air sucking problem

[jan quaak]

My 60 hp engine from my ford won't suck air trough the left hole under the carburateur the right hole sucks air but the left sucks no air what can that be
so the engine runs only on a few cilinders?

[alanwoodieman]

bad intake gasket, stuck valve or valves would be most logical

[tubman]

There have been a couple of cases where the exhaust gas has burnt a hole through from the manifold heating passages to the throttle passage creating a massive vacuum leak. Pretty uncommon, but when stuff gets this old, anything can happen.

[rotorwrench]

If compression checks are good on all eight, I'd have a look at the manifold.

[JSeery]

On something that bad you wouldn't even need to do a true compression test. Just remove the plugs and put a thumb over each sparkplug hole and see if that cylinder is pushing air out on the compression stroke.

[jan quaak]

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I have tested the compression with a tester and i had on every cilinder aproximaly 4
so the compression is ok on every cilinder

[jan quaak]

so tomorrow i remove the minifold and inspect it

[Flathead Fever]

Did the engine sit for awhile? It might have a stuck open intake valve. That will disrupt the flow in the intake to the other cylinders. It really messes with an engine. The piston is pushing air back into the intake and screwing up the flow to the other cylinders. It would also probably have a fairly loud lifter noise if it an intake valve were stuck open.

My 82 year old dad has a 8BA powered, '32 roadster (see photo) that has sat in his garage for years and years. It ran perfect when it was last driven. It was probably ten-year's or more since it was last started. The fuel was so old that new fuel would not flow through the metal fuel line, it turned solid inside the tube. I can't even get a welding rod to go in the tube. I gave it an alternative fuel supply and got it started. One lifter is loudly hammering away and it will barely run. Its a unique sound, it sounds like its running on 4-cylinders but its a different sound than if you just had 4 cylinders not firing. I'm positive an intake valve is stuck open. One of these days I'll pull the intake off and unstick the valve.

They took away dad's driver's license because he refused to try and control his blood sugar. Apparently eating a tub of ice cream a day is more important than being able to drive. If he could drive I'd fix the car.

Diagnosing.

First thing to do is put a vacuum gauge on it when its running. Any valve problems and that gauge needle will be jumping.

When you do a compression test make sure to have the throttle open so the air can get sucked in past the throttle plate.

Pull all the plugs and pressurize each cylinder on top dead center of the compression stroke with a rubber tipped blow gun. If the air comes out the intake you have an intake valve problem. If It comes out the exhaust you have a exhaust valve issue. If it comes out the oil breather you have bad rings or a hole in a piston. If it comes out the next door cylinder you have a blown head gasket. If it comes out the radiator you need go get a box of tissues to wipe away your tears.

Before bore scopes we use to also have what we called the "dipstick test" at work. If you pull the spark plug and can check the oil through the spark plug hole with your dipstick, it fails the "dipstick test". Your valve went through your piston. This was a real test. It saved us from wasting time pulling the engine apart. We then ordered a factory rebuild.

[flatford8]

Originally Posted by Flathead Fever

Did the engine sit for awhile? It might have a stuck open intake valve. That will disrupt the flow in the intake to the other cylinders. It really messes with an engine. The piston is pushing air back into the intake and screwing up the flow to the other cylinders. It would also probably have a fairly loud lifter noise if it an intake valve were stuck open.

My 82 year old dad has a 8BA powered, '32 roadster (see photo) that has sat in his garage for years and years. It ran perfect when it was last driven. It was probably ten-year's or more since it was last started. The fuel was so old that new fuel would not flow through the metal fuel line, it turned solid inside the tube. I can't even get a welding rod to go in the tube. I gave it an alternative fuel supply and got it started. One lifter is loudly hammering away and it will barely run. Its a unique sound, it sounds like its running on 4-cylinders but its a different sound than if you just had 4 cylinders not firing. I'm positive an intake valve is stuck open. One of these days I'll pull the intake off and unstick the valve.

They took away dad's driver's license because he refused to try and control his blood sugar. Apparently eating a tub of ice cream a day is more important than being able to drive. If he could drive I'd fix the car.

Diagnosing.

First thing to do is put a vacuum gauge on it when its running. Any valve problems and that gauge needle will be jumping.

When you do a compression test make sure to have the throttle open so the air can get sucked in past the throttle plate.

Pull all the plugs and pressurize each cylinder on top dead center of the compression stroke with a rubber tipped blow gun. If the air comes out the intake you have an intake valve problem. If It comes out the exhaust you have a exhaust valve issue. If it comes out the oil breather you have bad rings or a hole in a piston. If it comes out the next door cylinder you have a blown head gasket. If it comes out the radiator you need go get a box of tissues to wipe away your tears.

