crank rotations/one turn of timing chains
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5th Gear
Joined: Dec 2025
Posts: 5
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From: Tennessee
crank rotations/one turn of timing chains
Working on a 5.4 2C ford engine with a problem. Engine has been rebuilt recently but has come down with a total engine lockup. Manual turning the crank several rotations seems good but a few more turns it locks up. Turn it slightly backwards and it frees up. The question I have is how many turns of the crank is required to rotate the timing chains one full turn. I have a feeling it is a timing chain issue. Thoughts please.
Last edited by Unicoiman; Feb 27, 2026 at 06:24 PM. Reason: Correct spelling
Thread Starter
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5th Gear
Joined: Dec 2025
Posts: 5
Likes: 1
From: Tennessee
Thanks for the reply but that is not what I am asking. My question is how many rotations of the crank is required to rotate a timing chain one full rotation. Example, say you mark the timing chain at the crank and then rotate the crank until the timing chain makes one full rotation back to where it started. Before pulling the engine I am trying to look at all possible causes for the lockup. Is it possible the lockup is occurring when one of the timing chains gets to a particular position. Should that be the case that would explain why the crank will turn several turns before locking up. I am open to ideas.
Thread Starter
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5th Gear
Joined: Dec 2025
Posts: 5
Likes: 1
From: Tennessee
Awar,
Many thanks because you saved me much time in locating a chain and sprocket. Now a little update. After reading a lot of articles on locked up engine suggestions were to remove the starter and serpentine belt. With both removed the engine was still locked up. Turned crank about 10 degrees counterclockwise and then clockwise and engine freed up. Proceeded to turn crank manually 14 turns without issues. Either something in the timing area or cams has come loose or broken causing an intermittent lockup. Next plan is to remove the valve covers and timing cover and look for issues. This is the first engine that I've ever had an issue with like this and can't wait to tear into it. Will update when problem is found.
Again, thanks for the information.
Many thanks because you saved me much time in locating a chain and sprocket. Now a little update. After reading a lot of articles on locked up engine suggestions were to remove the starter and serpentine belt. With both removed the engine was still locked up. Turned crank about 10 degrees counterclockwise and then clockwise and engine freed up. Proceeded to turn crank manually 14 turns without issues. Either something in the timing area or cams has come loose or broken causing an intermittent lockup. Next plan is to remove the valve covers and timing cover and look for issues. This is the first engine that I've ever had an issue with like this and can't wait to tear into it. Will update when problem is found.
Again, thanks for the information.
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