Hi, Ive got a 53 flathead and she recently died on me and lost all spark. I've since replaced points, condenser and coil. The dist. is well grounded, and the coil is getting about 2.9v from the ignition (could be my issue, but still won't spark if I wire the coil directly). Any ideas would be greatly appreciated, I'm 20 so I don't have too much experience on these old engines. Initially the problem was intermittent, but seems to not work at all now.
Have tried the wire that goes from the coil to the points? It may be moving and grounding the points out. Either way it sounds like a loose wire someplace. Mike
First, did you adjust the points with the rubbing block on the arm on the points at the tip of of one of the lobes on the distributor cam? Blue arrow on the photo below, that block has to be exactly on one of those tips before you adjust the gap (red arrow) and yes I know that this is a chebby 216 distributor but it is what I have used for this conversation for years. Next, back when I was 16 and had my 51 Merc and decided to change the points I got either the wire from the condenser and maybe the strap from the points on the wrong side of the insulator block inside the distributor and that didn't let the ignition complete the circuit. and allow the coil to do it's thing. The coil builds up a magnetic field when the points are closed and there is power to the coil. When the points open that field collapses sending a high voltage charge from the secondary winding out the coil tower to the distributor cap, rotor and then to the plug wires. The condenser is the shock absorber for the voltage that is going through the primary winding of the coil to the points so the voltage can dissapate to ground and not jump the points.
There is a ground wire under the points plate that fails very often. It is not visible until you remove that points plate.
2.9 volts to the ignition is not enough, maybe your ignition switch is bad. You may have more than one problem here. First you need 6 volts at the coil, and go from there.
Here's some info I posted almost ten years ago that should help you to better understand the operation of points type ignition systems and how to troubleshoot them. https://www.jalopyjournal.com/forum/threads/hot-rod-technical-library-basic-ignition-systems.983424/ This all applies clear back to 1953 and then some!
Make sure you start checking with a fully charged battery and clean, tight connections. That is still a positive cable to ground car, opposite of today's cars. Make sure the ground is clean and if it is attached to frame ,move it to block and add an additional ground to frame .
I hear some people run "ballast resistors" to lower the voltage though, could my car possibly have that? and that's why the voltage is lower.
I doubt a big ground issue like this, simply because the car is cranking over great. does that make sense?
Did this for the points and checked the condenser wiring placement so it should be good. thanks for the taking the time to explain I actually didn't know what the condenser did.
Are you running a 6 or 12 battery? Positive or negative ground? 6 volt ignition systems don't typically require a ballast resistor. If you find a ballast resistor in the primary coil wiring, bypass it at least temporarily until you figure out what's causing your problems.
To start with, 2.9 volts is very low. You need to connect a jumper wire to the coil and take some measurements. I'm assuming you are on a 6 volt system. With the jumper wire attached, you need to check voltage at the other coil terminal. With the points open it should be 6 volts, with the point closed it should be 0 volts If the voltage stays at 6 volts with the points closed, there is a problem with either the wire going to the points or the ground of the breaker plate or the points are extremely dirty. To check the ground at the breaker plate, leave the jumper wire on the coil, connect one lead of the voltmeter to a known good ground, then place the other lead on the breaker plate. The voltmeter should read no more than 0.1 volts. If the ground is missing, the meter will read between 0.5 volts and 6.0 volts. How high it reads is dependent on how bad the ground connection for the breaker plate is. With no ground it will read 6 volts. If the voltage is 0 volts with the points open, the wire between the coil and the points is shorted to ground or the coil has an internal short to ground.
Have you sanded the points? Sometimes they can look perfect and still have corrosion on them, it has happened to me even with new points.
On using a meter to check the breaker plate ground, I failed to mention that the points need to be closed.
If it's cranking ok, run a temporary jumper wire from battery negative terminal over to coil terminal, not the terminal going to distributor, but in place of wire from key, if it runs ok now, work backwards through wiring to find voltage drop. I believe Ford started using ballast resistor in 1956 with 12 volt system.
So I've given it a little more testing and this is what I've found. I fixed the coil power wire, so it's getting 6 volts now. The issue is however persisting, the whole system works if the distributar clamping bolt is loose, but if I tighten it the spark disappears, needless to say I'm utterly confused.
So I've been chasing a no-spark condition on my '53 8ba-ish flathead, and I noticed the ignition system works fine it the distributor bolt is either absent of loose. but if i tighten the distributor down, my spark disappears. any ideas what could possibly cause this?
It sounds like you have a dead short problem. Check your wiring as it enters through the bottom point plate. Check your condenser and points wire connection and above all check the wire (under) the advance plate. This wire is not visible without removing that plate and that wire fails quite often.
