camshaft JD B

[nutsoverJD]

Fixingfarmer asked about the silicone on the crankshaft end. That looks like JB Weld.

Given the fact that you are convinced the cam is messed up and/or wrong, I’d stop trying to start the engine and start disassembly of the reciprocating assembly. If the splines under that mess on the flywheel are damaged, you’ll need the crank replaced too. To get the cam out, you’ll need to strip down everything in the crankcase anyway.

Did you compare the length of the pushrods to make sure they’re equal? Faulty cam follower (not sure how that’s possible though)?

Did the prior owner give any detail what was done before you bought it?

No history of the tractor. You are correct it is JB weld. Push rods are equal length. Can't explain why LH valves are correct RH aren't. Sounds like I have a JD B for parts.

 

[Mark-Ia]

You need that tin nut on the end of the crankshaft to set the endplay on the crankshaft to allow the clutch to operate correctly. Might be time to cut your loss and get something else.

 

[Loosehandle]

No history of the tractor. You are correct it is JB weld. Push rods are equal length. Can't explain why LH valves are correct RH aren't. Sounds like I have a JD B for parts.

Just get a tractor in better condition that runs.

 

[Fixingfarmer]

No history of the tractor. You are correct it is JB weld. Push rods are equal length. Can't explain why LH valves are correct RH aren't. Sounds like I have a JD B for parts.

they won’t be consistent on both sides. Rotate crank 360 if you are trying for tdc on the right and you are at the right and have valves opening

180 degree crank offset

4 stroke so the valves aren’t quite done with their business yet you likely won’t have tdc except maybe left side with all 4 valves perfectly closed.

It’s what makes the Johnny popper noise there’s a skip

You have enough other things going on with this I’d agree with your parts tractor thought the late b is worth more of a struggle than earlier ones but crank and flywheel will cost more than it’s worth.

 

[buickanddeere]

yes i checked the manifold. did you see my post and pictures of the rocker position at compression TDC on both cyl. RH has the intake open on the waste spark the LH doesn't. that says something wrong with the cam.

Plug wires swapped ?

 

[Mike(NEOhio)]

In my PM this morning I mentioned setting the valve clearances but I want to clarify a bit more. First back off all four rocker arm screws, a lot. Then with the plugs out and thumb over the hole on the left, holding the two LH pushrods in, toward the rear, roll the flywheel to TDC a few times. You will feel compression on every stroke but the pushrods will NOT move on one of them. That is your compression stroke and the place to set the rocker arm clearance for the left side. Then roll it 180 and set the right side rockers. I find this helpful bc even on the exhaust stroke it will push some air through the plug hole that feels like compression.

 

[used red MN]

Also I am reasonably certain that one valve would be open at one of the tdcs either one or 2 that’s normal the other tdc they will both be closed or close enough to it to appear so. If there were 4 or 6 cylinders you would have to rotate 360 degrees to the other tdc to do the other half of the valves so on one of the TDCs it should be different than the other. If you put the flywheel a quarter turn before LHEO on the compression stroke you can adjust all the valves.

This is exactly what I was going to put in my reply 38 but felt like he had me convinced about his cam. Because of the fire 1, then fire 2, then the pause to get back to fire 1 the valves are going to position different in following parts of the 4 cycle rotations. Never thought about the way they fire as being a 4 cylinder cut in half and the other cylinders that would normally fire in two rotations of the crank aren’t there. The JD 2 cyl. fires 1 then 3 but 4 and 2 are not there, is that essentially correct?
Edit: I said cut in half but that isn’t exactly true either because I say it fires 3. The Deere cam lobes for the right cylinder are positioned as they would be for cylinder 3 (of the 4 cyl.) in the cut-off scenario.

 

[nutsoverJD]

Plug wires swapped ?

The mag fires on both cylinders (compression and waste spark on other cyl).

