1206 injection pump timing off, can I jump the pump drive gear. Update added

[pirlbeck]

I have a 1206 that starts very hard and the injection pump is timed at 21 degrees before TDC instead of 8 that the spec calls for, and that is with the pump fully rotated to the end of the slots. If I pull the pump and drive adapter back until the pump drive shaft is out of the injection pump drive gear will, I be able to move the injection pump drive gear out from the idler gear enough to jump it a tooth (or two?). I don't really want to pull the timing cover if I don't have to.

I have never had a reason to try this before, but I am hoping someone else has.

Thanks!

[1967806]

1 hour ago, pirlbeck said:

I have a 1206 that starts very hard and the injection pump is timed at 21 degrees before TDC instead of 8 that the spec calls for, and that is with the pump fully rotated to the end of the slots. If I pull the pump and drive adapter back until the pump drive shaft is out of the injection pump drive gear will, I be able to move the injection pump drive gear out from the idler gear enough to jump it a tooth (or two?). I don't really want to pull the timing cover if I don't have to.

I have never had a reason to try this before, but I am hoping someone else has.

Thanks!

I dont think so. The shaft coming out of the engine stays with the engine when you take the pump off if its like an 806. I think the housing the pump bolts to has bearings in it and seals. You may have a shaft/key issue going on. I'd pull the cover off the front of the on the front in front of that pump drive and look it over where the gear and shaft are keyed. 

[FarmerFixEmUp]

Not sure if you pull off the whole drive housing if there's enough wiggle to make it jump or not.  May just have to try. 

[pirlbeck]

Well, I have an answer and it is not what I was hoping for. Even with the injection pump off, the drive housing and the drive housing adapter plate off, there is still not enough movement of the gear to disengage the gear teeth and jump the drive gear on the idler gear. It looks like we are going to be rolling the front end ahead and pulling the timing cover.

This is probably the right way to do it, as then I can make sure that the camshaft is in time.

Thanks for the replies!

[HydroTek]

Wont make the engine start any better tho

That 21 degrees should have made the engine clatter a lot -- did it ?

Have to ask this stuff
-- you are turning the engine clockwise to get to the marks ?? right
-- flywheel marks are to the centerline of the crank and the centerline of the cover bolts -- pointer may be bent
-- advance in the pump is fully at the resting position ? -- RoosaMaster pump ?

[mrfred54]

Be best to remove front cover. Back in the mid 70’s I had a 1206 that had been overhauled by the customers mechanic. New cam and gear was installed at that time. Tractor ran pretty good under load but always started hard, he always used either to start. After bout a year of trying to figure out the hard starting, he wanted me to check it over and after he told me the whole story I decided to check the valve timing to crank degrees and it was off by quite a bit. Pulled front cover and crank and cam gears were aligned correctly with the marks but the valves were off. After scratching my head for a while I decided to remove the cam gear and rotated it one tooth and the valves were now in time. Had to turn pump gear also so the pump could be set to 8 degrees. After contacting IH bout the cam gear being marked wrong they advised me that there were about 20 to 30 gears that were wrong but were supposed to be thrown away but a few got out. They did refund the customer bout $500 so I guess it was better than a kick in the teeth. My question is how long have you had this tractor and how did it get set to 21 degrees??? Has the engine been apart lately??

[DirtBoyz07]

You will need to pull the front cover to change the injection pump drive gear . Time your pump to 6 degrees to BTDC , this will help a bunch . Someone might of changed out the motor at some point and it could have been a D 361 out of a 806 that originally came with a IH / RD injection pump . When those got changed over to the Rosa Master IH made an adaptor for the drive gear and somehow it was put together wrong , just a guess .

Danny 

[Injpumped]

That's a lot of work to go through, if all that is wrong is someone did a poor quality rebuild on the pump. So many people out there doing shoddy work, you never know. If it's put together wrong, the mark can be in the wrong spot. I just don't know enough back story, but it used to run at some point correctly, until someone "fixed" it lmao! Too bad it wasn't an RD conversion, at least the drive adapter for those have a bolt on hub and the gear is slotted for a lot of adjustment. 