Now you have to figure out if tightening the bolt causes a short or an open. Check the voltage at the points connection with the points open and the bolt loose. It should be 6 volts. Now tighten the bolt, the voltage should stay at 6 volts. If it goes to zero (or close), tightening the bolt is causing a short to ground. The problem has to be in the point or condenser wires inside the distributor. You need to watch them closely as you tighten the bolt. If that test comes out okay (not change in voltage), check the voltage at the points connection with the point closed and the bolt loose. It should be close to zero. Now tighten the bolt, the voltage should stay close to zero. If it goes to 6 volts or close, the problem is the ground connection between the breaker plate and the distributor body. I suppose it could even be between the distributor body and the engine block. You can test to see which one by leaving the voltmeter connected and running a jumper wire between each point and ground. I'd try the distributor body to a good ground first. If the voltage drops back to zero volts, the problem is between the body and ground. If it stays at 6 volts during this test, run the jumper between a good ground and the breaker plate. If it drops to zero, the problem is between the breaker plate and distributor body.
I vote for the little wire that runs under the breaker plate. It's not visible without removing the plate but you can fish a new wire under it using a piece of mechanics wire with a hook on one end. The insulation on this short wire was sketchy and the cause of many problems after lots of years and use. Also check the insulator block on the distributor where the wire from the coil enters the distributor body. Wire from the coil - outside the body, wire under the plate to the points - inside the body. No ballast resistor on this car. If there is one on a 6 volt coil ('49 - '55) remove it and throw it away. Try replacing the condenser. It may have an internal short. The condenser serves only one purpose. It acts as a "shock absorber", if you will. It absorbs excess high tension voltage and keeps the points from arcing and burning. It will run without one but the points will quickly fail. New ones can be bad right out of the box these days so keep that in mind. Check all connections for tightness and corrosion. Start at one end of the wiring and work your way toward the points. The point where you no longer have 6 volts to the points (open) is where the problem is. This is a simple system and careful examining should easily show any flaws. Good luck.
One more thought: You said you can get spark by loosening the distributor clamp. To me that indicates that the points are not opening and the distributor body is making and breaking contact instead of the points opening and closing. By messing with the hold down clamp you have probably disturbed the timing, too. Setting the points in these is a fiddly process unless you know the tricks. So here is the way to keep from pulling your hair out: Make absolutely sure the rubbing block on the points is exactly on the high point of the cam on the shaft. Then loosen the two hold down screws on the points ONLY enough to be able to move the stationary point by sticking a small screw driver into the slot(s) on at the end of the stationary point. You want it to be stiff to move and no looser. With the cam on the high point, twist the screw driver in the slot to set the points to .017" gap. Tighten the hold down screws and recheck the setting. The screws can change the setting when tightening and drive you nuts so don't loosen them too much, Only enough to be able to get the thing to move when adjusting. May still take a couple of tries but must be exact. You will need to adjust the timing since the distributor may have moved when you loosened it. Clean off the crud on the crankshaft pulley and look for the timing marks on it. Clean the pointer that comes out over the pulley. The pulley will have a series of marks on it. The long mark means the #1 cylinder is at top dead center and the shorter marks are degrees of advance or retard. Hook a timing light to the number 1 spark plug (passenger side front) and start the engine and let it idle. Loosen the clamp bolt. Aim the light at the crank pulley (watch out for the fan) and rotate the distributor little by little until the pointer is 4 degrees (short marks) before the long mark gets to the pointer. Crank turns clockwise from your view point. Hold it here and tighten the clamp bolt. Recheck. Long winded reply, I know, but I have to assume you've never done this before. I hope it helps you.
I used to know a genius who was very proud of his "ability" to set the points gap by eye. Among his many other self declared talents. We will call him Dave, because that is his name. One day I get a call from another friend" "Need your help, my truck won't start". 1964 F-100 292 Y-block. "What did YOU do to it ?" I ask. "Dave and I did a tune up, now it won't start." "Get Dave to fix it." "He left." Great guy. Creates a problem, then Bails. So I go over there, with my Dwell Meter and Feeler Gauges. "Who changed what ?" "Dave changed the points, I did the cap and wires." Now I know where to look. Connect meter, spin it over. Reads ZERO. Never seen that before. Pull the cap, points gap looks good. Check with gauge, only off by .002". Not terrible. HMMMMMMM. Twist the advance mechanism.... the gap gets BIGGER. He set the points gap on the bottom of the cam lobe, not the top ! Points never closed. Set the gap correctly, it fired right up. Lesson leaned ? No, he still let Dave work on his stuff. Same guy, different truck, I am helping him change spark plugs. I am doing the drivers side. #1 plug is loose... Strange. #2 is loose. All 4 plugs on the drivers side were loose. "Did you already loosen these ?" "No." "Who installed them last time ?" "Dave did." JFL.
So I got out there with my meter and followed y'alls advice. what I found was that the baseplate must have somehow been shifting from what I'm guessing is upward pressure from the dizzy shaft. So everytime I would bolt it down, the baseplate would shift, and it would completely mess up the adjustments I had just done on the points. So all to say, I just readjusted the points with the dizzy properly bolted down instead of taking it out, and the problem was solved! She's running like a charm now. Thanks everyone for all the electrical advice, it really isn't my strong suite so couldn't have done it without y'all.
Congratulations on your success, but I'm sorry to say there is still a problem. Something is either worn or loose and will come back to bite you in the ass down the road. I'd try to figure out what it is before that happens.
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