Opel GT Forum banner
1 - 4 of 4 Posts

·
Member
Joined
·
433 Posts
Discussion Starter · #1 · (Edited)
Hi All,

I've read the posts here and I've spoken with Roger Wilson. And I'm more confused now than if I had just read CHILTONS and did the damn adjustment.
Again, this is my first time doing a valve adjustment so bear with my ignorance.

Roger outlines the procedure thusly:

Because my engine hasn't been started for some time, he recommends to just make contact with the valve and the rocker.

Start engine and let the hydraulic lifters pump up.

Let the engine warm up and then shut the engine off.

Back off the nuts and redo the adjustment. Only this time, add an additional 1/4 turn after contact.

--------------------------------------------------------------------------

Now CHILTONS and others on this site have said that all that's needed is to make contact (engine hot or cold) and add a full turn. Now I see quite a difference between a 1/4 turn and a full turn. To make matters worse, OGTS says they add a 3/4 turn.

***Also, are there any "pre-flight" check lists before re-starting my engine after replacing the head?

Thanks,

Manny
 

·
Registered
Joined
·
6,344 Posts
Manny, what Roger, OGTS and Chilton's are all suggesting is to "Pre-Load" the hydraulic tappets/lifters, or whatever you wish to call them. The whole idea is to make sure the internal piston is not topped out and eliminating any hydraulic cushion action as the fluid is forced out of the lifter by the action of the valve train. If that happens, it gets real noisy under the valve cover, and engine performance will suffer. To paraphrase a note out of the Toyota Supra maintenance manual, "noisy hydraulic lifters cause no damage to the engine, but are extremely annoying" So, when you "Pre-Load the lifters, do what you feel comfortable with, or go half way between the max and minimum, it won't hurt.

As far as pre-start checklist, normal stuff, belts adjusted, oil, gas, coolant, electrical connections, hose connections, etc. One more time around to double check, then lite it off. ;)
 

·
Old Opeler
Joined
·
5,564 Posts
Adjustment!

The Opel lifters are of the Buick design and require preloading to between 0.020" and 0.060" (twenty to sixty "thou") for correct operation. Since the thread in the adjusting nut is 10mm X 1.0mm pitch and 1.0mm = 0.040" then exactly one turn on the nut puts things at mid-limit of the adjustment range.

The FSM is adamant on this:
"Amply oil respective parts and install in reverse sequence to removal."
(My Note: Use a high pressure oil can to pump VERY CLEAN engine oil into the oil hole in the side of the lifter and SOAK the lifters in engine oil over night.)

"Carry out hydraulic valve lifter adjustment with the engine off: It makes no difference whether the engine is cold or has operating temperature. Set piston of respective cylinder to U.D.C. It is advisable to adjust lifters in the firing order."
(My Note: U.D.C. = U pper D ead C entre IE: Top Dead Centre)

"Back off the adjusting nut at the rocker arm until a clearance exists. Then tighten adjusting nut until any clearances between valve, rocker arm, and lifter are eliminated. Screw in the adjusting nut ONE FULL TURN . The valve clearance is not (My Note: now?) adjusted and no re-adjustment is required"

Who you going to believe ... Opel or ....... ??

'Nuff Said??
 

·
Registered
Joined
·
3,445 Posts
GTJIM said:
......
The FSM is adamant on this:
"Amply oil respective parts and install in reverse sequence to removal."
(My Note: Use a high pressure oil can to pump VERY CLEAN engine oil into the oil hole in the side of the lifter and SOAK the lifters in engine oil over night.)
Would the above apply to NOS lifters as well? I was going to save a set of lifters I got off Ebay last year for an engine rebuild, but since I have found I have a early high compression engine with solid lifters due to a trade, I thought about going ahead and using the NOS lifters on the old engine. The next question would be should I use them on the "old engine" or save them and use them with a "new" cam in the future on the "old" engine with a rebuild. Just thought about throwing this out for some recomendations/suggestions. Thanks, Jarrell
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top