Spark Advance

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Model T Ford Forum: Forum 2012: Spark Advance
Top of pagePrevious messageNext messageBottom of page Link to this message  By Willie Rathbone on Thursday, August 30, 2012 - 04:17 pm:

Is it sometimes normal to never have to move the spark advance from one setting ? My car starts and runs great without ever adjusting the advance without even the remote chance of any kickback. When I try to adjust it when driving, the engine runs worse both ret. and adv. Seems to have a sweet spot. Is this normal ?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Thursday, August 30, 2012 - 04:41 pm:

no that is not normal.

you should retard it when idleing, and advance it when driving. once your driving you really shouldnt have to adjust it except when you stop.

are you running a distributor or standard ignition system? its possible that you have a centrifugal advance setup in which case you wouldnt have to move the advance.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Peter Claverie on Thursday, August 30, 2012 - 04:43 pm:

A "sweet spot" is normal, although not universal. It depends to some extent on what kind of timer you're using. Every T is an individual.

On the other hand, I would suggest you do some checking on the fact that it runs best at the same setting you use for starting. That indicates your "sweet" setting is somewhere before top dead center, because no engine runs best with no spark advance. While you claim to have never had a kickback, that's something like claiming you've never had a heart attack.....yet.

It's not hard to do. Remove #1 spark plug. Fashion a wire to go in the plug hole and rest on the top of the piston. Rotate the crank until the wire is at the highest point. This may take several tries, but now you've found Top Dead Center. Chances are you'll find the crank is parallel to the floor, but again, all T's are different.

Turn on the ignition, and if a coil buzzes, you have the timing set to before TDC. Play with your spark advance until you find the point at which the coil isn't buzzing until you creep the lever down to that point. That's the absolute farthest down the lever should be when starting - preferably a bit higher.

The engine won't run as smoothly at that setting as it will at your sweet spot, but starting at that setting will someday save you an arm or a Bendix drive!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Peter Claverie on Thursday, August 30, 2012 - 04:45 pm:

P.S. Matthew is right -- all my comments presume a standard Timer & Coils setup. A distributor is another animal altogether, and I can't help you there.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Thursday, August 30, 2012 - 04:51 pm:

finding where an engine starts can be a little tricky.

you cant retard it too much or it wont start, it'll just chuff. so have to adjust your timing towards advance until it starts reliably

but if you try to drive at this setting you will have no power. which is why you have to advance it,


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Thursday, August 30, 2012 - 05:10 pm:

Willie
If you have a stock Model T ignition system your results are NOT normal nor expected.
Here is a link to an article Steve Coniff and I wrote several years ago to simply explain the design and operation of the original Ford ignition system in detail.
Model T Ford Ignition System and Spark Timing
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Thursday, August 30, 2012 - 05:18 pm:

Here are the standard instructions:


Top of pagePrevious messageNext messageBottom of page Link to this message  By Willie Rathbone on Thursday, August 30, 2012 - 06:11 pm:

Its an all stock system. I have owned several Ts and know its opperating at normal temp. and has plenty of power. I cant figure it out. Also kinda off a topic question, why does the engine hesitate briefly when I turn on my mag. powered headlights ?


Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Thursday, August 30, 2012 - 07:49 pm:

I don't find my timing control particularly critical either, one position for idling and driving, and another for hill climbing in top gear - but the coils in my car run from battery only.

"why does the engine hesitate briefly when I turn on my mag. powered headlights ?"

Probably because the headlamps draw a lot more current until they've come up to full brightness. The cold resistance of a light bulb filament is much lower than when hot. I don't know much about magneto current output but it would suggest there's not a huge reserve of power with yours.


Top of pagePrevious messageNext messageBottom of page Link to this message  By George Button III (Chip), Lake Clear, NY on Thursday, August 30, 2012 - 08:51 pm:

What is the cause of "minimal" response from the spark advance/retard lever?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Hoshield on Thursday, August 30, 2012 - 09:19 pm:

Ron ....
I glanced at your article post ... looks very informative ... I'll print it out for full digesting!

Jim ...
Which book did you get your 'page 38' above .. of the spark and fuel level controls? I bet it has lots of other informational stuff, too....

