Engine stuck on 63 cub with new pistons and valves

[Paul 300 U]

A tenth of a turn is maybe 10 to 15 teeth on the ring gear. That is not enough to get close to a full stroke in a cylinder. Thus what ever it is is happening within a short piston travel, or cam shaft movement. tooth off of a cam gear, or distributor locked up from a long screw in the breaker plate or other "quick" thing stopping it. I would use an endoscope (cheap tool with a smart phone) to look around in the cylinders. I would also remove the distributor to see if that could be locking it up. I would search until i find the issue and for sure not force it through. Jim

Jim. Thanks. I'm going to start with the distributor. I never forced anything. I was concerned that everything might not be assembled correctly (apparently I was correct) so I firsttried to rotate it with the hand crank, I never used the starter, so I'm hoping there are no broken teeth.
I do have a phone scope. Are you recommending I remove the oil pan and head to get a look at the cylinders or try to fish through the plug openings. Feel free to add detail, you are well aware of my mechanical acumen! Paul

 

[Paul 300 U]

Maybe I missed it but this engine was never started? Or was it run?

Kshansen. This was a running tractor that I decided to replace pistons and valves. It smoked some and lacked power. No other real engine issues. Thanks Paul

 

[used red MN]

This was a running tractor that I decided to replace pistons and valves.

Oct. 24, 2034 thread on project
Dec 20 Cub engine thread
Basically I don’t think it had been started after the rejuvenation/overhaul. There are a few other threads on it as well.

 

[old]

Kshansen. This was a running tractor that I decided to replace pistons and valves. It smoked some and lacked power. No other real engine issues. Thanks Paul

When you replaced those parts did you prelube all the parts and also are you sure you got the rods back in the correct way. Not sure if you could put the rod in 180 out but I know in some engine you can and then when you try to turn it over the rod hits and locks the engine

 

[kshansen]

Kshansen. This was a running tractor that I decided to replace pistons and valves. It smoked some and lacked power. No other real engine issues. Thanks Paul

So then the only things done were to remove head and oil pan, remove pistons and connecting rods and valves then reassemble with new pistons and valves. After this engine was never started and then while trying to turn it over it was found to "lock up"?

 

[Paul 300 U]

Kshansen. This was a running tractor that I decided to replace pistons and valves. It smoked some and lacked power. No other real engine issues. Thanks Paul

Correct, never restarted. Thanks Paul

 

[Paul 300 U]

When you replaced those parts did you prelube all the parts and also are you sure you got the rods back in the correct way. Not sure if you could put the rod in 180 out but I know in some engine you can and then when you try to turn it over the rod hits and locks the engine

Old. I did prelube. I know a lot was made in several of the tutorials I watched about keeping the rods in their correct order and attaching the rod caps turned correctly to face the cam. I believe I paid attention to those points but it sure feels like something is hitting metal on metal. It's a dead stop not a soft stop. There is no "give" once contact is made. Again, I only used a hand crank and no force.
Thanks. Paul

 

[Fritz Maurer]

Possibly inadvertently left something in the cylinder when you installed the head?

 

[used red MN]

Possibly inadvertently left something in the cylinder when you installed the head?

I am wondering if this is a possibility. Or something dropped in a spark plug hole that you weren’t aware of. Even if they are way out of adjustment the valves can’t hit the pistons on flat head engine.

 

[used red MN]

Possibly inadvertently left something in the cylinder when you installed the head?

I am wondering if this is a possibility. Or something dropped in a spark plug hole that you weren’t aware of. Even if they are way out of adjustment the valves can’t hit the pistons on flat head engine. Maybe an endoscope is your best answer. If you have a smart phone you can get one relatively cheap. The one I am linking is only an example, I have no experience with that one. It just came up in a quick search. Example bore scope

 

[Jim Becker]

If it truly hits a hard stop BOTH WAYS within 1/10 of a revolution, anything lost on top of a piston would have to be huge, more than a couple inches long. It should be easily seen with a bore scope through a spark plug hole.

Likewise, most anything else would have trouble causing two hard stops within that little rotation.

 

[used red MN]

If it truly hits a hard stop BOTH WAYS within 1/10 of a revolution, anything lost on top of a piston would have to be huge, more than a couple inches long. It should be easily seen with a bore scope through a spark plug hole.

Likewise, most anything else would have trouble causing two hard stops within that little rotation.

Jim, I agree with all that. It’s easy to hop into the spot rustred goes to. Very difficult to diagnose long distance, if you were there hands on the time needed to get to the answer would be much shorter. If it is the stuck in gear thing as I mentioned there is also a possibility that the clutch plate is stuck to the flywheel and not releasing if he has tried turning it with the clutch down. You wouldn’t think that would be the case on a tractor that was running within the last year but never say never.

