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Old 04-22-2018, 03:39 PM
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trevorhp
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Default Jammed engine

Hi Folks
Just bought a project car with a 'jammed' engine
It moves freely just a 1/4 turn using the crank bolt and then stops.
There is oil in the sump, water in the system and evidence of compression on turning.
Before I remove the motor and strip does anyone have any idea what it is likely to be.
The 1/4 turn is I believe the clue,
I have no other information
Thanks in anticipation.
Trevor
Old 04-22-2018, 05:06 PM
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dporto
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Originally Posted by trevorhp
Hi Folks
Just bought a project car with a 'jammed' engine
It moves freely just a 1/4 turn using the crank bolt and then stops.
There is oil in the sump, water in the system and evidence of compression on turning.
Before I remove the motor and strip does anyone have any idea what it is likely to be.
The 1/4 turn is I believe the clue,
I have no other information
Thanks in anticipation.
Trevor
have you tried removing the spark plugs?
Old 04-22-2018, 05:11 PM
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trevorhp
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Hi Not yet ................but I will tomorrow
Thanks for the suggestion
Old 04-22-2018, 05:18 PM
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Noz1974
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You should be able to turn it over even with compression, if it stops dead and feels mechanically solid, the piston is hitting a valve , could be a snapped cam chain, be careful not to force anything and cause extra damage ok
Old 04-22-2018, 05:32 PM
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Mike Murphy
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Most likely a broken rod. If a piston was hitting a valve, you might get more than 1/4-turn, although it’s possible that all pistons could hit valves in each cylinder if the timing is off.

If there was a single broken spark plug in a single cylinder, you’d be able to move more than 1/4-turn.

An unlikely cause: a faulty transmission. Try pushing the clutch all the way in by wedging something that pins the clutch all the way in and try again. It’s highly unlikely this is the problem, but technically possible. Yes, the transmission turns the gears even when in neutral.

I would remove the serpentine belt to make sure it’s not some weird thing with the belt or pulleys or a jammed and stuck-on AC pump.
Old 04-22-2018, 05:52 PM
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trevorhp
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Hi Thanks for the insight
It stops solid and I have not forced it for this very reason.
Old 04-22-2018, 05:53 PM
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trevorhp
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Hi
Thanks for the suggestions
I will try all of them and report back
Old 04-23-2018, 01:37 AM
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dan_189
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Long shot but maybe a jammed starter, although unlikely

Whats the history behind it?
Old 04-23-2018, 06:26 PM
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trevorhp
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Hi
I don't have any history at all bought cold from a third party
Old 04-23-2018, 06:29 PM
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dan_189
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Originally Posted by trevorhp
Hi
I don't have any history at all bought cold from a third party
History could also be things the seller may have mentioned. Like it was driving along and saw smoke or heard a rattle then stopped etc. Etc.
Old 04-24-2018, 08:31 AM
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Southern Man
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Hydrolocked?
Old 04-24-2018, 11:59 AM
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wildbilly32
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Pull the plugs as mentioned above. Then drop the oil pan. That will probably give you a good idea of the issue.
Old 04-24-2018, 04:18 PM
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fpb111
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Remove the accessory drive belt and make sure all pulleys turn. Couple years ago someone brought a failed engine to Flat Six and one of the idlers was seized. It stopped the engine from turning.
Old 04-24-2018, 04:25 PM
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fpb111
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Not uncommon for seized pulley to cause no turn condition.

https://grassrootsmotorsports.com/fo.../126145/page1/
Old 04-24-2018, 06:02 PM
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trevorhp
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Hi Guys
Thanks for all the suggestions still working on them in turn

I have no other background on this car
I bought it from a guy who bought it from an auction the previous owner was significantly absent
So I do not know the lead up to the demise of the engine sadly
The rest of the car has been neglected but is remarkably sound
All the pulleys turn even just the 1/4 turn is enough to see that although there may still be an issue further round the turn so I will remove the belts next
I will post all results as they happen
Trevor


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