Car will not start , have good flow of fuel to carb, installed new coil, condenser and checked points and timing. I have spark to points and to plugs (All cylinders) engine will not fire at all. I fear that I have either a blown head gasket or intake manifold gasket. Any suggestions would be welcomed. I am not aware of any test other than visual to determine if a gasket problem.
Car will not start
- Thread starter Kentmac
- Start date
Marshall V. Daut
Well-known member
Check to ensure the intake manifold ports are sealed or else fuel will not be sucked up into the cylinders. Remove #1 spark plug and either spray some starter fluid into that cylinder or dribble some fuel. Replace the spark plug and start the engine. If the engine tries to start with a couple pops, that probably indicates a leaking intake manifold gasket. Use ONLY the copper gaskets with the gland rings in the exhaust ports. Other gaskets don't seal worth a darn or blow out easily. If the exhaust manifold will not seat against the engine block in the rear, the manifold is probably drooping and must be replaced. A very common problem with exhaust manifolds that are 95 years old.
Marshall
Marshall
Phil Brown
Well-known member
Usually, a bad head gasket affects one or two cylinders only, and almost all of the time the engine will run just not well. You said that you have spark to the plugs but is it at the correct time ?
Ordsgt
Senior Member
I know this sounds strange. I had someone with a similar problem and the car would not fire. A couple of days before it was running fine. I checked everything and it had fuel, spark, and compression. The problem ended up being his fuel. I drained some out into a cup poured it out on the ground and it would not light with a match. It was not smelly like old gas but not like good gas either. Drained tank new gas and it was fine
rotorwrench
Well-known member
Arcing at the points doesn't tell you whether the high tension is getting to the distributor cap. A person really should find a good way to check for spark between the distributor cap and the block. That will insure high tension at least to the top of the spark plug. Choking the carb should get a fuel dribble out the inlet pretty quick after a revolution or two of cranking. The GAV should be in adjustment unless a person cranks it off after shut down. I usually just leave it like it is on my Tillotson carb. Fuel blockage or contamination is a problem on crusty tanks.
Do the easy things first when trouble shooting. Do the harder things only when the easy ones don't hit pay dirt.
Do the easy things first when trouble shooting. Do the harder things only when the easy ones don't hit pay dirt.
Marshall V. Daut
Well-known member
"I would think that the car would start even with bad gaskets. Am i wrong?"
Manifold gaskets: I recently installed a manifold set on a Model A engine that was in a box with other parts accompanying an unfinished amateur restoration. I used new copper gaskets with gland rings. The engine refused to start. After laboriously checking the usual suspects with no success, I used a 0.010" feeler gauge between each manifold runner and the gaskets. I couldn't get it between the exhaust manifold, but it slipped up easily between the intake and the engine block. I incrementally tried thicker feeler gauges until the 0.025" wouldn't squeeze in. Apparently, someone had put two manifolds together, whose intake had been on a set that had been trued so that the intake manifold runners were about 0.025" short of sealing against the engine block. I swapped that manifold set with a known good one and viola! The engine started right up. So, in this case the gap was too wide to allow gas to be sucked up into the cylinders. The intake manifold must have a good seal in order to start the engine and have it run properly.
Head gasket: On a cross country drive with a Riley two-port OHV conversion, the engine kept blowing out head gaskets. Before I reached my destination 1500 away, I had changed head gaskets twice alongside the road in the desert between Arizona and Kansas. NOT an easy job with a heavy OHV conversion, believe me! Anyway, the third head gasket began to blow out one cylinder at a time until I had only two functioning cylinders left when I needed to stop for gas. Surprisingly, the engine started on the back two cylinders and ran that way (albeit slowly) for the next 20 miles before the third cylinder blew out. Limping along on one cylinder like an old-time hit-and miss engine, I made it to the next town just as the final cylinder blew out. The engine would not start then. So, in this case, a bad head gasket would not allow the engine to start, but it did on two cylinders. 'Dunno if it would have started on one cylinder. I doubt it.
Marshall
Manifold gaskets: I recently installed a manifold set on a Model A engine that was in a box with other parts accompanying an unfinished amateur restoration. I used new copper gaskets with gland rings. The engine refused to start. After laboriously checking the usual suspects with no success, I used a 0.010" feeler gauge between each manifold runner and the gaskets. I couldn't get it between the exhaust manifold, but it slipped up easily between the intake and the engine block. I incrementally tried thicker feeler gauges until the 0.025" wouldn't squeeze in. Apparently, someone had put two manifolds together, whose intake had been on a set that had been trued so that the intake manifold runners were about 0.025" short of sealing against the engine block. I swapped that manifold set with a known good one and viola! The engine started right up. So, in this case the gap was too wide to allow gas to be sucked up into the cylinders. The intake manifold must have a good seal in order to start the engine and have it run properly.
