originally Posted by lschultz

Well I just tried it the way ya say no advance and it started the easiest fastest it has ever. Guess I misunderstood the fellow or was not listening to much when he told me how to start it. Moved the lever down to around 8-9 o'clock after it started and it ran great. Now I noticed when I shut it down and turn off the gas it will back fire thru the muffler. Gas will drip out of the carburetor after I turn the gas off. Guess the float level is a little to high. It has died on me several times when I come to a stop.

Well, from the way that you have been using it (i.e.-backward) there will be a period of retraining your brain.
A good thing, IMO, to do until it is second nature to you...take a small card and print a few steps of how to properly start your model A ! Put it on the dash.
Also, when you are about to STOP and shut off your Model A engine...ALWAYS retard (handle up) ...let it idle a bit then shut down power and see if that doesn't help with your 'backfire' problem.

[Brobrian]

As others have said, I've alway operated my car, "up to start, full advance to run." I wonder if I advanced the timing more, if I wouldn't find the car running best with the lever at 9:00 or half-way down, as some others are doing.
It is amazing how many times I've timed my A's trying to get optimum performance out of them.
I have found that if I'm putting along at idle in either first or second gear, the car chugs less with the spark retarded. So when we go out cruising looking at Christmas lights and such I retard the spark and the car runs more evenly. Plus, I just love the sound it makes when the spark is retarded.

[Purdy Swoft]

Here is how I set the timing in my cars. Remove the spark plugs so that the engine is easy to turn, this makes the job easier. I first set the points at .022 , I then turn the engine over until I find the timing mark. Forget about where the spark lever is set or when the points open, this only adds confusion and causes most to end up with retarded timing. The important thing is where the rotor tip points. With the timing pin in the correct spot, I loosen the points cam screw and set the points cam so that the trailing edge of the rotor tip is in alignment with the number one plug wire contact in the distributor cap body, with NO clockwise backlash. If you don't have a cam wrench, it may take several tries to get it right, because when you tighten the cam screw the points cam will also try to move in the clock wise direction and when this happens it retards the timing. There will be backlash but when the backlash is in the counter clockwise direction it doesn't effect the timing. With the points and timing set in this manner it will idle with the spark up (retarded) and have that cool chick a lunka sound. when the spark is advanced the idle speed will increase and smooth out. Throttle response should be crisp with the spark fully advanced. More modern cars have vacume or centrifugal advance to prevent timing knock and buck at low speed or under strain. The model A has mechanical advance controlled by the driver and it is an aquired skill, sort of like shifting the crash box transmission. With good roads and faster driving speed that we have now days, not as much attention is needed with the spark lever as it was in the twenties. I don't creep around and lug the engine, that is really worse for the engine, than driving sixty mph and runs the risk of being rear ended. If you are driving on trails or parades you will need to retard the spark as needed to relieve the timing knock and buck. You can feel the sweet spot as you move the lever. There is no advantage in driving with the spark retarded to the point the engine loses power, this practice causes overheating and warped manifolds. It doesn't matter to me how anybody uses their spark. I just can't imagine driving my cars at highway speeds with the spark lever half way up the quadrant.

[31Tudor]

I guess you would have to think about it....if it was just up for start and then full down to drive there would be no notches in between. It would just be a toggle switch. there obviously is a reason for the inbetween adjustments.

[Purdy Swoft]

Sponsored Links (Register now to hide all advertisements)

I would think that the notches are to help hold the lever where it is set. Times have changed, gasoline has higher octane, we have better roads without sand beds and automobiles are driven at higher speeds. If you drive the back roads and momentum and speeds of 50-55 mph can't be maintained, more use of the spark will be needed. When I am driving on the open road I am moving right along so as not to be a nuisance or get ran over. If the timing is set right the car will run best with the spark fully advanced at speed. I sometimes drive trails with my strip down model A's and the spark is used more and I can enjoy the retarded chick a lunka sound. When I drive on the main roads I run with full advance. For the most part I crank with the spark retarded and drive the main roads with full advance. This has always worked for me I've still got my first model A and it still has the original babbit I have overhauled it twice in 52 years. When I overhauled it in 71, I removed the bearing shims. When I overhauled it the second time in 2007 I filed the caps for .002 clearance. The original babbit is unbroken and the oil groves are still present I have driven this engine fast since I was a teen ager and I know that my use of the spark has caused NO damage.

[BILL WILLIAMSON]

My suggestion: Folks that don't seem to master it, or don't want to mess with it, Just buy a simple Mallory point type distributor and go. Did it on Minerva, my '30 coupe, and it was like driving a different car. (I know it's not PROPER, in case my "ADMIRER" is reading this!) Bill W.

[inex01]

I have been breaking in my new Schwalm's motor and yesterday I drive over 60 miles in the rolling hills of Maryland and found that "Sweet Spot" depended on the road conditions and was able to fine tune the timing easily because you can actually feel the motor power curve as you move the lever. Retard up a hill felt like you were loosing power but is important so you do not pound the babbits, downhill retard does seem to assist in slowing the car down, but on level road you can easily get the motor into that Sewwt Spot, I also adjust the GAV vavle and keep it slightly rich durig breakin to keep her cool.