Before bore scopes we use to also have what we called the "dipstick test" at work. If you pull the spark plug and can check the oil through the spark plug hole with your dipstick, it fails the "dipstick test". Your valve went through your piston. This was a real test. It saved us from wasting time pulling the engine apart. We then ordered a factory rebuild.

That roadster looks like a beautiful car. Too bad it has to just sit.... Mark

[Jack E/NJ]

Mice & nest in the hole! 8^) Jack E/NJ

[jan quaak]

y took of the manifold and it is oke now i remove the cylinder heads and look if everything is oke there

[Flathead Fever]

Originally Posted by jan quaak

y took of the manifold and it is oke now i remove the cylinder heads and look if everything is oke there

I would "not" have pulled the heads before you had found the problem. Its going to make it harder to diagnose. This is very unusual to have zero vacuum on one half of the intake manifold, unless that half of the manifold is plugged? Look at the side of the intake port that was not sucking and see which four cylinders it goes to. The problem has to be with one of those four cylinders. Did you check the valves for leakage before you pulled the heads off? Are all the valves going up and down when you rotate the crank? Stick a blow gun in the intake ports with a rag stuffed around it to make a seal and blow into the port and see if the valves are making a good seal.

The comment about the mouse nest is no joke. They can build a nest and plug up exhaust ports and an intake manifold if the carb is off. I just pressure washed a flathead block last week and one side's water jackets were completely packed full with a mouse's nest.

Year's ago I bought a '51 Merc motor. It wasn't running correctly so the guy ( the original owner) took it to a mechanic. The mechanic convinces him that the reason its not running good is because its an old "flathead". He convinces the customer to let him install a Chevy in it (thousands of dollars for the conversion). I buy the engine from the mechanic for $400.00. Figuring that if the block turned out to be junk I would at least end up with a Merc crank. The block had no cracks at all, standard bore and that 4-inch Merc crank. When I pulled the intake off there was the problem. I found one of the valve assembly retainers had come out of the valve guide (I'm not sure how that happened)? The whole valve assembly must have been just floating up and down.

A good mechanic with a vacuum gauge would have spotted the valve problem in just a few minutes of diagnosing. Hardly any mechanic uses vacuum gauges anymore?

While the engine was running, pulling one plug wire at a time and listening for the rpm drop of each of the good cylinders would have identified which cylinder was not firing (no rpm drop). A compression check on that cylinder would have probably been zero pounds. As soon as you pulled the intake, the problem would have been obvious, a retainer laying in the lifter valley. This could have been fixed for the price of an intake gasket.

[jan quaak]

Originally Posted by Flathead Fever

I would "not" have pulled the heads before you had found the problem. Its going to make it harder to diagnose. This is very unusual to have zero vacuum on one half of the intake manifold, unless that half of the manifold is plugged? Look at the side of the intake port that was not sucking and see which four cylinders it goes to. The problem has to be with one of those four cylinders. Did you check the valves for leakage before you pulled the heads off? Are all the valves going up and down when you rotate the crank? Stick a blow gun in the intake ports with a rag stuffed around it to make a seal and blow into the port and see if the valves are making a good seal.

The comment about the mouse nest is no joke. They can build a nest and plug up exhaust ports and an intake manifold if the carb is off. I just pressure washed a flathead block last week and one side's water jackets were completely packed full with a mouse's nest.

Year's ago I bought a '51 Merc motor. It wasn't running correctly so the guy ( the original owner) took it to a mechanic. The mechanic convinces him that the reason its not running good is because its an old "flathead". He convinces the customer to let him install a Chevy in it (thousands of dollars for the conversion). I buy the engine from the mechanic for $400.00. Figuring that if the block turned out to be junk I would at least end up with a Merc crank. The block had no cracks at all, standard bore and that 4-inch Merc crank. When I pulled the intake off there was the problem. I found one of the valve assembly retainers had come out of the valve guide (I'm not sure how that happened)? The whole valve assembly must have been just floating up and down.

A good mechanic with a vacuum gauge would have spotted the valve problem in just a few minutes of diagnosing. Hardly any mechanic uses vacuum gauges anymore?

While the engine was running, pulling one plug wire at a time and listening for the rpm drop of each of the good cylinders would have identified which cylinder was not firing (no rpm drop). A compression check on that cylinder would have probably been zero pounds. As soon as you pulled the intake, the problem would have been obvious, a retainer laying in the lifter valley. This could have been fixed for the price of an intake gasket.

thanks for the info i am going to do the test with the blow gun and the rag

i have checked al the valves the are al working so this story wil be continued