John Deere 40 help needed

[FarrviewSouth]

I have got to be making a simple mistake but I cannot get a friends just rebuilt (not by me) but never started 40 to run. It gives every impression that the timing is not right

I have stripped it back down and confirmed the timing gear is matched correctly to the crank.

However, the IT manual says to align the number cylinder (front of engine) to the DC mark on the flywheel and insert the oil pump with the slot in the top gear with the small side toward the outside of the engine (which should be parallel to the block) . Then, in the ignition section, it says to align the number one piston to the spark mark and the slot again should be parallel. You can't have it both ways.......can anyone confirm which instruction is correct?

Also, the IT manual says, number one is the front, YT search engine says number one is toward the flywheel, again any confirmation?

Finally, (perhaps :>) can anyone confirm on the distributor approximately what position number one cylinder plug is (4 o'clock or 10 o'clock?)

Thanks for any input

Bruce

 

[Powered By IH]

When you said:

However, the IT manual says to align the number cylinder (front of engine) to the DC mark on the flywheel and insert the oil pump with the slot in the top gear with the small side toward the outside of the engine (which should be parallel to the block) . Then, in the ignition section, it says to align the number one piston to the spark mark and the slot again should be parallel. You can't have it both ways.......can anyone confirm which instruction is correct?

Did you pull the #1 spark plug and make sure that cylinder #1 was on compression both times?
#1 should be the front cylinder.

Sorry, I'm an IH guy on the JD forum right now, don't start any riots...

 

[Jim.ME]

#1 cylinder is at the front.

Number 1 cylinder must be at TDC, with both valves closed (on compression). The oil pump drive gear slot should be parallel to the engine at this point with the narrow side of the gear away from the engine. The DC mark should also line up at this point. Note the DC mark lines up when the exhaust valve is open which would put it 180 degrees out of time, be sure both valves are closed and have clearance.

The distributor drive tang when meshed into the slot in the oil pump gear will point the rotor button to locate where #1 in the cap needs to be (pictures in the manual put it roughly between 2 and 4 o-clock). You rotate the distributor body to adjust timing as needed from there.

Reality is that slot and drive tang can be anywhere and the engine can be properly timed to run. Following the procedure located the rotor to #1 cylinder in the distributor in the same location the factory had it

The YT search engine might be getting confused with the JD420 lawn tractor engine. You have to watch out for that as search engines and AI will grab anything John Deere 420.

 

[Fixingfarmer]

Jim.ME has much more experience I believe based on previous posts with the little ones but the rest of the 2 cylinders one thing I’ll do walking into something like this on a B like this summer where an attempt to pull the crank had occurred is to flip the wires around swap 1 and 2 since the distributor has a wasted spark every revolution both fire you can be 180 off and check it just by swapping the wires don’t be afraid to try that

This advice came from dealing with mags that only fit one way with the slots

As long as you have the crank timed you will get there

If you have a timing light and a good mark I usually put a silver sharpie on the mark and since it sounds like you have some help to crank you can get it lined up on the flash

 

[Jim.ME]

Jim.ME has much more experience I believe based on previous posts with the little ones but the rest of the 2 cylinders one thing I’ll do walking into something like this on a B like this summer where an attempt to pull the crank had occurred is to flip the wires around swap 1 and 2 since the distributor has a wasted spark every revolution both fire you can be 180 off and check it just by swapping the wires don’t be afraid to try that

This advice came from dealing with mags that only fit one way with the slots

As long as you have the crank timed you will get there

If you have a timing light and a good mark I usually put a silver sharpie on the mark and since it sounds like you have some help to crank you can get it lined up on the flash

As i said "Reality is that slot and drive tang can be anywhere and the engine can be properly timed to run. Following the procedure located the rotor to #1 cylinder in the distributor in the same location the factory had it."

Like most engines if #1 is at TDC compression, you can make it work using common practices.

 

[Gene Davis(Ga.)]

The oil pump has to be timed for the distributor to be timed right on those Dubuque engines. It takes a special tool as the drive tangs are offset on both items.

 

[Jim.ME]

The oil pump has to be timed for the distributor to be timed right on those Dubuque engines. It takes a special tool as the drive tangs are offset on both items.

I agree and recommend timing the oil pump gear per the manual, but it is not a case of it will not run ever, if it is not timed that way. A large screwdriver or piece of flat stock that fits the slot can be used to guide the gear mesh into the camshaft gear, in place of the JD special tool.

The biggest thing timing it by the book to locate the oil pump drive gear slot does is it makes so that the rotor lands in the same place the factory placed it. It can be put in anywhere and the engine timed by bringing #1 up on compression and setting the distributor body so that the cap terminal lines up with the rotor, same as you would set static timing on most engines.

 

[MikeinKy]

I have got to be making a simple mistake but I cannot get a friends just rebuilt (not by me) but never started 40 to run. It gives every impression that the timing is not right

I have stripped it back down and confirmed the timing gear is matched correctly to the crank.

However, the IT manual says to align the number cylinder (front of engine) to the DC mark on the flywheel and insert the oil pump with the slot in the top gear with the small side toward the outside of the engine (which should be parallel to the block) . Then, in the ignition section, it says to align the number one piston to the spark mark and the slot again should be parallel. You can't have it both ways.......can anyone confirm which instruction is correct?