[Purdy Swoft]

Here is the Mallory dual point distributor on my daughters 31 coupe. The girls are not really in to the finer points of using the spark. Centrifugal advance will really save on starter armatures. When she was a teenager, she would sometimes forget to retard the spark when cranking. This is also a good idea because her car has a high compression head. ...

[Tom Wesenberg]

Purdy, glad you posted that picture. It's a good reminder that you should always remove rings and bracelets when working around electricity. The amps from a car battery can burn the finger off if the ring shorts it to ground.

My friend lost a finger last summer while climbing down the ladder on his cement truck. The ring got caught on something and he slipped down.

[Purdy Swoft]

Thanks, Tom. I'll have to warn her. We don't want her scared up.

[TinCup]

I have always started the car full up and then drop a couple of clicks to idle. Retard at stop signs and lights and about 2/3 down for 35-45 mph. Before I installed the HC head I would run it all the way down for higher speeds but it feels better 2/3rds down now.

[Brobrian]

Originally Posted by Purdy Swoft

Here is how I set the timing in my cars. ...

Thanks, that's sorta what I've come to practice, myself. It's great to know I don't have to worry about damaging my engine by not being more sophisticated about the use of the spark advance.

Sometimes, I like to forget all the (undoubtedly accurate) details and nuances and just enjoy the driving and tinkering.

[TinCup]

You know so much of enjoying these cars is the subtle nuances of driving them. Yes you have to listen to them, yes you have to pay attention to vibration and odors. But for me it's what makes it all so worth it.

[lschultz]

I'm reading and it's sinking in. I think good info.

[rollingsculpture]

Originally Posted by MrTube

I have to ask, with a stock "A" head is it even possible to get the engine to knock from too much advance on todays gas?

ive set and timed the dist as per instructions , and when i start up it is full retarded and at start advance to half way down while running down the road at 35-40 i have moved the advance all the way down and never heard a knock can get the old boy up to 50mph full advance does not seem to make any more diff than half-3/4 advance 42-45mph is the best performance point for the truck on the hwy. i have been wondering though how much diff it makes on the point gap and plug gaps , is it better to run points at 18 or 22 would there be a noticeable difference? also plug gap is 35 what happens if it is 32 or 37 i have been trying to see where the best responsive settings are but can only go by my own subjective observations.

[HoarseWhisperer]

Mine seems to like the smaller .018 point gap.

With stock head, .035 plug gap worked well, but I set them at .030 for the HC 5.5 head.

[theHIGHLANDER]

Ok, my take from many As in the past was always like many said, up for start and down for drive. I always thought it worked today because of our fuel quality vs the past.

On another note, has anyone ever been lucky enough or tuned well enough to start the car with the timing lever? I know that a Rolls Royce will do this once warmed up if it's dialed in. Basically you turn on the key in retard, and slowly move the lever to create a spark, next thing you know she's running. Kool as hell to see it done. Anybody? I'm going to try mine once it's up and running for good. Gotta know!!

[Keith True]

My 30 roadster will do something like that,but not quite start.When it is warm,and I shut it off,if I try it within 4 or 5 minutes it will chuff.I turn the key on,pull the spark lever down,and it will fire.The problem is that when I advance the lever the piston is not quite to the top yet.The explosion pushes the piston back down,turning the engine backwards a half turn or so.The T's are a different story.There are two that I work on that will start when warm,by turning on the key and pulling the spark lever down.Sometimes I just turn on the key,hear the coil buzz,and it takes off with a roar.There was an old man with a T that lived near me when I was little.He had bought it new,had never had a license,and had taken to driving the car through the woods to get around.My family owned all the land there,the store and gas station.He would come down the hill behind our house,through the brook,between my grandfathers house and ours,and on to the my uncles beer/gas store.Before he got his quart of beer he would set the spark lever,leave the switch on,and go in.When he came out he would give the side of the car a huge kick.The spark lever would drop and the car would light off.That car was so worn out that sometimes when a truck went by it(10 feet away)on the concrete highway the lever would drop on it's own and it would fire off on it's own.He used to do that just to make us kids giggle.

[Jerry Parr WI]

Mostly a lot of good advice. It may help to consider what a more modern fully automatic advance distributor does. It has two advance systems. A centrifugal advance that adjusts the timing based on speed and a vacuum advance that adjusts timing based on load. For starting both systems are fully retarded (lever up). As the engine speed increases the timing is advanced by the centrifugal system. As the vacuum increases the vacuum system advances the timing. At speed without heavy load the system is at maximum advance (lever down). The ideal position for full advance varies with timing setting and engine but should be just short of knocking. Loading the engine (accelerating or hill climbing) causes the timing to retard as does reducing speed. The ideal position of the lever would be to match these conditions. A running engine should almost never be at fully retarded as even at steady idle the vacuum advance should be near maximum advance.