Rocker arms

[Opelmister]

Hi all,

I've been having loud tapping noise and I was hoping that the rocker arms were loose. My question is how tight do you tighten them because they are really loose. I tighten them and noticed that the engine now runs rougher then before and I think I tighten them too tight. However I still have one tapping. Can someone help a novice.

[hrcollinsjr]

Originally Posted by Opelmister Hi all, I've been having loud tapping noise and I was hoping that the rocker arms were loose. My question is how tight do you tighten them because they are really loose. I tighten them and noticed that the engine now runs rougher then before and I think I tighten them too tight. However I still have one tapping. Can someone help a novice.

First, you need to know which type of lifter you have assuming that it is a 1.9 engine. This will determine the adjustment procedure. Second, try the search feature of this site for additional information it works really well. There is information already here to help you determine what type of lifters you have and proper adjustment of the valves and ALMOST anything else you would care to know about your car.

HTH,
Harold

P.S. Welcome to a great community!

[GTJIM]

Over the years the rocker nuts get loose on the threads after many adjustments ... and keep coming loose. They are just like other GM rocker nuts ... squashed a bit out of shape to be tight on the thread.

HOWEVER - they are M10 X 1.0mm pitch threads and about the only US motor that has that size nut thread is the 2.8L/3.1L/3.4L 60 degree GM V6 motor.

Adjustment depends upon hydraulic or solid lifters - so you need to know what your motor has.

Hydraulic lifters rend to run rough after adjustment if they have been loose for a while because the lifter has had its internal hydraulic bits moved from where they have 'worn in'. Hydraulic lifters run at 'zero lash' ... just like Chevy hydraulic ones.

Solid lifters need valve clearance ... just like any solid lifter cam. Opel standard solid lifter cams run 0.012" clearance on both inlet and exhaust.

HTH - ask more questions if you need to - and search for other threads about valve adjustment.

[Opelmister]

Originally Posted by hrcollinsjr First, you need to know which type of lifter you have assuming that it is a 1.9 engine. This will determine the adjustment procedure. Second, try the search feature of this site for additional information it works really well. There is information already here to help you determine what type of lifters you have and proper adjustment of the valves and ALMOST anything else you would care to know about your car. HTH, Harold P.S. Welcome to a great community!

Thanks for your help and your right I did find information about solid lifters and hydraulic lifters. I just hope I have the original head and motor on this car.

[Opelmister]

Originally Posted by GTJIM Over the years the rocker nuts get loose on the threads after many adjustments ... and keep coming loose. They are just like other GM rocker nuts ... squashed a bit out of shape to be tight on the thread. HOWEVER - they are M10 X 1.0mm pitch threads and about the only US motor that has that size nut thread is the 2.8L/3.1L/3.4L 60 degree GM V6 motor. Adjustment depends upon hydraulic or solid lifters - so you need to know what your motor has. Hydraulic lifters rend to run rough after adjustment if they have been loose for a while because the lifter has had its internal hydraulic bits moved from where they have 'worn in'. Hydraulic lifters run at 'zero lash' ... just like Chevy hydraulic ones. Solid lifters need valve clearance ... just like any solid lifter cam. Opel standard solid lifter cams run 0.012" clearance on both inlet and exhaust. HTH - ask more questions if you need to - and search for other threads about valve adjustment.

Thanks for the info. I think what might have happened in my case is that I thought they were hydraulic lifters and I tighten them to tight that it caused the valves to stay open just enough to cause the motor to idle too rough. I will check them tonight to see what I actually have. Boy I have a lot of fun work to do to get this car back to original. I think I will be spending some $$$. Oh well it just my hobie. Thanks again.

[Anonymous D]

RE: "Hydraulic lifters rend to run rough after adjustment if they have been loose for a while because the lifter has had its internal hydraulic bits moved from where they have 'worn in'. Hydraulic lifters run at 'zero lash' ... just like Chevy hydraulic ones."

Incorrect. The factory manual specifies Opel CIH engine hydraulic valves are to be set at zero lash, plus one full turn (360 degrees) tighter. In actual practice, however, it has been determined that 3/4's of a turn (270 degrees) works better.

Reference (June 2006, 1st download link):

Engine

[GTJIM]

Originally Posted by Anonymous D RE: Hydraulic lifters run at 'zero lash' ... just like Chevy hydraulic ones." NOT Incorrect. The factory manual specifies Opel CIH engine hydraulic valves are to be set at zero lash, plus one full turn (360 degrees) tighter. In actual practice, however, it has been determined that 3/4's of a turn (270 degrees) works better.

... That is what "zero lash" means to me Anonymous D!!

Chevy hydralic ones also have the nuts tightened between 1/2 and one turn.
Just trying to relate it to others non-Opel experience ......

IMHO UPMO

[Anonymous D]

RE: "... That is what "zero lash" means to me"

"Zero Lash" is a standard term, meaning no clearance between pushrod and lifter (in the case of an Opel CIH, measured at the rocker arm and valve tip).

But "zero lash" is not the setting for an Opel CIH. On a hydraulic lifter, it's "zero lash" plus a full turn in (factory specification), or 3/4's of a turn (street experience).

Words can mean what they mean to anyone. (The question has been asked, what if "C-A-T" really spells "DOG" -- to quote Ogre, in "Nerds 2").

However, for practical instructions, terms should relate to their standardized usage. Otherwise, a reader would implement incorrect instructions, based on advice read here.

[GTJIM]

The hydraulic lifter is one of the most complex components of an internal engine with a multitude of moving parts with the main purpose of maintaining zero lash.

To maintain zero lash the hydaulic lifter has an internal spring which is pre-loaded to take up changes in valve train component length due to thermal expansion.

This pre-loaded internal spring pushes the components firmly against the valve tip to remove any lash in the system. When the engine is running, on engines with hydraulic lifters, oil pressure fills up the lifters to maintain zero lash in the valve train. This results in quiet operation.

As the speed of the engine increases the lifter eventually fails to follow the cam profile exactly, the lifters pump up to eliminate the tiny amount of resulting extra clearance, and eventually hold the valves slightly open to act as an engine speed limiting device.

Seems clear to me .....