Thanks


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Thursday, August 30, 2012 - 10:05 pm:

Dennis,
I don't know what book the chart came out of. It was posted on a previous thread on this forum.
Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Thursday, August 30, 2012 - 10:10 pm:

johnh, thats about how it should work, a driving setting and an idleing setting, i bump my advance up a lil when im bookin it though.

what makes adv. minimally responsive? check the arm on the steering column, they get loose and the hole gets wallowed out, the control rod ends also wear down, all this makes the commutator barely move.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Thursday, August 30, 2012 - 11:33 pm:

Dennis,
I found the source of the chart. It is:
The model T Ford car, its construction, operation and repair; a complete practical treatise explaining the operating principles of all parts of the Ford automobile, with complete instructions for driving and maintenance; includes the most thorough and easily understood illustrated instructions on Ford repairing ever published; based on five years' experience of a Ford operator--invaluable to all Ford owners, dealers, salesmen, drivers and repair men--every phase of the subject treated in a non-technical yet comprehensive manner (1915)

You can find the whole book in many formats posted online at:
http://archive.org/details/modeltfordcarits00pagrich

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Hoshield on Thursday, August 30, 2012 - 11:51 pm:

Jim...
That's a pretty decent book! I downloaded it. I dare say, it's better than the Ford service book ...at least in explaining things. Drawings are clearer, and more informative, too. IMHO ...

Thanks!


Top of pagePrevious messageNext messageBottom of page Link to this message  By William L Vanderburg on Thursday, August 30, 2012 - 11:53 pm:

I have a 1915 edition and a 1920 edition, the chart is in both.


Top of pagePrevious messageNext messageBottom of page Link to this message  By George Button III (Chip), Lake Clear, NY on Friday, August 31, 2012 - 12:52 am:

Matthew, my timer rotates like it should and there is not a lot of play in the linkage, the holes or at the column.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Friday, August 31, 2012 - 01:11 am:

if it rotates as it should i cant imagine why your advance is not very responsive.

does the engine speed up when you advance it?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Friday, August 31, 2012 - 06:56 am:

Sounds like the timing is not set properly. You need to check the event timing for #1 cylinder with the timing fully retarded. It should first buzz the coil / make a spark at the plug when the piston has just passed top dead center and is just beginning to move downward.

I can do this by looking down the plug hole with the spark plug connected sitting on the head bolt adjacent to the #1 plug hole. If you are not as tall as me you might need an assistant to pull the crank slowly while you watch.

When you determine this is set incorrectly then you will need to bend the timer rod in order to get the initial spark setting in the correct place. Currently you have the spark way retarded I suspect.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Willie Rathbone on Friday, August 31, 2012 - 09:04 am:

I will take a look tonight Royce. The engine pulls down when I move the advance in either direction.The current setting works best for high speeds, starting, and hill climbing. Strangest thing.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank Harris from Long Beach & Big Bear on Friday, August 31, 2012 - 09:57 am:

Remember that those drawings in the book are for a new T just out of the factory. Rods get bent and no two are alike after a while. They get sloppy and move about. If you adjust everything, clean everything up and re-do, you may find out that it runs even better than it does now. Henry hid T.D.C. Very well because he wanted you to use his magneto with its semi-automatic settings. You only have to get close to the right place and it works well.

If you run on battery, the spark advance is more critical and you will have to move the spark lever for different speeds and loads.

If you are running a distributor, it may have an automatic internal advance – retard mechanism and that is why it is working well for you.

If you are using buzz coils and it starts without kicking either you are hand cranking with a very powerful pull while it is advanced to some degree, or you are using the electric starter and it starts so quickly because everything is adjusted very well and it doesn't have time to fire against the compression stroke on the up-pull.


Top of pagePrevious messageNext messageBottom of page Link to this message  By George_Cherry Hill NJ on Friday, August 31, 2012 - 10:28 am:

Willie,

There are a few T's that just start with the stick up, and run with the stick down, and get from point A to point B without overheating. FEW is the word and I've always been convinced they are mechanically set 'wrong' and just 'work'. I had an 85 year old newbie yell at me a while back because while I was checking out something for him 'gratis' on his newly acquired '27...I had the stick near the top while I pressed on the starter and it wouldn't start and just whirred! He came at me flapping arms and told me I didn't know how to start one! Put the d*mned stick at 9 o'clock, step on the starter, and she's start fine and immediately he said! It did! So I tried to explain that if that is where start was, he was running retarded all the time because he had given up about 25% of the top end too as far as advance. His answer was so what, gets him from 'a' to 'b', doesn't overheat! I've been debating this with him for over a year now without further success. It's a Fordor and just lumbers along anyway.

Do what Royce says...assumiing you are running coils and timer, mechanically 'time' everything to fire 'right', then adjust the rods to match that point with the lever fully retarded (and taped that way), and at the same time look for lost motion in the rod to clevis points. A dizzy should be set the same way but I have to tell you, the son has an original Atwater Kent dizzy on his '26 and it IS a royal pain in the butt to get set 'right'

Then and only then, if your car still has two settings only you might have one of the oddities, but then again you may be surprised at how much pep you might pick up on the top end!

