cylinders don't move when using hand crank to time engine on 49 cub.

[JimWV]

Cub just quit running other day. Replace pinion gear in distributor as rotor was sloppy. When trying to time engine to no.1 cylinder everything moves but the cylinders ???

 

[DaveBN]

Are you saying the pistons aren't going up and down? How are you turning the engine over, starter motor or hand crank?
Dave

 

[Mad Farmer]

Try turning it with the fan. Plugs out will be easier, good time to clean re-gap them......

 

[JimWV]

Are you saying the pistons aren't going up and down? How are you turning the engine over, starter motor or hand crank?
Dave

Hand crank piston dont move

 

[Janicholson]

Hand crank piston dont move

Welcome to YT Forums. We can get this going with more info. Did it stop like it was shut off, or like it was locking up? If there was no MAJOR noise it is difficult to believe the rod on #1 has come off. Remove all sparkplugs, Pit a plastic straw down each cylinder then crank it with the hand crank and report back. Jim

 

[rustred]

Cub just quit running other day. Replace pinion gear in distributor as rotor was sloppy. When trying to time engine to no.1 cylinder everything moves but the cylinders ???

Cub just quit running other day. Replace pinion gear in distributor as rotor was sloppy. When trying to time engine to no.1 cylinder everything moves but the cylinders ???

Cub just quit running other day. Replace pinion gear in distributor as rotor was sloppy. When trying to time engine to no.1 cylinder everything moves but the cylinders ???

on the larger models the crank thingy has a roll pin going through the crankshaft. if that roll pin breaks you will not be turning the crankshaft. just saying .

 

[JimWV]

It was sitting and idling nicely and just quit running. Would not restart and acted like an ignition issue.. Removed distributor cap and rotor would move about 1/4 inch in either direction. removed cover and pinion gear was in bad shape. Order new pinion and rotor. Installed new ones and pulled #1 plug to time using finger on hole to tell when #1 was on top. Inserted crank and you could hear the magneto trip and see the fan etc move but the cylinders won't.

 

[rustred]

put some paper towel plugs in in each plug hole and crank it. it should pop the plugs out .

 

[Tramway Guy]

Broken crank just behind the gear? That means the pulley would turn as well as the timing gears, but not the rest of the crankshaft.

 

[used red MN]

Hello Jim welcome to YT! My guess is unfortunately something has happened to the cam drive, gear came loose, key sheared or gear teeth stripped. Look in the spark plug holes you should see the valves. If they don’t move when you turn the engine what I have described above has taken place. Likely one of the cylinder will have some push/pull of air because its valves will be closed. The other cylinders will have no compression due to where the cam is stopped one or the other valve will be held open. To others on a Cub the distributor is on the opposite side of the engine from the cam so it has its own drive and can still turn independent of the cam.

 

[JimWV]

Thanks to everyone. I think used red mn got it. It seems the best answer at the time. Will update as I go
Thank you all again

 

[sotxbill]

put some paper towel plugs in in each plug hole and crank it. it should pop the plugs out .

It should also SUCK the paper in....to the cyls....

 

[sotxbill]

Hello Jim welcome to YT! My guess is unfortunately something has happened to the cam drive, gear came loose, key sheared or gear teeth stripped. Look in the spark plug holes you should see the valves. If they don’t move when you turn the engine what I have described above has taken place. Likely one of the cylinder will have some push/pull of air because its valves will be closed. The other cylinders will have no compression due to where the cam is stopped one or the other valve will be held open. To others on a Cub the distributor is on the opposite side of the engine from the cam so it has its own drive and can still turn independent of the cam.

Pistons would still go up and down though... However the cyls are not suppose to move. the pistons and valves... yes.

 

[used red MN]

Pistons would still go up and down though... However the cyls are not suppose to move. the pistons and valves... yes.

I didn’t come right out and say this as I was trying to be nice. My guess is the OP either felt or saw the valves not moving. He then incorrectly identified them as “cylinders” which by all purposes was meant as pistons.

 

[wore out]

Thanks to everyone. I think used red mn got it. It seems the best answer at the time. Will update as I go
Thank you all again

HOW are you determining that the "cylinders" or pistons are not moving?

Your Cub has a "flathead" engine and the sparkplugs are to the side, NOT over the pistons, and between the valves, making it difficult to see anything "moving" IF you are looking into the spark plug holes while cranking it.

 

[used red MN]

HOW are you determining that the "cylinders" or pistons are not moving?

Your Cub has a "flathead" engine and the sparkplugs are to the side, NOT over the pistons, and between the valves, making it difficult to see anything "moving" IF you are looking into the spark plug holes while cranking it.

WO, you liked my Taz post for rr in the gasket thread. You should read my replies in this post as well. Although, the OP has not said yes this is what happened, I think what I replied to Sox in #14 is what happened and will answer your query.

 

[Aaron SEIA]

If it's a flat head with the plug holes centered on top like the picture shows, use a screwdriver or long piece of wire down the hole while turning. If the wire goes up and down, then you know the pistons are in fact moving.
AaronSEIA

 

[grandpa Love]

Folks, with a Cub hood off, spark plugs out, and using a flashlight you can in fact see the pistons and valves moving ...... Why complicate the issue??...... Sometimes I know the answer but after reading everything on here I get confused

 

[used red MN]

Folks, with a Cub hood off, spark plugs out, and using a flashlight you can in fact see the pistons and valves moving ...... Why complicate the issue??...... Sometimes I know the answer but after reading everything on here I get confused

Nothing complicated or confusing about it if you read my replies. Also, by my thinking by what the OP said in reply 11 he is agreeing he misnamed some parts.

 

[Janicholson]

Nothing complicated or confusing about it if you read my replies. Also, by my thinking by what the OP said in reply 11 he is agreeing he misnamed some parts.

If the engine was on the compression or the following power stroke, the valves would not move, so the observation of not moving is easily explained. I think it will run with some external fixing. Jim