Also, the IT manual says, number one is the front, YT search engine says number one is toward the flywheel, again any confirmation?

Finally, (perhaps :>) can anyone confirm on the distributor approximately what position number one cylinder plug is (4 o'clock or 10 o'clock?)

Thanks for any input

Bruce

I have rebuilt a bunch of them. The slot on the oil pump goes one tooth counter clockwise. to being lined up with the block. with the narrow side out. I bought a 420 engine cheap because they rebuilt it and coulbn't get it to run. I brought it home and pulled the distributer and it was one tooth out of time The distributer won't go in but one position if the oil pump is correct, you just drop the distributer in and turn it until it drops all the way.

 

[deeretails]

#1 is the front cylinder

 

[Jim.ME]

I have got to be making a simple mistake but I cannot get a friends just rebuilt (not by me) but never started 40 to run. It gives every impression that the timing is not right

I have stripped it back down and confirmed the timing gear is matched correctly to the crank.

However, the IT manual says to align the number cylinder (front of engine) to the DC mark on the flywheel and insert the oil pump with the slot in the top gear with the small side toward the outside of the engine (which should be parallel to the block) . Then, in the ignition section, it says to align the number one piston to the spark mark and the slot again should be parallel. You can't have it both ways.......can anyone confirm which instruction is correct?

Also, the IT manual says, number one is the front, YT search engine says number one is toward the flywheel, again any confirmation?

Finally, (perhaps :>) can anyone confirm on the distributor approximately what position number one cylinder plug is (4 o'clock or 10 o'clock?)

Thanks for any input

Bruce

Forget the back and forth about being able to make it run if the oil pump gear is not timed. It sounds like you have a manual and have checked that the gear is timed. How did you confirm that both valves on #1 cylinder were closed at that point?

The important thing is that 1 cylinder must be on TDC compression with both valves closed (clearance between the rockers and valve stems. The DC mark on the flywheel lines up when #1 is on the rock at the end of the exhaust stroke when the exhaust valve is just closing and the intake valve is just opening. If the oil pump was installed and timed at DC here it is 180 degrees out of time. and will place the distributor out of time.

If you confirmed the oil pump slot is such that the slot is parallel to the block with the narrow side of the gear to the outside (away from the block), with the valves closed and DC mark lined up, align the offset distributor drive tang with the oil pump gear slot and slide it down in. The rotor will point to where you want #1 wire to be placed in the cap, and it should start if all is correct.

 

[FarrviewSouth]

Thanks all for the replies and help. Snow removal is getting in the way of working on it today but I have already done the above and I will got back and check it again.....However, after looking a this sites parts section, it appears that the original owner purchased the cap for a 12 volt instead of a 6 volt one. I did not realize there were different caps for the JD40. It would indeed be a simple mistake causing all this frustration and that sure would explain why I could not get the timing right. I have ordered the 6 volt cap and will let you all know how this story turns out when it arrives

 

[Jim.ME]

A key missing piece of information.

The Waterloo tractors used a different cap as they were 12 volt and often if people ask for a 12-volt cap because a Dubuque tractor was converted to 12 volts, they end up with the wrong cap. The cap does not change just because the voltage changed. Note the clip locations compared to the terminal locations

 

[Fixingfarmer]

So that would make it 90 degrees off because of the clip location. That’s a good piece of knowledge to file away.

 

[Jim.ME]

So that would make it 90 degrees off because of the clip location. That’s a good piece of knowledge to file away.

And if I remember right something about the positioning that makes it so that you can't make the Waterloo cap work to fire more than one cylinder or the other. Not certain on that for sure, but that is what I remember.

Getting that cap has been mentioned a number of times on the jdcrawlers site by guys that did a 12-volt conversion and asked for a 12-volt cap, installed it and had a no start. Some parts books list them as 2 cylinder 6-volt cap or 12-volt cap, which is part of the issue. Points, condenser, rotor and cap work on either voltage, and stay the same when converting to 12 volts.

 

[Fixingfarmer]

That is a little baffling on the parts side why it’s listed that way

it makes me wonder what you would get if you ordered a distributor cap for a late B where it’s Waterloo but I believe 6 volt if its original. Something to watch out for

 

[Jim.ME]

Best to use the actual part number from the JD parts catalog and have it crossed. Or see that it is for the model of the tractor not just listed as 2 cylinder and a voltage.

 

[FarrviewSouth]

Btw yes that was part of what was driving me crazy. I could set it to fire one cylinder dead right but then no way could I get it to fire the other cylinder even close…….must be the wrong cap

 

[Jim.ME]

Btw yes that was part of what was driving me crazy. I could set it to fire one cylinder dead right but then no way could I get it to fire the other cylinder even close…….must be the wrong cap

The pictures I posted should let you see for sure.

 

[MikeinKy]

I have converted several 40's and 420's to 12 volt and always used the original distributer cap. I thought there was only one

 

[Jim.ME]

I have converted several 40's and 420's to 12 volt and always used the original distributer cap. I thought there was only one

The two cylinder tractors built in Waterloo used a different cap than the Dubuque built two cylinder tractors. The distributor cap does not get changed in a 6 to 12 volt conversion; the cap does not care about the primary voltage it handles spark voltage.