Another point...can you start it on mag? If so, where is the stick? That is the tell all. Yeah I use battery source for start on all mine, even the '15, but when I have a coil adjustment, or a timer change, the tune-up for me isn't done until any of them start on mag. Personal preference, never know when that batt may be dead....lol


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Friday, August 31, 2012 - 10:54 am:

If all is set correctly you will have three distinct settings when running on MAG. Then you can operate as per the drawings shown above.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Friday, August 31, 2012 - 11:00 am:

Slightly off the original topic, but important for setting initial spark timing and easier hand cranked starting on the magneto.
Early (pre 1919) Model T's did not come equipped with a battery. The coilbox had the capability to include a battery but there is no evidence I can find Ford every acknowledged or recommended using a battery. This is probably because one of the fundamental design requirements for the Model T mandated by Henry Ford was it MUST have a self contained power source for ignition.
That said, starting instructions early Model T's is different than the instructions posted above by Jim Thode.
Here is a copy of the early starting instructions.
1
The reason for advancing the spark lever when starting on magneto is explained in the text and Figure 8 in the article in the link I posted above.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Friday, August 31, 2012 - 11:35 am:

Of course Ron's instructions for starting on the magneto are correct. Maybe two things should be reinforced, 1. The procedure is for starting on the magneto only (Ron made this clear) and 2. The timing must be set at 15.5 degrees after TDC as Ford recommended.

I'll probably never understand the reason for the initial timing of 15.5 ATDC. On one hand I would assume the reason is for safety but then they turn around and say to set the timing on the 3rd or 4th notch of advance. Kind of cancels out the safety reason. But that's another story.

Bottom line is that anyone hand cranking a car needs to know exactly how the timing is set. Willie's comment, "My car starts and runs great without ever adjusting the advance without even the remote chance of any kickback." make me wonder how the timing is set.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Willie Rathbone on Friday, August 31, 2012 - 12:17 pm:

http://s1201.photobucket.com/albums/bb350/tarheelwillie71/?action=view&current=M OV09900.mp4

http://s1201.photobucket.com/albums/bb350/tarheelwillie71/?action=view&current=M OV09883.mp4


Top of pagePrevious messageNext messageBottom of page Link to this message  By Willie Rathbone on Friday, August 31, 2012 - 12:20 pm:

Yes, the car only has a mag. No bat. Ive never had a T do this before. How do I adjust the timming ?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Friday, August 31, 2012 - 12:40 pm:

Here is one thread with ideas on setting the timing:
http://www.mtfca.com/discus/messages/179374/246966.html?1321457711

And one post from John Regan is quick and easy:
The timing mark on a T is the crank shaft pulley pin. That pin hole in the crankshaft is the reference point used when the throws on the crankshaft were ground at the factory. Every time that pulley pin is exactly horizontal (3 o'clock - 9 o'clock position) one of the 4 pistons is exactly at top dead center (TDC) - not approximately at TDC - exactly at TDC. Hence you can easily use that pin to get your timing dead on. When that pin is half way between 3 and 4 o'clock position you are at 15 degees after TDC since there are 30 degrees between 3 and 4 o'clock position. The way I do it is to pull the lever all the way up and with plugs out but connected to their plug wires and laying on the motor I then turn the switch to BAT and pull the hand crank super slow and stop instantly when I hear any coil buzz. I then simply look at the pin. So long as the pin is just past horizontal I am safe. If all the way to 4 o'clock or beyond then I am too retarded. Shorten the rod to advance the timing and repeat. It doesn't matter which cylinder you use since the pin will be horizontal every 180 degrees of rotation and a piston will be up at TDC every 180 degrees.

The link that Ron P. Posted kind of cover the whole idea behind the process.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Friday, August 31, 2012 - 01:38 pm:

The problem is, what if the car has a Sure Mike crank or a Model A crank or a '28 Chevy crank or a Chinese reproduction crank? There's no guarantee that every crank pin hole is drilled properly, so I question the use of anything other than piston position as being safe to recommend.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Friday, August 31, 2012 - 04:17 pm:

Royce,
You're correct, if not a Model T crank, then things could change. The other thing Willie would have to do because he has no battery is use a test light, ohmmeter or add a battery to know when the timer makes contact.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By kep NZ on Friday, August 31, 2012 - 05:19 pm:

You have an interesting puzzle there.
(My mag has 4 settings and the fourth one makes it vibrate terribly)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Willie Rathbone on Friday, August 31, 2012 - 07:23 pm:

Update : without moving the lever from where it has been for months, I hooked up my jump start bat. pack to Bat.terminal for the first time ever, proceeded to crank slowly and BAM it happened, my first kick back. Took off a nice streak of skin off my forearm on the headlamp door nut stud. I noticed it starts firing when the # 1 piston is about 3/16 from approaching TDC. How do I correct this ? I have never had it kick back at all with the mag. ??


