HELP!!! Valve Adjustments, Comp Cams Magnum Roller Rockers??

[JESSE]

valve adjust

guys, i dont know if your doing this but i've seen a lot of machanic's trying to adjust valves and doing it wrong!! what they would do is back the rocker nut until it made noise and then adjust until the noise stoped. which is the right thing to do, then they would try to add the 1/2 or1 full turn while the engine was running which is the wrong thing to do!!!! the proper way is adjust all eight on that side and shut the engine off and then make the final adjustment and put the cover back on and go to the orther side.. i set mine at 1/8 turn and i works for me i hope this helps 😀

 

[85 Cutlass Brougham]

I have the same rockers as you and they will not permit me to put a socket on them unless the valves are closed. I had a similar experience with them jamming the socket in the hole a few times just like you did.

 

[mebe007]

so i take it you adjusted them while engine was not running, well plus you said that in your post.

 

[mebe007]

thanks to those who helped, i got the car running today.

 

[Uncletruck]

Just kind of amazed with all the know how here, that with hydraulic lifters nobody really knows what is going on with the adjustment. Zero lash is zero lash- this is what a hydraulic lifter does. It is designed to maintain zero lash at all engine RPM's and at any temperature. That is a hard job- just take a hydraulic lifter apart some time, and you'll see it's a very complex little device inside.

In order for the lifter to work, it's plunger has to be preloaded with pressure from the pushrod in order for the lifter to fill with oil and maintain the zero lash. So guess what? The setting of the nut is not an adjustment that has anything to do with performance or runability- it is to get proper lifter preload. With a solid valve train it's different. Roller rockers are made to reduce friction with the valve train, but if using with a hydraulic cam and lifters, they still just maintain zero lash. I have never ran across any type of automobile engine, either soild or hydraulic cam where you adjust the valve train with the engine running- which is a good thing as you just get too much oil all over the place. I have a few GM service manuals for the small blocks of late 70's to late 80's eras, and looked but found none where it is said to adjust a hydraulic valve train with the engine running.

I see one consistent mistake made when replacing hydraulic cams and lifters. You have to clean the old lifter bores out really good with solvent in order for the lifter to move properly inside the bore. Give the lifters plenty of time to fill up completely with oil- this sometimes takes several hours of running even if you pre fill the lifters with oil.

I do adjust my ignition timing redneck style 😛 Only because with late 70's to early 80's carbureted GM engines it's about the only way to avoid getting any detonation. (The little chart showing 10-15 degrees BTDC was calibrated for gasoline of that time, and it has changed quite a bit since then) Light detonation was considered normal under heavy acceleration in those days according to GM, but you bump the timing back a few degrees at the cost of MPG, and it is gone. Then pop a Charlie Daniels tape 'n to the 8 track.

-UT-

 

[megaladon6]

well it doesn't take much to over do the preload. and that will screw up the way it runs or bend valves. in my case it bent the valves and i wasn't over-adjusted by much.