1929 double a won't start, help

[Rob Doe]

Quote "Thanks for the pic, I just checked and that's exactly what I've got."

So the first picture in the three pictures posted in post #51 isn't what you have for timing? Your picture does not match the picture sent to you in post #58. Your picture is out of time a large amount.(advanced approximately 15 -20 distributor degrees which is double that in crankshaft degrees)

 

[Bob C]

You can see the one you posted is not the same as the one I posted.

 

[Danny Boy]

The rotor goes counter clockwise, In my picture the brass tab right hand edge is inline withe the #1 and the points close.
In the other picture the brass tabs left hand edge is inline with the #1 and the points are opening.

So as the rotor turns counter clockwise and the spark lever is fully up, the points are closing when the rotor comes in front of the #1 pin and after its travels the lenght of the brass tab it opens just as the brass tab leaves the #1 pin.

Basically points close when inline with the brass rotor and opens just as the rotation causes the brass tab to leave the pin. If I move the timing anymore clockwise the points would close on air before it makes contact with pin #1.

Theres a bit of play in my cam but not that mutch. I kept it tight clockwise since that's how the rotor gets pushed around. Just like I've seen people set the timing on videos with that nu hex key, "2 rotations clockwise to take out the slack".

 

[jg61hawk]

Assuming you have the timing set, and are getting spark at the plugs and your concern is the valve I would still respectfully suggest towing the vehicle several blocks in gear to get everything moving and see if the valves loosen up without any more labor / disassembly. I would leave key and gas off.

 

[nkaminar]

So, just to be clear, are the points just opening when the timing pin is in the detent in cam gear and the timing lever is all the way up?

 

[Rob Doe]

Dan, I'll remind you that the coil primary circuit's magnetic field collapses when the points open. This instantly induces a high voltage/pressure but low amperage (milliamp) current that fires (is capable of bridging the gap) at the spark plug.

In short, plugs fire when points open. Not when they close.

If when you took your picture of the rotor the pin was seated in the dimple of the timing gear:

1. Remove the rotor and loosen the distributor cam until it is loose to your finger movements. (doesn't drag the distributor shaft along with it)

2 Put the rotor back on and aim it directly at the #1 contact pin. (contact pin is centered in the middle of the rotor tab. This assures that you are at the correct lobe of the cam.)

3. Remove the rotor again, and with your fingers rotate the distributor cam counter clockwise until the point block opens the points wide.

4. Then, without letting go of the cam, move it clockwise until the points just close.

Perform 3 and 4 as a smooth single motion, pausing to see the points wide open and then just closing.

5. Lock the cam in this position by tightening the cam screw. You need a cam wrench to do this with accuracy, (they cost a buck or two) but if you hold the cam as best you can with your fingers and then tighten the rest of the way carefully, I think the position of your rotor will be as it should.

 

[Danny Boy]

So what you guys are saying is the points should close just before the brass tab hits the #1 pin?
And they should open before it leaves the brass tab, it should be just opening when centered on the brass tab?
So the spark happens when it opens?

Sorry for all the questions, I'm the kind of person who needs to understand the whole process lol.

Btw with my timing pin set I checked that my piston #1 was top dead center and I can easily feel that the valve is sticking up and open. I'm no expert but since that's the moment spark happens shouldn't both valves be flush and closed.

 

[Rob Doe]

Quote,"So what you guys are saying is the points should close just before the brass tab hits the #1 pin? And they should open before it leaves the brass tab, it should be just opening when centered on the brass tab?"

No, that is not what we're saying. You are timing the car to a specific moment in time. The question is not specific enough and would require too much explanation.

Quote,"So the spark happens when it opens?

Yes. Absolutely, yes. Replace the words "it opens" with "the points open". The coil has two independent circuits. They are not connected to one another. In fact, they are insulated to protect them from touching one another. The coil operates on the principles of magnetism and the "magic" of building and collapsing, invisible magnetic fields.

Quote, "Btw with my timing pin set I checked that my piston #1 was top dead center and I can easily feel that the valve is sticking up and open. I'm no expert but since that's the moment spark happens shouldn't both valves be flush and closed?"

At TDC on #1 cylinder, both valves should be closed completely. In fact, the two valves should be closed tight enough (sealed so perfectly) that if the cylinder were inverted and holding a small amount of gasoline, it would hold that gasoline a long while. This would indicate the valves were properly lapped in???

 

[nkaminar]

Plugs fire when point open.

Both valves should be closed when at TDC of power stroke. If not there could be a valve that is sticking or the valve latch could be way off. Try spraying some light oil that is used to loosen things, like WD-40 or Marvel Mystery Oil so that it runs down the valve stem or into the intake manifold when cranking the engine over or, better still, when the engine is running. Or, take the valve cover off and spray the light solvent oil in there while working the valves and lifters up and down by turning the engine over with the starter. A sticking valve will be obvious. Test the valve lash by trying to rotate the tappets when the valves are completely down. Make sure the cam is on the heel.

If there is an intake valve that is staying open then this could explain the backfiring through the carburetor.

 

[nkaminar]

One other point: If the piston is at TDC between the exhaust stroke and the intake stroke the intake valve will be slightly open and the also the exhaust valve. These are very slight openings so if the piston is not exactly at TDC one of the valve could be open. The engine does this to improve the breathing, providing a little lag in the exhaust valve closing and a little advance in the intake valve opening.

