installing rocker arms, quick Q

[Greg5OH]

i read you gotta get the timing mark at 11 oclock position, so all pistons are below TDC. So for these engines we dont need to have the cam on base circle to tighten the rockers?
also, what torque do the bolts go to?

 

[Greg5OH]

also want to comment, that inside of my engine looks MINT. 320k miles on it. no gum, no tar, nothing. i did run auto rx last 2k miles.

 

[icanfixall]

I feel its safer to run the timing marks up to the 11 o clock position. I know this is the safe area but. I have done it both ways without issues of piston and valve kiss. Others have had valves bend because they did not compress the lifters. Its your call but why take a chance of doing damage. I don't have the torque spec handy but can find it later if nobody else comes up with it. I want to say 17 or 27 ft lbs but not sure so please find the torque before doing anything..

 

[ZWilson07]

My book on my 90 is showing 20 ft pounds and that is also what I saw in this thread by the man above himself in a quick search posted before.

http://www.oilburners.net/forums/showthread.php?27294-IDI-torque-specifications

Also listed as 20 ft lbs here

http://www.thedieselgarage.com/forums/showthread.php?t=78234.

My book considers it a valve rocker arm under directions, and listed as valve lever post bolt under specs.

 

[Greg5OH]

thanks, going to do be putting in head studs tonight..withthe head son. many here feel this is not the way to do it, i question it myself sometimes, but eff it, cummins guys do it all the time, and i saw a wirte up how to do it on pwoerstrokes too. follow the oem pattern, center one out, stud in, torque to 90, rinse repeat till all are in at 90 ft lbs, then crank em to desired torque in steps.

no issues with HG or leaking intake gaskets so im not going to mess with it. Plus that snotehr 50-60$ in gaskets + time. and to be honest-I dont want my heads cleaned and inspected, if i found out i have cracked pre cups or something I cant allow myself to run it.. sooo i will assume everything is dandy in there

 

[jhenegh]

Which timing mark to 11? The dampener or the internal one?

 

[Greg5OH]

not sure, i took the damper mark to 11, i assume its the big cut line on it.

 

[icanfixall]

The timing tab has 2 probe locations. We use the tall skinny tube location when timing but... Thats not the top dead center mark. The tdc mark is in the middle of the short fat tube location. You will probably need to clean odd some road dirt to see it. Riotwarrior has a great writeup and pics of this too. So with the damper set for tdc just turn the crank till the damper mark reaches the 11 o clock position. Now every piston is below tdc.

 

[jhenegh]

Excellent! Just got my cam back so stuff will all start going back together.

icanfixall do you have that pic of the timing gears handy? I should probably start a new thread to make sure I've got all the timing gear stuff straight.

thanks

 

[BDCarrillo]

Dot to Dot and Y to Y should do ya up nicely on the timing setup.

For rocker arms I put the zero degree mark at 11 o clock. The cutout on the harmonic balancer is for inductance timing meters hooked into the hole on the timing pointer.

 

[IDIoit]

what kind of cam do they install on these? hyd. rollers?

 

[BDCarrillo]

Yup, hydraulic roller from the factory.

The tight valve clearance to piston face and pumped up lifters can result in unfavorable valve/piston interaction when torqueing the rockers.

 

[icanfixall]

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Heres the cam to crank and the injection pump gear timing. As posted its dot to dot and Y to Y.

 

[Greg5OH]

still a little confused, damper mark being the slot cut in the damper? If so i put it to roughyl 11 oclick and torqued my rockers.

However, unless you swapped cams and didnt time the cam properly., or purposly retarded/advanced it there shouldnt be ANY poiston valve clearance issues. As when the piston is at TDC, or very near it, the valves are closed or almost closed. Even if the lifter was solid (almost acts like it but does have a little bit of give even when pumped up), you are tightening the rocker with the cam on base circle, and therefor the valve should not open.

 

[Black dawg]

It can take awhile for the lifter to bleed down, I usually just tighten rockers till some resistance is felt, then let the lifter bleed down, and then tighten some more. It may take a little while, but eventually they will all be tight, and no worry of pushing a valve into a piston. If you tighten a rocker down, and the lfter is pumped up, you can have contact, even with the cam on base circle.