34 Flathead only turns about 45 degrees then catches

[Robbo]

I have a 34 Ford Phaeton that I am working to restore. When I turn the crank, it will only turn about 45 degrees then stops with what sounds like a thud in the front left of the engine. The wiring is completely out of the car now, so no use of the starter. Heads are off as I am cleaning all the accumulated gunk out. Cylinders and pistons look good and move freely for the little bit that the engine will turn. Any ideas what might be holding it back?

[Lanny]

Could be a stuck valve. Use a real good penetrating spray and
spray the valve stems, guides and lifters real good.



.

[alanwoodieman]

connecting rod--what type engine is it-original? 59ab?8ba?

[aussie merc]

I would lift the intake and have a look but wouldn't be surprised if its a stuck valve . Nothing beats having a look intakes aren't major surgery and its good to check valve clearance anyway .As for using the starter on a stuck engine NEVER; if it wont turn by hand there's something wrong and that starter just might be the pin in the hand grenade

[David J]

did not read all and my comments were useless. sorry

[Terry,OH]

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Yes as mentioned above do not use the starter unless you can rotate the crank 720 degrees or more by hand. Beside a badly stuck valve the timing gears could be messed up or even the oil pump. I also think removing the intake manifold is the next step. also a broken piston ring could be the problem.

[chap52]

oops

[marko39]

I vote for a stuck valve. See if engine will turn backwards and stops indicating a valve stuck partially open.

[Eodcoduto]

Could be a bent rod hitting the bottom of the piston. I just rebuilt a 366 Chevy with that issue.

[tubman]

"If you hear hoofbeats, think horses, not zebras."

[Flathead Fever]

Originally Posted by Terry,OH

Yes as mentioned above do not use the starter unless you can rotate the crank 720 degrees or more by hand. Beside a badly stuck valve the timing gears could be messed up or even the oil pump. I also think removing the intake manifold is the next step. also a broken piston ring could be the problem.

I agree with the no starter. I had small gear reduction starter bend a rod on a Ford V10 with a blown head gasket at work. The vehicle was running when I parked it. While it sat the cylinder filled with coolant and when I cranked the engine it bent the rod, not just a little but a whole lot of bend. That rod is hanging out in my garage to remind me to stop and think.

It could have a stuck but if it sat for a long time and a gasket leaked coolant into the cylinder and then somebody tried to crank it, it could have bent a rod. Before you crank an unknown engine rotate it two turns by hand first before you try the starter.

Rotate the crank in the opposite direction. It rotates twice for every time the camshaft rotates once. Since you have the heads off you should be able to see all the valves move except for a stuck one. Like others said, you might as well pull the intake since it's an easy job.

[Robbo]

Thanks everyone

Stuck Valve(s) was the issue... Marvel mystery Oil and a tiny shot of PB Blaster in each valve was the solution. (along with a little patience)

[Mart]

Thanks for feeding back. Often we are left wondering. Glad you got it freed up.

[Bored&Stroked]

Good news! Much appreciate you coming back on the Barn - it helps when folks see that "solutions" worked. Best of luck!

[Bored&Stroked]

BTW, post some pics of your project - we're always interested in looking at what others are working on.