 

[nutsoverJD]

In my PM this morning I mentioned setting the valve clearances but I want to clarify a bit more. First back off all four rocker arm screws, a lot. Then with the plugs out and thumb over the hole on the left, holding the two LH pushrods in, toward the rear, roll the flywheel to TDC a few times. You will feel compression on every stroke but the pushrods will NOT move on one of them. That is your compression stroke and the place to set the rocker arm clearance for the left side. Then roll it 180 and set the right side rockers. I find this helpful bc even on the exhaust stroke it will push some air through the plug hole that feels like compression.

I roll the push rods to be sure valves are fully closed

 

[used red MN]

I roll the push rods to be sure valves are fully closed

I shouldn’t get in the middle of your conversation but.. depending on lash adjustments rolling the push rod will tell you the valve is closed. It doesn’t tell you how much the lifter has been pushed up/in by the cam. In other words If not obvious it can’t tell you the lifter is on the “base circle” of the cam, the part of the lobe that is not the lift bump.

 

[nutsoverJD]

I shouldn’t get in the middle of your conversation but.. depending on lash adjustments rolling the push rod will tell you the valve is closed. It doesn’t tell you how much the lifter has been pushed up/in by the cam. In other words If not obvious it can’t tell you the lifter is on the “base circle” of the cam, the part of the lobe that is not the lift bump.

I understand that but closed no pressure on the valve spring should be sufficient. I did check valve clearance at TDC for both cyl.

 

[used red MN]

The mag fires on both cylinders (compression and waste spark on other cyl).

So tell me this. Does a points distributor for one of those also fire the waste spark? I would guess not. If as you say the waste spark is causing the back fire into the intake I wonder if it would run with a points distributor? I am still not 100 percent convinced the cam is the issue.

 

[buickanddeere]

The mag fires on both cylinders (compression and waste spark on other cyl).

Still makes a difference as one plug is fired at a time .

 

[buickanddeere]

So tell me this. Does a points distributor for one of those also fire the waste spark? I would guess not. If as you say the waste spark is causing the back fire into the intake I wonder if it would run with a points distributor? I am still not 100 percent convinced the cam is the issue.

The mag or distributer on a numbered and first lettered series rotates at crankshaft rpm.

 

[buickanddeere]

So tell me this. Does a points distributor for one of those also fire the waste spark? I would guess not. If as you say the waste spark is causing the back fire into the intake I wonder if it would run with a points distributor? I am still not 100 percent convinced the cam is the issue.

The wasted sparks are supposed to occur just prior to TDC on the exhaust strokes.

 

[used red MN]

The wasted sparks are supposed to occur just prior to TDC on the exhaust strokes.

Okay, thanks on both of those replies!

 

[Fixingfarmer]

This is exactly what I was going to put in my reply 38 but felt like he had me convinced about his cam. Because of the fire 1, then fire 2, then the pause to get back to fire 1 the valves are going to position different in following parts of the 4 cycle rotations. Never thought about the way they fire as being a 4 cylinder cut in half and the other cylinders that would normally fire in two rotations of the crank aren’t there. The JD 2 cyl. fires 1 then 3 but 4 and 2 are not there, is that essentially correct?
Edit: I said cut in half but that isn’t exactly true either because I say it fires 3. The Deere cam lobes for the right cylinder are positioned as they would be for cylinder 3 (of the 4 cyl.) in the cut-off scenario.

Yes that is exactly correct so one way anyone who sets a lot of 4 and 6 cylinder valves could do it is tdc # 1 then rotate to 2 completely and do #2 just to make sure they are in the right spot. You can do them at tdc 1 and 2 you just stop there and don’t continue on to the opposite cylinder

It’s kind of a pain that they do have a spot to adjust them where the whole valve train is loose because it opens up the opportunity for a whoopsie if that spot isn’t actually found.

And it’s my opinion the cam is the shaft that’s fine. It’s likely the thing will start once whatever fuel or manifold issue is fixed. But the fact that crank is obviously not safe means he would be better off finding something else.

 

[ChrisInPA]

In one of these threads, nutsoverJD said he cleaned the carburetor. I'm curious what that entailed?

 

[nutsoverJD]

I have given up on this tractor. Thank you all for your help.