Un-Seizing a Ford 302 5.0L

[Dale Moser]

No the pistons are more than likely stuck and the movement is just the slack in the chain

I assumed he was turning the crankshaft pulley.


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[mudkat]

and what did the plugs look like when you pulled them ? rusty ?oily ?

[scott123456789]

I assumed he was turning the crankshaft pulley.


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Yes I am. That’s why I was a bit confused by timing chain slack.

[Hoggslayer]

Let it soak. Put some more in it and let it soak. If that doesn't work let it soak some more. When you turn the crank, grad the outside of the pulley with a belt wench; so you don't break the crank bolt. I've seen many old truck free up and run like a top. That Marvel Mystery Oil is great stuff.

[scott123456789]

and what did the plugs look like when you pulled them ? rusty ?oily ?

One Cylinder has a rusty spark plug but it wasn’t terrible. Others seemed pretty normal for an older vehicle.

[mudkat]

that’s not good most likely the cylinder is rusted and the rings will be trashed https://m.autozone.com/loan-a-tools/...pection-camera
autozone loans out a borescope look in there and see what it looks like

[CabezaBlanca]

One Cylinder has a rusty spark plug but it wasn’t terrible. Others seemed pretty normal for an older vehicle.

Obviously from water in the cylinder. Good sign of a blown head gasket or cracked head.

[SCORPION KING]

Yes I am. That’s why I was a bit confused by timing chain slack.

The timing chain is connected to the crankshaft and camshaft sprocket

[Tryton]

You can get a cheap bore scope off amazon that connects to your phone. Take a look in the cylinders but most likely you will need to pull it and freshin it up.

[scott123456789]

I got a minute after work and was getting 1/4 turn on the crank bolt. Effort is minimal and then it hits a wall in both directions. I ran out of Marvel so I ran a tube on a can of PB blaster and tried to hit the valves in each cylinder.

Going to pull the valve covers off after dinner.

[Dale Moser]

The timing chain is connected to the crankshaft and camshaft sprocket

But if he’s turning the crankshaft bolt, the movement he feels is the pistons moving. If the pistons were seized the crankshaft would not turn at all and to feel timing chain slack he’d have to be turning on the camshaft side.


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[dgilbert]

Tear the motor completely down.

[cva34]

I've used a 50/50 mix of diesel fuel and ATF for soaking the pistons with great results.

Fill up whole engine crankcase tell it runs out Valve covers with That mix maybe lower atf some to keep cost down let it sit a week or so then with plugs out ,try

[scott123456789]

Well after pulling Valve Covers, while a few valve seemed stiffer than others, they all had no problem coming off the valve seat and returning. I went ahead and oiled them. No change in the movement in the crank but could watch a few valves cycle.

Thinking of giving the cylinders another week to soak and then pulling the heads.

[GarGuy]

Gonna be a stuck valve. The fellow that said the movement is the slack in timing chain may be right. Stuck valve.

You could pull valve covers and tap the intakes with a hammer. Might free it up.