VALVE STUCK

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Mar 31, 2024 | 04:56 PM

lalberts

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Tuned

Joined: Oct 2016

Posts: 255

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From: South dakota

VALVE STUCK

I have a 73 F-250 with a 390 FE and had a problem suddenly started running like crap and found I have a bent pushrod on #4 cylinder and the exhaust valve is stuck down. Why would it suddenly do this after running fine for 12000 miles since rebuild? I know the rebuilder installed hardened valve seats says so i can use unleaded gas. I have a hunch the valve seat dropped out, is that possible?

Mar 31, 2024 | 05:26 PM

440 sixpack

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Joined: Oct 2018

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Most likely it kissed a piston.

the why is hard to say. overrevved it and floated ? tight guide with insufficient oil? I've never seen a seat come out but I cant say it didn't. or sometimes crap happens.

Mar 31, 2024 | 08:42 PM

tbear853

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Joined: Feb 2004

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From: The Shenandoah Valley

Quote:

Originally Posted by 440 sixpack

I've never seen a seat come out but I cant say it didn't. or sometimes crap happens.

1980 Plymouth, 360, long pursuit, hot summer, car got hot, seats dropped out of two valves. Before I got the car another unit had it and a local dealership had done some head work on it.

Later I had it eat some cam lobes, then the next day after they "fixed" that, made it 20 miles from the dealership and a couple rods were knocking as I pulled up to our office gas pump. Got a whole engine brought up from HQ chained down on a roll back from out of a wreck. It run great from then on.