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Friday, August 31, 2012 - 08:08 pm:

Willie
Please do not take this in the wrong way, it is meant to be constructive and help you with the problem you originally posted.
Your spark timing is screwed up so STOP fiddling before you seriously hurt yourself!!
You MUST correctly set your initial spark timing on battery so it will be correct on magneto.
This will also allow your Model T to perform as Royce suggested above.
You also have to check for any slop in the spark lever to timer case movement. That is one of the key points we were making in our article about original spark timing.
There is no silver bullet. Quit talking and fix it!
Jim Thode
You know exactly what is going on here. Will you please write a complete (piston travel and crank pin) set of step by step instructions to set initial Model T timing on battery and give it to Willie before he winds up in the emergency room!!!
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Friday, August 31, 2012 - 08:34 pm:

Willie,

You bend the timer rod to fix it so the spark fires when the piston is just past TDC.

First, disconnect the timer rod from the timer.

With the ignition off:
I use a plastic drinking straw to feel the piston going up. There is a bit of dwell time when the crankshaft is still turning but the piston is at the top, then you will feel the piston move downward.

Turn the ignition on:
Now see that the plug is sparking? Rotate the timer until it is counter clockwise (fully retarded) as far as it can go. The plug should stop sparking. (Note, do not ever operate a Model T coil without a spark plug connected to it! You will ruin the coil.) Then slowly rotate the timer clockwise until the spark begins.
Turn the ignition off.

That is the place the timer must remain while you carefully bend the timer rod to fit without moving the timer.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Saturday, September 01, 2012 - 12:13 am:

Willie,
Royce's instructions are good with two additions. 1. Remove all 4 spark plugs and set them on the head with the wires connected. You already found that the engine can bite you if it kicks back and you want to eliminate any chance of it firing till you know that the timing is set correctly.
2. In order to use the magneto starting method listed in "Answer No.5" above the timing needs to be set at 15 degrees after TDC. That is looking at the crankshaft pin it should be 30 minutes on the clock after horizontal (about 3:30).

Once you get it set where you think it is correct and before you install the spark plugs, do a final test to check the position it fires on each of the four cylinders. That is the pin in the crank shaft should be near 3:30 for each cylinder. Then when everything is checked you should be able to start on magneto using the "Answer No.5" method and THIS IS IMPORTANT, if you start on a battery the spark lever should be fully up or in the fully retarded position.

One additional suggestion, always start with a upward pull as in your video but only use the left hand without the thumb wrapped around the crank handle. It if does backfire your hand will likely be thrown away from the handle and out of the way when it flies back around.

Good luck,
Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Rick, Sandy Creek, NY on Saturday, September 01, 2012 - 07:05 am:

This question may be a little off topic, (and probably pretty stupid) but the thumb nut on top of one of my coils backed off when I was driving. I don't have any other good coils. I've been trying to get it working again but can't seem to get it right. Here's the question.. can I turn that nut while the car is running without getting knocked on my can? I just can't work up the courage to try.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Saturday, September 01, 2012 - 10:27 am:

The voltage on top of the coil is primary voltage (battery or magneto). You won't get shocked.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Saturday, September 01, 2012 - 10:46 am:

With magneto and coils, you will find that when you advance or retard the spark by moving the lever down or up, that it will not do much for a few notches, and then it will jump to a faster or slower speed for a few notches etc. Usually there are three or sometimes four positions where it will noticeably change speed. With some timers, when you approach the spot where it advances or retards, it will start to run rough. Possibly caused by the roter hitting on one segment for one cylinder and another segment for another cylinder. When you move the rod slightly up or down it will smooth out. This is called the "sweet spot". When running on battery, it should have no sweet spot, but when you advance the rod it should advance slightly for each notch.

It is my thought that Willie's timer is worn. Maybe the linkage is worn as well and he has found the "sweet spot" When he advances or retards it, it runs worse. If he advances it more, the worn linkage will not let him advance to the next "sweet spot".

Cleaning up the timer, or replacing the timer, re-setting the retard position, and tightening the linkage might just surprise him with improved performance.

Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Saturday, September 01, 2012 - 11:16 am:

Taking into account that if your parts are in good shape the relative positions of the spark and throttle might remain the same as shown in the above illustration but unless you have an early car with the brass quadrant the number of notches as stated will not be the same as with the pressed steel quadrant.


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