# Sudden stop



## Herman H (3 mo ago)

I have a 9N -It was sitting there ideling when it banged to a sudden stop-You can rotate the engine both ways but not all the way around --Any thoughts of what went wrong & the next step for repairing it? Thank you


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## Barry1950Ford8N (Feb 14, 2020)

Herman H said:


> I have a 9N -It was sitting there ideling when it banged to a sudden stop-You can rotate the engine both ways but not all the way around --Any thoughts of what went wrong & the next step for repairing it? Thank you


Could possibly be the fiber timing gear driven off the cam shaft. Happened to me once.


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## Groo (Jan 17, 2020)

Moving freely, but not able to do a complete revolution strikes me as probably something in a combustion chamber. As this is a flat-head engine, a dropped valve or messed up timing wouldn't do it. you could put a scope down the spark-plug holes to see fairly easily. If none availiable, I would probably pull the head and see what is up


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## Ultradog (Feb 27, 2005)

Groo said:


> Moving freely, but not able to do a complete revolution strikes me as probably something in a combustion chamber. As this is a flat-head engine, a dropped valve or messed up timing wouldn't do it. you could put a scope down the spark-plug holes to see fairly easily. If none availiable, I would probably pull the head and see what is up


As you stated yourself it is a flat head.
What would he accomplish by pulling the head?


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## FredM (Nov 18, 2015)

Herman -- you have one of 3 possibilities, behind the timing case, blown gears, -- blown con rod, -- or a valve head has come off of a valve stem and is sitting on top of the piston and jamming against the head.

Does the engine rotate 90°, 180°, or even nearly 360° before jamming?.

You can check for blown timing gears by removing the distributor cap and watch for rotation as you move the crankshaft.

If you remove the head, you will see if a valve has parted and if you rotate the engine, you will see if a con rod is broken by a piston not moving.

Simple engine, simple checks.


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## Groo (Jan 17, 2020)

Ultradog said:


> As you stated yourself it is a flat head.
> What would he accomplish by pulling the head?


I said, it sounded like something was in the combustion chamber. As it is a flat-head, it is pretty simple to pull the head and see exactly what the condition of the combustion chamber and see exactly what the piston and valves are doing. I also suggested first getting a look through the spark plug hole if you can.


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## RandR10 (Sep 2, 2016)

Sounds like it may have thrown a rod. They often won't open a window in the block when this happens at lower engine speeds. Broken rod will then lodge somewhere and interfere with engine rotation when the crank throw comes around and hits it. Pull the pan and take a look. If you can get ahold of a bore scope you could simply drain the oil and peek in through the drain hole to see if one of the rods checked out.


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## Groo (Jan 17, 2020)

RandR10 said:


> Sounds like it may have thrown a rod. They often won't open a window in the block when this happens at lower engine speeds. Broken rod will then lodge somewhere and interfere with engine rotation when the crank throw comes around and hits it. Pull the pan and take a look. If you can get ahold of a bore scope you could simply drain the oil and peek in through the drain hole to see if one of the rods checked out.


pulling the head or looking through the spark plug hole, would also give you that information with less work and mess.


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## Joe.S.AK (Nov 26, 2020)

All the info you gather will help. It could be an errant snapped or escaped valve in the cylinder or possibly a broken connecting rod in the lower areas - all of the bits you gather will rule things out or be a possible cause.

For example after exhaustively looking for snapped, broken or jammed parts in the head area I would then slowly progress to tearing into the belly of the beast and just pull the oil pan. That way you can check all 4 cylinders top and bottom. Something like sneaking a look into the oil drain plug might well start you off just before checking out 'down below'.

First things first - I would go for the easy things first and then progress from there to more comprehensive checking. (Yeah - we all know that concept until our very own Ford built heart throb / sweetheart suddenly just quits).

Let us know what you have started checking off the list. Pulling plugs and inspecting upper 'stuff' like the rocker arm / valves area seems to be a good start in this case since it does sound like something has lodged in a cylinder under the head. If nothing there then, alternately, something lower down in the block.
- Joe


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## xxxjd950xxx (May 11, 2017)

Joe.S.AK said:


> All the info you gather will help. It could be an errant snapped or escaped valve in the cylinder or possibly a broken connecting rod in the lower areas - all of the bits you gather will rule things out or be a possible cause.
> 
> For example after exhaustively looking for snapped, broken or jammed parts in the head area I would then slowly progress to tearing into the belly of the beast and just pull the head. That way you can check all 4 cylinders and the head area.. Something like sneaking a look into the oil drain plug might well start you off afterwards in checking out 'down below'.
> 
> ...


Pull all the plugs and make sure all pistons are moving when you turn the crank.


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## Joe.S.AK (Nov 26, 2020)

OK - no matter what, you're going to need to* look into each cylinder at least from the top* to check all 8 valves as well as seeing the pistons are all moving as they should. For all we know a spark plug could have 'grenaded' and dropped stuff into the cylinder, a valve broke and parts are lodged somewhere, a sleeve slipped out of place somehow or any of at least a half dozen other things. 

Right now "She's-a no-go-anywhere" and so for a little time, effort and the price of head and manifold gaskets you will either:

1 - Find the bent, broken or who-knows-what problem (including pistons not going up and down) from inspecting the top of the engine first. 

2 - If there is a piston which won't move it will be very obvious and then whats broken is certainly in the bottom end - and then THAT will also need to be opened up. 

There is no saving of time, effort or troubleshooting diligence by going to all the effort of pulling the fuel tank/hood and plugs just trying to squint into four little spark plug holes. The fact of the matter is that you're going to have to tear into it anyway - so just do it. 

Were it I (and yes, it certainly is not) I would pull the head to inspect the top of the engine first and if everything is squeaky clean and OK then just go further from there.

- Joe -


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