[dale560]

Not a given all the time but one tooth on a timing gear is between 11 and 15 degrees usually. That is a generic amount I have found over the years. Like Ed mentioned the injection pump could be assembled incorrectly or you will have to pull front cover. And at that point would check that TDC matches flywheel and timing gear pointer. Use a dial indicator through injector hole is proper method. But a cleaned welding rod and finger pressure while turning engine will get you close to tdc. Then at this point look at your rocker arms if number one is on power stroke. The exhaust valve on six should be just closing and intake on six just starting to open. In otherwords both rockers one number one should be loose and just barely tight on six. This will tell you if valve train is in time. Tractor will definitely start better at correct timing. 

[Diesel Doctor]

The internals of a Roosa Master only allows it to be in time or 180 degrees out. 

It has to be the timing gear or idler.

I'm getting old and working off a failing memory.

There is a steel cover ahead of the diesel pump so the pump adapter and seals can be removed.

But, I don't think any changes can be made to the timing gears. 

Back to pulling the front cover?

 

 

[HydroTek]

I would want to verify that the timing mark in the pump was in the correct place before messing with the gears

if you dont know how to do it -- then remove the pump and take it to a shop 

Unless one knows the history on this tractor -- it is all guessing

govenor flex ring is likely gone anyways , and the pump as to be disassembled for that 
-- will be a good time to verify the timing marks at that time
-- also if the advance in returning to home position 

[Injpumped]

I have seen "rebuilt" pumps that had all kinds of wrong, or incorrectly assembled parts in them, making the timing mark be totally irrelevant, or even in the wrong spot. Not everyone who "rebuilds" pumps knows exactly what they are doing. Again, make absolutely sure the pump is 100% correct. You'll really be happy after making the gear train allow the pump to be timed only to find out it still runs terrible. The odds of someone having taken the gear train apart, and misassembling it is lower than the pump being mis-assembled, but nothing surprises me anymore! lmao!

[dale560]

On my dad’s 806 that’s been on farm since new. We had the idler bolt loosen on idler gear. I was planting corn with tractor came to end row idled tractor down and died out. Wouldn’t start again. Eventually it started and we run it to yard. I don’t know how we diagnosed it but the first thing we took timing cover off and fixed it. Maybe we had pump off and noticed gear was loose. I don’t think the tractor had anything done to timing gears before that. This was in 1990 so tractor was 23 years old.

[dale560]

1 hour ago, Injpumped said:

I have seen "rebuilt" pumps that had all kinds of wrong, or incorrectly assembled parts in them, making the timing mark be totally irrelevant, or even in the wrong spot. Not everyone who "rebuilds" pumps knows exactly what they are doing. Again, make absolutely sure the pump is 100% correct. You'll really be happy after making the gear train allow the pump to be timed only to find out it still runs terrible. The odds of someone having taken the gear train apart, and misassembling it is lower than the pump being mis-assembled, but nothing surprises me anymore! lmao!

I would strongly suggest you do this first. If you want to rule out timing gears. Roll tractor up on tdc and make sure valves are in right spot as explained. 

[Jeff-C-IL]

IDK where this tractor is at, but if anywhere near northern IL  -  just take the pump to InjPumped.    Then you know what you got.

[pirlbeck]

I do know how to time an injection pump, I have been working on diesel equipment for over 50 years, I just never had the need to try to jump the drive gear on a 361/407, so I didn’t know if it could be done without pulling the timing cover.

I know nothing about the history of this tractor, I bought it at least 5 years ago with the intention of taking it and another 1206 I have and making one nice one out of the 2 and selling the left over parts. Until a month ago, it had not been run it was unloaded and parked. I have since purchased a 1456, so I would rather restore it and sell the 2 1206’s. I just want to get this thing to start without either at least when it is somewhat warm out or a the very least after it is warmed up so I can sell it.