You need to make sure that the timing pin is in the detent to know if you are at TDC for the power stroke and not TDC for the beginning of the intake stroke.

 

[Big hammer]

In a 4 stroke internal combustion engine the piston is at TDC twice, once on the END compression stoke and once at the end of exhaust stroke when the intake valve is opening. This is where your wrong, your 180 degrees out.

With all the spark plugs out, hand crank the motor and with your thumb over #1 spark plug hole you will feel or hear air coming out, this is the compression stroke, this is when the timing pin should drop pop in ! and this is when your points should open and fire the #1 spark plug, the rotor should be adjusted pointing to the #1 pin in the dizzy cap. Go back and look at the pictures posted, the correct picture and your wrong picture of the rotor.

In your picture showing the rotor I think I see the heat shroud around the rotor, is the bottom of your distributor open broken out ?

 

[katy]

The points should be closed and just about to open?

You got it.

 

[katy]

Positive is towards the drivers side, on the right.
Negative is toward the passenger, on the left.

That coil is the opposite of Model A coils as the +Positive terminal on the Model A coil mounted wire down is on the passenger side. I have no idea how this may be affecting you but it could be a significant problem...Unless of course whoever wired it was aware of the switch...I don't mean to imply the coil matters but how it is wired does. Others smarter than me will need to address this...Somewhere on this forum are several good easy wiring diagrams...I searched quick but didn't find one I wanted....

The coil polarity won't affect whether it starts or not. It may affect how good it runs, but not whether it starts or not.

 

[Danny Boy]

Ok I think I understand, I towed it to my place this week to be able to work on it. I have a very long driveway so tomorrow with some patience I will get some help and push her for a few slow rotations and really look at the timing in detail.

I've been looking at that valve since I noticed it and I'm pretty sure it's not moving but I will make sure by rolling it over a few rotations.

Here's a dumb question, can I tap on that valve to "unstick" it?
With a rubber mallet and a hard piece of plastic so I don't scratch or chip anything.
I did add a bit of marvel oil into each chamber, added a little yesterday again.

I'm ordering that timing nu hex wrench today, should of done that a week ago

 

[Rob Doe]

The coil polarity won't affect whether it starts or not. It may affect how good it runs, but not whether it starts or not.

x2. General aviation, piston driven aircraft engines ignition systems are driven with magnetos. An aircraft magneto produces AC current to fire the plugs.

 

[Rob Doe]

Ok I think I understand, I towed it to my place this week to be able to work on it. I have a very long driveway so tomorrow with some patience I will get some help and push her for a few slow rotations and really look at the timing in detail.

I've been looking at that valve since I noticed it and I'm pretty sure it's not moving but I will make sure by rolling it over a few rotations.

Here's a dumb question, can I tap on that valve to "unstick" it?
With a rubber mallet and a hard piece of plastic so I don't scratch or chip anything.
I did add a bit of marvel oil into each chamber, added a little yesterday again.

I'm ordering that timing nu hex wrench today, should of done that a week ago

I suggest cleaning the contact pins on the distributor upper body. The Nu Rex wrench should get you back in the game. I predict that: Once you see the proper points to cam relationship from a properly timed position, the dominoes will fall over for you. Hang in there.

 

[jg61hawk]

Can you post a picture of the timing cover...I can't tell but others here will be able to tell if somewhere a Model B cover was put on...that changes the timing pin location and then that creates a real puzzle. Moving it certainly could help un stick the valve, it will move oil into the area and hopefully things loosen up. Others here could also answer. Will it run on three cylinders? I know you can leave one plug off and they run, but with the valve creating blow back would they still run? This is a good thread (maybe not for you Danny) but I'm learning a lot and printing a lot for my own notes...Thanks guys for the knowledge you are willing to share.

 

[Danny Boy]

Are you kindling me, this is a great thread. I'm actually having fun diagnosing this truck while learning alot.

When I spoke with the previous owner he mentioned having alot of trouble timing the truck.
He said he changed that distributor body with one from a mode t (in French t and b do sound alot alike so maybe I heard that wrong).
And he taught the reason was because the spark lever rod wasn't the correct length. That didn't make any sense to me because moving the lever all the way up and all the way down touches the distributor plate perfectly on both edges of the distributor body.

Now keep in mind that he also insist that the model A should be started with spark all the way down and throttle all the way down, hold choke and crank till she starts then let go of choke.
So here's some pic of it.

 

[jg61hawk]

Danny I meant a picture of the timing pin area....the pin you invert into the "dimple".

Here's is a great link to Timing Covers....more homework for you... POST your picture...

http://www.fordgarage.com/pages/timingcovers.htm

READ TO THE END. THE FINAL CONSIDERATIONS ARE EXTREMELY INTERESTING AND MAY BE YOUR ENTIRE PROBLEM...IF IN FACT YOU CAN'T SEEM TO TIME THIS. Again I need others here to tell the difference from a Model B distributor and a Model A distributor. You can probably see the difference in the covers...You brought up some new can of worms (I think) in the news the Frenchman changed something...It can and will all be overcome, it just takes time like we are doing now. Keep working Danny Boy and I'll enjoy reading!

 

[Rob Doe]

He's not right about the start procedure. As the old judge said to the jury, "The jury will disregard the previous testimony!" LOL