Replacing rocker arm needle bearings with bushings?

[gregsdart]

I have posted before about my problems with losing needle bearings in offset intake rockers, am again considering a switch to bushings. Anybody done it? I know very little about bushing material, ability to handle the load, etc. I am using BBmopar Jesel offset .800 rockers, large roller cam springs with 800 lbs open pressure. Any help appreciated.

[BobbyB]

Do you consistently lose the needle bearings on the side that is loaded the most due to the offset? (In a non offset rocker the load is evenly distributed across both needle bearings, not so with offset rockers.)

Have you found any bearings showing spalling or flaking before they totally fail?

Have you talked to Jesel about your problems?

[JoePorting]

Maybe the cam is too aggressive and is beating up your valve train.

[SupStk]

I have posted before about my problems with losing needle bearings in offset intake rockers, am again considering a switch to bushings. Anybody done it? I know very little about bushing material, ability to handle the load, etc. I am using BBmopar Jesel offset .800 rockers, large roller cam springs with 800 lbs open pressure. Any help appreciated.

Would it be possible for you to post photos of your assembled valvetrain and of the damaged components?
Are you running external oilers?

[mag2555]

Can I ask what heads you are running and what you are buzzing the motor to?
are you failing both Intake and Exh rockers?
What duration and Cam lobe lift and valve lift you are running?

[408swinger]

I work for a Acura ,Benz , Porsche ,Rover and Jag dealership ... back when the Acura RSX type S came out with a close gate 6 speed we had several engine failures. The owners said they just died but the engine management systems told a different story ! They recorded RPMs of 11k+ !
Owners were powershifting and missing gates (dropping a gear)thus mechanically over revving the motors.
Spun the bearings out of rockers , snapped heads off valves... not pretty.

NO WARRANTY...LOL

[gregsdart]

Big block mopar 440-1heads. 7500 rpm, 7700 r ev limit. The offset rockers are being slammed against the C clip that goes against the needle bearing cage, which is supposed to keep the rocker body in position. Trouble is, it wears out the Cclip, and cracks or breaks the needle bearing cage, which seizes the needles and starts the catastrophic failure, ending in a siezed oil pump, ruined bearings, and, well, you see what else could follow.
The cam was a .775 lift, older superstock type lobe profile,pretty harsh. Springs are 325 on the seat, 825 over the nose, 7500 rpm, stainless 2.25 valves, mopar big block, very heavy pushrods.

[rustbucket79]

Any room to put hardened washers between the clips and bearing cages?

[gregsdart]

No room to add washers and retain the original parts.

[Momus]

Nickel bronze bushes in the arms and a proper thrust washer arrangement. Rocker manufacturer should be onto this. Needle rollers are a light duty bearing in this application.

[Geoff2]

Have the rockers bronzed bushed.

[gregsdart]

I am going to call ASB bearings in the morning and see if they have an alloy of bronze that is best for this app. If they do, i can trim to length and press them in, maybe have to size them also. There is a trench cut in the middle of the rocker arm for lightening, and it is the perfect spot to drill a hole through after pressing in the bushing. I am thinking a .125 hole ought to be enough with both spray bars and oil through pushrods providing lots of oil. Those slots collect oil, hopefully enough. I may also be able to get oiling groves cut in the bushings at an angle as well to help get the oil down where it needs to be. I plan on trying one rocker this way and see how it goes. I will cut the bushing long enough that it will be about .005 narrower than the slot in the mounting bar is. That way i can get rid of any washers. I hope it all holds up!!

[Sparksalot]

In your own words the problem is C-clips with excessive side loading precipitating a failure. C-clips should never experience any moving part against it in a high performance valve train. That's a major clue to investigate. Solving the problem will mean eliminating the culprit: bad design.

Solid bushings and solidly anchored thrust bearings to react the side loads of your rockers are big improvements.

[Keith Morganstein]

I've had good luck with offset rockers that are aluminum bodies, directly on the shaft. Open load around 650 though, not 800.

[Keith Morganstein]

I am going to call ASB bearings in the morning and see if they have an alloy of bronze that is best for this app. If they do, i can trim to length and press them in, maybe have to size them also. There is a trench cut in the middle of the rocker arm for lightening, and it is the perfect spot to drill a hole through after pressing in the bushing. I am thinking a .125 hole ought to be enough with both spray bars and oil through pushrods providing lots of oil. Those slots collect oil, hopefully enough. I may also be able to get oiling groves cut in the bushings at an angle as well to help get the oil down where it needs to be. I plan on trying one rocker this way and see how it goes. I will cut the bushing long enough that it will be about .005 narrower than the slot in the mounting bar is. That way i can get rid of any washers. I hope it all holds up!!

Id be worried that the plain bushing with splash/drip lube will fail with that load.