 

[old]

Old. I did prelube. I know a lot was made in several of the tutorials I watched about keeping the rods in their correct order and attaching the rod caps turned correctly to face the cam. I believe I paid attention to those points but it sure feels like something is hitting metal on metal. It's a dead stop not a soft stop. There is no "give" once contact is made. Again, I only used a hand crank and no force.
Thanks. Paul

Pull the oil pan back off if it has oil in it drain that first then move the crank till it locks and have a look see from the bottom to see what might be going on. Before you put the rings on the piston did you size them in the cylinder to make sure they had the correct end gap. Lack of end gap can cause it to lock up

 

[Paul 300 U]

I got back to the cub today to see if I could make progress on the leaking head gasket. I figured I would try to run it to see if it would self seal when it got hot.
I checked the oil pan with my scope camera to verify no antifreeze made it's way down there. It was dry so I added oil. I decided that it would be smart to turn the engine over a time or two with the hand crank just to make sure there were no big issues. Well, apparently there an issue some where because the crank moved about an inch then stopped like it hit metal. I gently tried to move it and gently rocked the tractor to see if it was a minor sticking issue. No luck. It's locked tight.
For the record. New pistons, valves, valve guides, keepers, rod bearings as well as filters and plugs. I used assemblers on the valves, bearings and a light coat if oil in the piston cylinder bores. As I was reassembling everything seemed to be moving fine. I didn't want to roll the over until I had it assembled.

As always I appreciate the help! Paul

Thanks to everyone for the suggestions, they helped me find a logical starting place. I began by removing the starter then moved on to the distributor no luck turning the engin. I decided to remove the head and after removing the necessary attached parts I began loosening the bolts and periodically testing the crank. When the bolts were all about half out I tested the crank and the head at piston 4 popped up. I finished removing the head and it appears that the dome on the new pistons is hitting the head. Hopefully it's another rookie mistake and I should have oriented the pistons so the dome is in the indented side of the head.
I'm not certain if I'm correct or if it's even possible to turn the pistons that way. Any thoughts and suggestions are as always appreciated. Pal

 

[old]

Thanks to everyone for the suggestions, they helped me find a logical starting place. I began by removing the starter then moved on to the distributor no luck turning the engin. I decided to remove the head and after removing the necessary attached parts I began loosening the bolts and periodically testing the crank. When the bolts were all about half out I tested the crank and the head at piston 4 popped up. I finished removing the head and it appears that the dome on the new pistons is hitting the head. Hopefully it's another rookie mistake and I should have oriented the pistons so the dome is in the indented side of the head.
I'm not certain if I'm correct or if it's even possible to turn the pistons that way. Any thoughts and suggestions are as always appreciated. Pal

I've almost never seen step pistons used in a flat head but it could be possible. You will need to pull each piston off the rod at the wrist pin to rotate the piston. I would then set the head on no nuts/bolts and spin the engine over to see if the head moves from being hit by the pistons

 

[Jim.ME]

Thanks to everyone for the suggestions, they helped me find a logical starting place. I began by removing the starter then moved on to the distributor no luck turning the engin. I decided to remove the head and after removing the necessary attached parts I began loosening the bolts and periodically testing the crank. When the bolts were all about half out I tested the crank and the head at piston 4 popped up. I finished removing the head and it appears that the dome on the new pistons is hitting the head. Hopefully it's another rookie mistake and I should have oriented the pistons so the dome is in the indented side of the head.
I'm not certain if I'm correct or if it's even possible to turn the pistons that way. Any thoughts and suggestions are as always appreciated. Pal

If I am seeing this correctly, this kind of looks like you put two in backwards, as the raised areas are towards the valves on two pistons (#1 & #2) and away from the valves on the other two (#3 & #4). These are the pistons that were in this engine, correct?

Did you have the pistons off the rods? If so, you might have a problem there, as well. Rods generally have a specific orientation as well as the pistons.

 

[used red MN]

If I am seeing this correctly, this kind of looks like you put two in backwards, as the raised areas are towards the valves on two pistons (#1 & #2) and away from the valves on the other two (#3 & #4). These are the pistons that were in this engine, correct?

Did you have the pistons off the rods? If so, you might have a problem there, as well. Rods generally have a specific orientation as well as the pistons.

What Jim said times two!

 

[old]

If I am seeing this correctly, this kind of looks like you put two in backwards, as the raised areas are towards the valves on two pistons (#1 & #2) and away from the valves on the other two (#3 & #4). These are the pistons that were in this engine, correct?

Did you have the pistons off the rods? If so, you might have a problem there, as well. Rods generally have a specific orientation as well as the pistons.

His original said he put in new pistons and valves so they would have been off the rods

 

[Jim.ME]

His original said he put in new pistons and valves so they would have been off the rods

My apologies to Paul 300 U, I missed the new pistons in your first post here in this thread or it didn't register, apparently. Still, used or new pistons, two of them appear to be in backwards and it is possible some are on the rods wrong. Rod orientation as well as piston orientation needs to be checked.

 

[rustred]

Rustred thanks for the reply. Now that you say it, I suppose you'd have to be correct. I would have had to turn over the engine to set the valves. It didn't occur to me as I was concentrating on following a pattern I read regarding which valves to adjust depending on where you start, then focusing on getting them gapped correctly. I've never done that before so it didn't occur to me that I would have had to turn the engine.
It's been sitting with the coolant in it for over a week. Hated to do that but out of town for the holidays. I also didn't know the water first, coolant second process until now. I will follow the process you described above once it's drained and refilled with water.
Finally, unfortunately the radiator plug is now stuck tight. Seems odd since I just had it off. Fortunately I haven't rounded the corners off yet. My next attempt will be to buy a torch and heat it. First time for that too! Thanks Paul

hate to inform u, but u have 2 pistons in backwards, very easy to see in the photo, see nothing like posting pictures, no guessing or making up all kinds of what if's.