Head gasket: On a cross country drive with a Riley two-port OHV conversion, the engine kept blowing out head gaskets. Before I reached my destination 1500 away, I had changed head gaskets twice alongside the road in the desert between Arizona and Kansas. NOT an easy job with a heavy OHV conversion, believe me! Anyway, the third head gasket began to blow out one cylinder at a time until I had only two functioning cylinders left when I needed to stop for gas. Surprisingly, the engine started on the back two cylinders and ran that way (albeit slowly) for the next 20 miles before the third cylinder blew out. Limping along on one cylinder like an old-time hit-and miss engine, I made it to the next town just as the final cylinder blew out. The engine would not start then. So, in this case, a bad head gasket would not allow the engine to start, but it did on two cylinders. 'Dunno if it would have started on one cylinder. I doubt it.
Marshall
nkaminar
Well-known member
Interesting story, Marshall. Yes, you do need compression to run.
Regarding the manifolds. Anybody who is putting manifolds on a car should check for them being flat and in the same plane. The proper way to fix this is to put the manifolds on a mill and machine them flat and in plane. This is, of course, after bolting them together. I have fixed this problem with a sheet of emery paper glued to a flat block of granite, but 0.025 is a lot to remove using this method.
The fit of the intake manifold to the engine would be a good thing for Kentmac to check. But he said that he tried putting gasoline in the cylinders without avail. He can do a quick check of the compression by turning the engine over by hand with the hand crank. If no resistance, then no compression.
Regarding the manifolds. Anybody who is putting manifolds on a car should check for them being flat and in the same plane. The proper way to fix this is to put the manifolds on a mill and machine them flat and in plane. This is, of course, after bolting them together. I have fixed this problem with a sheet of emery paper glued to a flat block of granite, but 0.025 is a lot to remove using this method.
The fit of the intake manifold to the engine would be a good thing for Kentmac to check. But he said that he tried putting gasoline in the cylinders without avail. He can do a quick check of the compression by turning the engine over by hand with the hand crank. If no resistance, then no compression.
I was able to do a compression check and all 4 cylinders checked out at 40. I ran the test twice with two different gauges and got the same results. I removed the intake/exhaust manifold and the gasket was in poor condition. I will take the combined manifolds out to get them resurfaced and see what happens.
I cannot express the appreciation I have for everyone's input and suggestions. I will give another update as soon as I get it back together. Kent
I cannot express the appreciation I have for everyone's input and suggestions. I will give another update as soon as I get it back together. Kent
Fullraceflathead
Well-known member
With that low of compression in each cylinder I'm beginning to wonder if the timing gear has slipped.
rotorwrench
Well-known member
With 40 psi readings it indicates the engine is getting a little tired. To check the rings, a person can squirt some oil in each cylinder and retest. If compression improves then it indicates the rings are getting worn. Leak down testing will check valves and rings for leakage. More average readings for model As with some miles on them would be between 55 and 65 PSI. At least the old engine has consistent readings between cylinders. They can still run at 40 psi but they wont have as much power.
Those that have high compression heads may get higher readings than average but we aren't talking about a very large change in compression ratio between 4:1 and 5 or 6:1. It will make a difference though.
Valve timing can be checked while the manifolds are off in case it does have a timing gear problem. The intake will start to open just after TDC on the beginning of the intake stroke and the exhaust should be opening at the beginning of the exhaust stroke. A check for sticky exhaust valves can also be done since a person can see all the exhaust valves through the ports. Both valves should be closed on the compression stroke.
Those that have high compression heads may get higher readings than average but we aren't talking about a very large change in compression ratio between 4:1 and 5 or 6:1. It will make a difference though.
Valve timing can be checked while the manifolds are off in case it does have a timing gear problem. The intake will start to open just after TDC on the beginning of the intake stroke and the exhaust should be opening at the beginning of the exhaust stroke. A check for sticky exhaust valves can also be done since a person can see all the exhaust valves through the ports. Both valves should be closed on the compression stroke.
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Phil Brown
Well-known member
A couple of bolts and the little side timing cover will be off. turn the motor over by hand and look at the timing gear teeth. Worth a look
Synchro909
Well-known member
A couple of bolts and the little side timing cover will be off. turn the motor over by hand and look at the timing gear teeth. Worth a look
To check whether the timing gear is stripped, there is no need to undo anything. Take the top off the distributor and watch the rotor as you crank the engine. If the rotor does not turn, the gear is stripped. Simple!
Marshall V. Daut
Well-known member
"To check whether the timing gear is stripped, there is no need to undo anything. Take the top off the distributor and watch the rotor as you crank the engine. If the rotor does not turn, the gear is stripped. Simple!"
Yup. Even easier way to check for a stripped timing gear - If you press on the starter rod and the engine spins over much faster than usual, almost 100% of the time that test reveals a stripped timing gear. Less likely, however, would be a stripped distributor drive gear or sheared pin. But a fiber timing gear will give up the ghost sooner than that steel drive gear will. No distributor shaft turning = stripped timing gear, as Synchro909 writes
Marshall
Yup. Even easier way to check for a stripped timing gear - If you press on the starter rod and the engine spins over much faster than usual, almost 100% of the time that test reveals a stripped timing gear. Less likely, however, would be a stripped distributor drive gear or sheared pin. But a fiber timing gear will give up the ghost sooner than that steel drive gear will. No distributor shaft turning = stripped timing gear, as Synchro909 writes
Marshall