Rocker armś play??

[suburbanK-2500HD]

Hi

i replaced the headgaskets 3 weeks ago, and during dissasembly i noticed what i think is a big play between the rocker arm, and the shaft.
the play is up\down when installed at the shaft.
Itś about 1-1,5mm......:cool:
I talked to the GM dealer i Town, and he says its OK..?
I doubt thatś correct.

Anyone know whats tolerable play..
I got some knocking from the engine that i cant figure out, and wonder if it could be a rocker arm issue.

would this play cause effect loss?

thanks

Børge

[ercaduceus]

What is the condition of the nylon retainers? They may need replaced. Not a bad idea if the valve covers are off anyway.

[suburbanK-2500HD]

the nylon retainers looks fine, i am more worried about the roker arm play.
But ofcourse, if i change the rocker erms i change the retainers too.

thanks

[Robyn]

With the rockers assemblies off the head and just by themselves will see the rockers very sloppy.
The rocker pivots on the lower surface and the two top rails just keep the rocker stable as an assembly.

Once the assemblies are on the engine and the bolts torqued down all the slop will go away.

When you torque the bolts, do so in an orderly fashion from end to end on each aseembly. Do so slowly and if you encounter difficulty stop and let the lifter bleed off.

Once you have all the rockers installed, roll the engine over several turns BY Hand to make sure nothing hits (Valve to piston clearance)

OH BTW the pushrods must be installed correctly. The copper colored end goes to the rocker. Failure to do so will cause excessive and fast wear of the pushrod and the rocker and a costly repair.
Due to wear and such the copper color can at times be hard to see.

Hope this helps

Robyn

[suburbanK-2500HD]

I understand that they can be a little sloppy when dissasebled from the head, but my concern is the play between the arm and the shaft.
1 - 1,5mm. aint that a lot of play.??

I guess the hydr-lifters compensates for som play, but there is a limit..
And dont this cause noise too..

thanks

Børge

[suburbanK-2500HD]

Any knowledge about this anyone.??

have tried asking around, but no one knows for sure.

Thanks

[rhsub]

Rocker arm play on shaft is not important, what you need to check is for excessive wear and scoring on the shaft on lower side (opposite locating button), wear and scoring on rocker arm (3 places) at push rod seat, valve contact and rocker arm to shaft contact.
push rod seat should be a smooth shinny almost mirror like finish
valve contact surface should be smooth
rocker arm contact surface should be a smooth shinny almost mirror like finish and should be same approximate thickness as rest of rocker arm
if any of these surfaces are dull or have deep or excessive scratches replace the rocker arm and the corresponding component "ie" rocker arm or shaft
rocker shaft should have only minimal wear at each rocker arm, should not be able to catch your finger nail on ridge at edge of wear pattern
PS Most people on this side of the pond still measure engine clearences in thousands of an inch
Hope this helps
Ron

[suburbanK-2500HD]

Rocker arm play on shaft is not important, what you need to check is for excessive wear and scoring on the shaft on lower side (opposite locating button), wear and scoring on rocker arm (3 places) at push rod seat, valve contact and rocker arm to shaft contact.
push rod seat should be a smooth shinny almost mirror like finish
valve contact surface should be smooth
rocker arm contact surface should be a smooth shinny almost mirror like finish and should be same approximate thickness as rest of rocker arm
if any of these surfaces are dull or have deep or excessive scratches replace the rocker arm and the corresponding component "ie" rocker arm or shaft
rocker shaft should have only minimal wear at each rocker arm, should not be able to catch your finger nail on ridge at edge of wear pattern
PS Most people on this side of the pond still measure engine clearences in thousands of an inch
Hope this helps
Ron


Best help so far, thanks a lot..

Ok, i discovered yesterday that i have a leaking rocker cover at the turbo side, so i will fix that this weekend, and check for wear as you explained in the valve train parts.

[suburbanK-2500HD]

Rocker arm play on shaft is not important, what you need to check is for excessive wear and scoring on the shaft on lower side (opposite locating button), wear and scoring on rocker arm (3 places) at push rod seat, valve contact and rocker arm to shaft contact.
push rod seat should be a smooth shinny almost mirror like finish
valve contact surface should be smooth
rocker arm contact surface should be a smooth shinny almost mirror like finish and should be same approximate thickness as rest of rocker arm
if any of these surfaces are dull or have deep or excessive scratches replace the rocker arm and the corresponding component "ie" rocker arm or shaft
rocker shaft should have only minimal wear at each rocker arm, should not be able to catch your finger nail on ridge at edge of wear pattern
PS Most people on this side of the pond still measure engine clearences in thousands of an inch
Hope this helps
Ron


Ok, have fixed the oil leak, and removed 1 assembly of rocerarms.
i attach some pics so you can look.
i didnt remove the retainer since i didnt have new ones..

i also pressure checked the injectors at the turbo side. two of them started to spit a little befor reaching pop off, approx 145 bar.
i opened them and cleaned them.
i noticed in one of them it was two pieces of shim/shield? in the bottom, the other one has one.
At the left side i opened one injector, and that one had only 1pcs of this.
What is correct..?? i attach a picture of injector, but it doesnt show this internal part.. the part is installed inside the lower body

thanks

[suburbanK-2500HD]

Picture of injector.

[rhsub]

Borge

Looked at your pictures of rocker arms, not the best wear pattern but the proper way to fix it would be to replace all rocker arms and shaft, these parts all wear and seat into each other, that said truck has 230,000 km and the wear doesn't look excessive I would be tempted to reinstall all parts in THERE ORIGINAL POSITION and drive it. The play between shaft and rocker arm looks normal, rocker arm has constant pressure pushing it up when engine is running. When you bolt rocker arm assembly on to engine check free play of rocker arms, they will probably wiggle a tiny bit, if you can rock the rocker arm easily check push rod for wear, a collapsed valve lifter, worn camshaft or valve for a problem.
Its highly recommended to replace the plastic buttons in the rocker shaft when you are in there because they have a history of failure and as you know they are not that easy to get at
The shim/shield you found in the injector is not something i am familure with so hopefully one of the other members will educate us on them
Good luck
Ron