[HydroTek]

Jumping the gears without first knowing the timing of the pump is foolish -- if you have been 50 years , you know this 

if the pump is that far advanced , should have serious pinging in the engine as it is accelerated 

[pirlbeck]

If we would have been able to jump the gear it would’ve been the quickest, cheapest, simplest fix to try first. Once we knew we couldn’t jump the gear that changed things. 

[pirlbeck]

Just now, pirlbeck said:

If we would have been able to jump the gear it would’ve been the quickest, cheapest, simplest fix to try first. Once we knew we couldn’t jump the gear that changed things. 

13 minutes ago, HydroTek said:

Jumping the gears without first knowing the timing of the pump is foolish -- if you have been 50 years , you know this 

if the pump is that far advanced , should have serious pinging in the engine as it is accelerated 

And yes , the engine did sound like the timing was advanced.

[stronger800]

But you know you can’t simply jump a gear, as when the drive adapter and pump are removed, the gear sits right there in its cavity with very little room to move. If there was room, stabilizing that gear so that it didn’t move, would be a concern we would all be aware off 

[HydroTek]

The gear will not turn -- but will fall back just enough to allow the engine to rotate 

[pirlbeck]

We jumped the injection pump drive gear 2 teeth, got the pump timed to the 8 degree spec and it stars and runs amazingly well. I know it is not the middle of winter but these 1206's were never know to be great starters, but it fires right up now without either which is a tremendous improvement from not even starting shortly after it was shut off.

The injection pump shows no signs of having a bad governor cushioning ring, no rubber particles in the timing window or fuel return check valve and it does not have the gallop at part throttle typical with a failed cushioning ring, so starting with an injection pump rebuild would of been a waste of money and would of fixed nothing.  

[dale560]

5 hours ago, pirlbeck said:

We jumped the injection pump drive gear 2 teeth, got the pump timed to the 8 degree spec and it stars and runs amazingly well. I know it is not the middle of winter but these 1206's were never know to be great starters, but it fires right up now without either which is a tremendous improvement from not even starting shortly after it was shut off.

The injection pump shows no signs of having a bad governor cushioning ring, no rubber particles in the timing window or fuel return check valve and it does not have the gallop at part throttle typical with a failed cushioning ring, so starting with an injection pump rebuild would of been a waste of money and would of fixed nothing.  

Run it up on the valves and you will be sure it is in time. Number 6 exhaust just closing and intake opening you should be right on tap for one. I usually stick a rod or screwdriver in injector hole to find the spot of no movement on one and you should set your  pump timing around that position if timing marks line up.  Every Cummins 855 has had the accessory drive off and if it isn’t in time your inj and valve sets are off so it’s standard procedure to make sure tdc marks are right on those engines. A 1206 or 1256 will start very good with proper inj pressure, correct timing, valve protrusion in the head.

[dale560]

6 hours ago, pirlbeck said:

We jumped the injection pump drive gear 2 teeth, got the pump timed to the 8 degree spec and it stars and runs amazingly well. I know it is not the middle of winter but these 1206's were never know to be great starters, but it fires right up now without either which is a tremendous improvement from not even starting shortly after it was shut off.

The injection pump shows no signs of having a bad governor cushioning ring, no rubber particles in the timing window or fuel return check valve and it does not have the gallop at part throttle typical with a failed cushioning ring, so starting with an injection pump rebuild would of been a waste of money and would of fixed nothing.  

How did you jump the gear able through the inj pump mount or did you have to remove timing cover 

[pirlbeck]

15 hours ago, dale560 said:

How did you jump the gear able through the inj pump mount or did you have to remove timing cover 

We removed the timing cover, the gear just will not move enough to jump the teeth with the cover on.

And to answer your other question, one of the very first things we did was confirm valve timing along with setting the valve lash. And when we had the timing cover off, we checked the crank and cam gear marks for alignment.