M1009 rocker arm/timing question.

[Erik Jenkinson]

Im presently replacing my IP and injectors, and am painting my valve covers which were leaking. I noticed while I was in there that those little rocker retainer buttons looked old and brittle, so I replaced those, one rocker at a time. I also replaced the pushrods. I simply removed and replaced them. I have not yet reassembled anything aside from the drivers side rocker arms. I did notice though that the 34 tm says to align the timing marks on the water pump and damper PRIOR to torqueing down the rockers. Is this necessary? I dont believe I might have done anything to throw the motor out of timing, but wanted to check with all of you to be certain.

 

[NDT]

No reason to align timing marks for your valvetrain repairs but it is a good idea to do so for replacing the injection pump.

 

[Erik Jenkinson]

So after I have re-installed the rocker arms, covers etc. I should then align the timing marks, and then install the IP? I was concerned about hand cranking the engine with the IP out. I was under the impression that the indexing pin on the part of the IP that attaches to the timing gear inside would insure that I was getting it back in correctly.

 

[richingalveston]

supposedly you can bend a push rod when torqueing them if you do not have it aligned right when tightening the rocker arms.

I guess you have the water pump removed? if not, you cannot see the dot on the cam pully in order to line it up with the dot on the ip pully.

The crank pully dot lines up with the cam pully dot first and then you rotate the engine around so that the cam pully dot is on top and you line it up with the dot on the IP pully.
IF the water pump is installed then you cannot see the dots.

if you did not remove the timing chain then the cam and crank dots should already be alligned

 

[cucvrus]

Correct. The 3 bolts only align one way. The pin goes thru the oblong hole on the timing gear. That timing gear cannot jump out of time with the front cover and timing cover in place. Good Luck. Use a magnetic 13MM socket or put some tape in a standard shallow 13mm socket if bolts dropping concerns you.

 

[Erik Jenkinson]

I hope I haven't bent one of my new push rods... Although I don't see how, given the fact that I have simply removed and replaced, but then again, Im here to learn. My water pump is still on. Usually I just follow the the TM, step by step. I was just surprised to see the TM mentioning the alignment of the timing marks. I didn't remove my timing chain obviously, so am I in the clear, or should I pull back off my rockers, inspect the rods, pull the water pump, align the marks and re-install?

 

[richingalveston]

as long as you have not disturbed the timing gear when removing the iP . The gear can jump teeth when the ip is removed. there is enough room inside the cover that the gear can move over a couple of teeth and screw up your timing.

If you are certain the gear has not moved, then you can put it back together. As recomended by CucvRus, use a magnetic socket. If you drop a bolt inside the cover, you have to take it apart to get it out.
I do not have a magnetic socket but i have a large magnet i put on my socket extension and it works the same.

To see the dots, you have to remove the water pump backing plate to get the timing set right.

 

[Erik Jenkinson]

I can feel a little play in the gear, but I don't believe it has likely rotated out of time. I actually have parts here to service my cooling system already. So if I start my engine, and indeed the timing has become "off", is that going to cause huge damage, or should I just do the cooling next, prior to attempting to start the engine? Then I can be certain the gear didn't move. For whatever its worth, I don't think I've moved the gear, and I would like to postpone the service of the radiator etc.. But if you guys believe it prudent to pull the cooling system now, I will. Is it worth it? Am I going to murder my motor if I attempt to start it out of time?

 

[cucvrus]

Hey I am going to stand behind my statement that the gear can NOT jump time in the timing cover while the front cover is installed. I have tried to make the gear jump teeth when I was rebuilding these engines. The area is so close it don't allow it. Besides you are pulling back and pushing in. I went to Morristown NJ for 6.2 diesel training. Back in the early 80's every PennDOT truck and all the Municipal fleets trucks were using the 6.2. diesel. When the CUCV's came out I went back and learned more. I wanted to double check my statement. I went down to a scrap M1009 that still has an engine and timing gear in place. I stand behind my statement that there is NO way the gear can come out of time with the water pump and timing cover in place. The space provided does NOT allow it. Not to be a know it all. I just tell people all the time. "Don't worry. There is NOT enough room in there to move the gears out of mesh/time. Back side of timing cover showing water pump attaching bolts. Timing gear as it looks with cover removed. minus the rust yours looks the same. Showing close tolerances and depth of gear teeth.Me trying to force gear upward and skip time. It can NOT be done. That area is so tight and it must be. I remember during GM school. 2 instructors argued that the timing cover should be removed to correctly service and remove the IP. The other instructor said NO change the IP pump and remove the 3 attaching bolts thru the oil fill. This went on for the rest of the day. The next day the model engine in front of the class was apart and the one instructor tried for a hour to skip the time and gave up. Then he said he was afraid technicians would drop the M8 bolt if they serviced the pump thru the oil fill. I have lived dangerously doing this bolting on IP's thru the oil fill for 35 years. I got over the fear and it works every time. I would NOT recommend you use the starter to turn the engine over while the pump is disconnected. But a 15/16" socket on the bottom pulley works every time for me. Good Luck. Torque the rocker arms down and they will tighten the push rods correctly. I wanted to double check myself for good reason. I give 6.2 information to a lot of people. Have a Great Day. Tighten everything up to torque and fire it up. It's a Simple Task. Also hard to imagine they used the Oblong hole for the pump peg.

 

[Erik Jenkinson]

Thank you. Im on it...

 

[richingalveston]

thanks for showing that, I thought it could and always to extra caution to be sure and not let it move. I would put a stick through it and wire it in place if it were being un attended for any amount of time. now i dont have to worry about it in the future