Spark-Lever Posistion

R

rfitzpatrick

Well-known member
Often read from new/old members stating their spark-lever location when they out on the road. Some do say 'full-advance' and was wondering at what speeds would that be? How often is full-advance used?

I have a '31 Pickup with a 3.78, everything stock and it's all city driving -- there's no Country-Roads any more (South Florida). I drive at no more than 50% advanced. What conditions would render the need for full-advanced?
Thanks
 
I only fully advance the spark when pushing the motor up to 50-55. In general, the faster you go, the more advance you need.
 
I have been driving my Model A in the mountains of West Virginia this week (normally I'm on flat Florida roads) and when climbing mountains found I needed to have the spark lever all the way up which is opposite than what I expected. It runs great like that but if I pull the lever down when climbing hills then the engine pings.

I'm pretty sure the engine is timed exactly like Les Andrews but I do have a 6:1 high compression head so maybe that's why. I asked a few guys around here and a couple said their cars run the same and told me not to worry about it.

Normally while driving on flat roads I never go more than half way with the lever.
 
If 10 people respond to your question....You'll get 11 different answers :D

The Instruction Book that came with the car says...

For average driving, the spark lever should be carried about half way down the quadrant. Only for high speeds should the spark lever be advanced all the way down the quadrant. When the engine is under a heavy load as in climbing steep hills, driving through heavy sand, etc., the spark lever should be retarded sufficiently to prevent a spark knock.

Those instructions give a lot of leeway. Also, no two cars are timed exactly the same, and no two cars have exactly the same wear on parts like, distributor shafts, distributor cam, points, cam shaft and cam shaft gears, etc. Also, setting points with a feeler gauge is prone to error no matter how good you think you are.

Start with the above instructions from the manual and play with the advance lever at different loads and speeds. You'll find the sweet spots. What works for someone else will not necessarily work for your car.
 
Dick's guidance is SPOT ON! Had he not pointed you to the original Instruction Book, I would have.

Remember that "high speed" in the Model A era was over 35 MPH! So 1/2 way down for chugging around town at 20-30 MPH speeds is fine. Above that speed, you can advance it to 3/4 down. At the 50-55 speed, more is good. You can advance it in small steps and feel when you get no more added power or speed. Stop at that point, or even go back a click. Every car is different; that's why Henry gave you that spark lever.

All of the above is with a stock head. A high compression head will not tolerate as much advance or it will knock (as Jim Quinlan describes). So advance a tad less, especially on hills.
 
One way to be able to get a little more advance with a high compression head (and hence a little more performance) is to use high octane gas.
 
Dick Steinkamp said:
If 10 people respond to your question....You'll get 11 different answers :D

The Instruction Book that came with the car says...

For average driving, the spark lever should be carried about half way down the quadrant. Only for high speeds should the spark lever be advanced all the way down the quadrant. When the engine is under a heavy load as in climbing steep hills, driving through heavy sand, etc., the spark lever should be retarded sufficiently to prevent a spark knock.

Those instructions give a lot of leeway. Also, no two cars are timed exactly the same, and no two cars have exactly the same wear on parts like, distributor shafts, distributor cam, points, cam shaft and cam shaft gears, etc. Also, setting points with a feeler gauge is prone to error no matter how good you think you are.

Start with the above instructions from the manual and play with the advance lever at different loads and speeds. You'll find the sweet spots. What works for someone else will not necessarily work for your car.
Click to expand...

EXACTLY!

When purchased, my car required full advance all the time. That should have tipped me off to a timing issue yet so much other stuff to do on the car. Eventually got to the proper method for timing the engine and found .008 point gap and did the Ford Method of timing the engine and bingo, My spark advance generally is a little above center and varies with speed above 35 mph. What a difference, just by properly timing the engine!
 
1929 said:
So, if you have a 6-1 Head, you should stay at half, if you are cruising at 50 or below?
Click to expand...

Follow what others say. I have a BF h.comp head and one needs to listen and "feel" the motor for the varying speeds and hills, etc. At 50, one can be at about 1/2 down or a little more, but when approaching grades, the spark rod may go up to 1/4 or whatever the engine tells you. Some cars may be more sensitive than others especially on a tight engine, and you may be adjusting the spark rod often to avoid bearing pounding and pinging.
 
I dare say that many of us old farts haven't heard a ping in years. At least I haven't. We just have to drive by the feel of it.
 
