JD 350 fuel injector timing

[Don2018]

I have a straight 350 crawler from 1966. I removed the fuel injector 2 weeks ago to replace both of the throttle shaft o- rings due to nuisance leakage. This was my first time ever removing an injector pump. I barred the engine over and installed the pin in the flywheel for TDC and noted that the cam timing lines lined up nicely in the timing window. I removed the pump and replaced the internal throttle shaft o- rings. I did not wire the throttle in the wide open position. I didn't do enough you-tube study prior to reinstallation and unknowingly "rolled over" the first umbrella seal on the pump drive shaft. Ran it for about 45 minutes and realized fuel was being pumped into the crankcase. I have now removed the injector pump again with the flywheel pinned at TDC and just installed 2 new umbrella seals. SO NOW HERE IS MY PROBLEM. The "dot" stamped into the end of the pump drive shaft is at about 5 o-clock (if looking from the operator seat) and the dot stamped inside the injection pump with the cam timing lines lined up, is at about 12:30 (when looking into the pump) leading me to believe that I am 180 degrees off. When I turn the dot inside the pump with a screw driver to align with the dot on the drive shaft I have to turn it about 180 degrees and then the cam timing lines are no longer synched. Not even close btw. The movable cam timing line is no longer even in view. The small bit of adjustment you can achieve by rotating the pump during installation is not even remotely sufficient.
What have I done and what do I do?
Thanks
Don
I should also mention that the machine started great and ran great while it was pumping fuel into the crankcase. I also wired the throttle shaft into wide open position prior to removal this time. I should also mention that my 80 year old mother was the one who pinned the flywheel at TDC while I was barring over the engine. I checked her work and it seems right but I just read on here that sometimes that pin insertion can be misleading. I have tried to bar the engine over with the pin in place and it doesn't seem to budge so I believe mom got it right.

[Jim B]

I would guess you pined it with #4 on compression, not #1 cylinder. A 4-stroke engine is only on compression every second rotation of the crank. 1 and 4 are companion cylinders (both at TDC at the same time) one on compression entering the power stroke, one at the top of the exhaust stroke and starting the intake stroke. one revolution of the crank reverses what they are doing. I would turn it over 1 revolution and see if things line up. Checking to see that the #4 valves are on the rock and the #1 valve rockers have free lash would confirm, if you want to remove the rocker cover.

[B Town]

Hey Jim, he is working on a 3 cylinder, 350. I don’t believe a 4 cylinder 350 was built.

[Don2018]

Yes it is a3 cylinder and as far as I know if this engine is pinned, it will be #1 TDC.

[Jim B]

Hi Bruce,

Thanks for correcting me, I totally spaced that out as far as the number of cylinders and checking the companion cylinder. The part that the timing pin will go in every rotation but #1 is only TDC on compression every other rotation still holds.

If things are correct, one should be able to line the dots up and install the pump, even if the timing marks are visible, and it will be right.

[Jim B]

Don,

Sorry about my screw up on the number of cylinders.

Regarding the timing pin. A four-stroke engine (regardless of the number of cylinders) only fires every other rotation of the crank.

The rotations and strokes in each:

First crank/flywheel rotation:

1. Intake stroke is piston going down to pull fuel and air in.
2. Compression stroke the piston is going up compressing the fuel/air mix prior to firing. TDC at the top of this stroke is the timing point.

Second crank/flywheel rotation:

3. Power stroke is when the fuel air mix is ignited and the burns pushing the piston down.
4. Exhaust stroke is the piston going up pushing the burnt combustion gases out in preparation for another intake stroke. If the pin is installed at TDC of the exhaust stroke you will be 180 degrees out of time.

[Don2018]

Hello Jim B
Are you saying that I should rotate the flywheel 1 more rotation, pin it, and then the engine and pump should now be timed properly. This would mean the 2 dots and the cam timing lines should line up??

[Jim B]

Yes, rotate it one revolution and see if things line up then.

The pin will go in the flywheel timing hole every revolution of the crank. Just because the pin goes in does not mean it is on the correct stroke to time the engine.

[Don2018]

Ok here I go! I’ll let you know
Thanks

[Don2018]

Ok well that seems to have worked. After 1 more rotation, the 2 dots now line up nicely! Thank you JimB!
It’s disappointing that the maintenance manual doesn’t reference this situation Seems to me like that should have been explained right away. I’ll make a note of it and place it in my manual
Time to put the pump back. I’ll let you know how it goes!
Thanks again

[Jim B]

Glad to hear it looks like it is going to work.

As for it being in the manual, you have to remember these manuals are written for dealer mechanics, not the DIY market. This is something a technical writer would expect a dealer mechanic to know and would not necessarily include in the write up, where a DIY automobile manual will often explain things in greater detail. This cycle scenario is the same for all four-stroke engines, even though timing marks line up every revolution they only fire every other rotation, regardless of number of cylinders or the brand. All two-stroke engines, like chainsaws and the old "jimmy" diesels, fire every revolution.

[Don2018]

Yes I’m definitely an amateur. The pumps back on and am currently hooking everything back up

[Don2018]

Ok injector pump back on successfully. Took about 5 seconds of key on for a good start. Ran a little rough for about 15 seconds and then evened out and runs perfectly now. No injector bleeding necessary Hit the key now and it starts immediately like it always has . I Let it idle for half hour and no fuel in the crankcase
Big thanks to JimB and this forum!!
Relief
Thanks

[Don2018]

Also a shoutout to BTown
Thank you sir

[Jim B]

Good to hear you got it and aren't still looking for the fourth cylinder I mentioned.