Rocker Arm Bolts WITHOUT TDC?

[idi_econoline]

OK, so we were reassembling after head gaskets today. My buddy is new to these engines, but otherwise quite competent.

Not long after we got the valve covers back on, Hydro-idi texted me, asking if we'd lined up the timing before torquing the rockers.

News to us. Didn't read da book. Da Book sez line up the timing mark before torquing rockers.

We undid the valve covers, untorqued, lined up the timing, then retorqued.

Big problem? Guessing possible lifter damage?????

 

[IDIDieselJohn]

Line up the timing mark to where?

 

[idi_econoline]

Chilton book said to put timing mark at 11:00 position. I lined it up to the larger of the two timing tubes at that location.

Hey, you have low-mileage early vans?

Didn't notice that before. Again, didn't read closely enough!

 

[IDIDieselJohn]

I'd like an answer. In the coming weeks, i'm doing the IP, and head gaskets on my '85 6.9L van, and upgrading to the 7.3 rockers at the same time.



And yes, i'm a van nut, thanks for noticing

 

[OLDBULL8]

The timing mark on the damper pulley to the 0 mark on the timing plate or put the timing mark at 11:00.

 

[idi_econoline]

So, lifter damage, OLDBULL8? Is it that serious?

If I need to pull the valley pan back off & replace lifters, now is my preferred time!

 

[Sw1tchfoot]

I do not see why it would say to line up the timing mark at one position. In the gas burner world that I am familiar with, you would make sure the lifter is on the base of the cam lobe (not generating any lift) when adjusting or tightening that particular rocker arm. (Not to prevent lifter/valvetrain damage, to prevent misadjustment) Therefore you have to rotate the engine going from rocker to rocker, I do not see how sitting at one timing position would be benificial to adjust all 16 rocker arms because there are surely some valves opening/opened at any single given point, right?

 

[OLDBULL8]

Oh, I don't think so, there not solid lifter, there hydraulic, might just have pushed some oil out of some of them. Retorqiing the rockers was a good thing to do tho.

 

[idi_econoline]

OK, feeling a bit better now.....

 

[icanfixall]

Update to all this fuss. What the book is trying to tell you that setting the dampner timing mark at the 11 oclock position makes it so all the pistons are below top dead center. So now none of the valves will get bent if they are pushed into a piston at top dead center. This is a safe thing to do as some have not done it and no issues were found. I call it insurance. Now about the timing tab located spot welded to the gear cover... That first fat little tube is the top dead center mark. You can verfiy this by cleaning it and feeling the pressed in line at that tube. The other tall skinny tube is where we place the magnetic probe in when we time these beasts. If all the gears are in the covers but the injection pump is not connected you can trun the engine enough to make the rockers tight. You do not need to turn it back for the injection pump connection. That pump will only connect to the gear one way. Its impossible to connect it out of time. Only having the gear one or two teeth off time with the cam gear wil do that... BTW.... These engines will run with the injection pump 180 degrees out of time. This happens because you didn't realize the timing marks on the gears... The crank to cam mark is a dot... The timing mark for the cam to the injection pump gear is the letter Y... Please make sure you understand this because its very tuff to retime the gears once things are bolted up and running poorly...

 

[plywood]

11:00 on the timing mark makes sure that all cylinders are below TDC so no contact is made.

 

[xcite]

timing is set to 1100 oclock position so all pistons are down in the bores as to not possible bend any valves while torqing them down which is possible if the lifters are full of oil. They may not leak down fast enough to avoid hitting the piston.

 

[idi_econoline]

OK, this all does make sense.

So you guys know my next question...

Do I take off the heads to check for contact?

FYI, timing mark was about 1:00 during original torque down.

 

[IDIDieselJohn]

Welll..... put it this way.... would you want to remove the heads inframe in the near future for problems?



...Didn't thinkg so



Better be safe than sorry!

 

[idi_econoline]

And thanks, ICANFIXALL, though the upper timing gear was always in place, and stayed motionless while the IP was out.

I am wondering, though, that if the engine didn't turn from the time the rockers were removed to the time they were torqued, would the pistons not be in the same correct position for their valves??