I agree with 28* max. On my car this is the lever at 9oclock. I check this with a degree quadrant for front pully. Mine is also a Rich Faluca engine, 5:1.

John
 
Benson said:
https://www.antiqueenginerebuilding.com/INSTRUCTIONS.html

Item #5 covers engine timing ... 28 degrees max with 6.0 head.

I have been using higher compression heads (Police head 5.2, Thomas 8.25, Lion Head III- 7.0) on Model As since 1962 and totally agree with 28 degrees max with Police head.
Click to expand...

Those instructions from Antique Engine Rebuilding are for ALL of their engines...not just ones with HC heads.

I wonder why Henry gave us the capability of 40 degrees of advance AND says to use it all at higher speeds??

If I was selling rebuilt engines, I might also tell customers to restrict advance. It does result in poorer performance and lower fuel mileage, but may help get the engine through the warranty period.
 
I time my touring engines the normal way, then go out on the road. At a steady 40 mph or so, I advance the timing till I hear the motor start to sound harsh, then back it off a couple of notches to where it runs smooth again. I note that position of the lever and don't diddle with it other than to start. I've found that works well regardless of what compression ratio head you are using.
 
What Synchro says.

Every engine is a bit different, but, these monsters don't need 40º of advance. If full retard is 10:00 then normal driving is 9-8:30. Full advance at 8:00 I never use.
 
Just install Ford's up-dated ignition system and be done with all the stewing over proper timing. By "up-dated", I mean the 1932 up-date: The 'B' centrifugal advance distributor! Or a modern version. See, built-in automatic advance is even period-correct!
 
Not only is a B distributor period correct,it provides correct timing no matter the engine rpm or load..why is that important? Detonation or 'ping' acts like a hammer on main bearings and that hammer is harder the higher your compression
 
I like what Dick Steinkamp said: find your "sweet spot"! I have a 5.5 Police Head. If your engine is properly timed, fine tune your ear to the engine's response at a variety of speeds and adjust as necessary according to conditions (speed, straight flat stretches, and hills); one setting is not good for all.
 
Railcarmover said:
Not only is a B distributor period correct,it provides correct timing no matter the engine rpm or load..why is that important? Detonation or 'ping' acts like a hammer on main bearings and that hammer is harder the higher your compression
Click to expand...

When using a B distributor in a model A, what do you set the "initial" timing at?

I believe a B distributor mechanical advance is limited to 8° at the distributor for a total on 16° at the crank. Initial timing on a B engine is set a 19° BTDC as opposed to a Model A that is set at 0°.

I am running a Nu-Rex Centrifugal Advance. I set my initial timing at ~5° ATDC and it is all in at 30° BTDC. The New Rex max advance is 30°.

Some on the above info is from Vince Falter's 'Ford Garage'. Good info on distributor advance.
 
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Ruth said:
When using a B distributor in a model A, what do you set the "initial" timing at?

I believe a B distributor mechanical advance is limited to 8° at the distributor for a total on 16° at the crank. Initial timing on a B engine is set a 19° BTDC as opposed to a Model A that is set at 0°.

I am running a Nu-Rex Centrifugal Advance. I set my initial timing at ~5° ATDC and it is all in at 30° BTDC. The New Rex max advance is 30°.

Some on the above info is from Vince Falter's 'Ford Garage'. Good info on distributor advance.
Click to expand...

Using an A cover I set the rotor dead center of the contact,just to get it running..I have a timing pointer and marked degrees on my crank pulley with a printed degree wheel,set the initial TDC mark with a dial indicator,head off.Once I get it to fire I use a timing light to dial it in.the B maps out at 10 degrees per thousand rpm advance when operating effectively,I set mine at 5 degrees at idle..I marked out 10 degrees and 24 degrees,rev the engine with the light on and cheapie tach dwell meter installed,and its hits the marks dead on with corresponding rpm.Its hard to describe how smooth the power is during acceleration,its amazing the difference against manual spark control.My engine is modified,late B cam ('C' grind) winfield head,stromberg 97,header,on a stock A crank and babbit..I did the B distributor for two reasons,performance and protection,the more power you push the greater the effect of detonation.
On a stock model a engine manual timing is a skill,and there are those who rightfully pride themselves on their ability to set their timing dead on by feel.In 1932 Ford introduced the 'new and improved' 4 cylinder engine,combining all (except the counterbalanced crankshaft,that came later in '32) things learned during the A run..the same engineers who brought you the A engine set a mechanical advance distributor as one of their first improvements.
 
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