Replacing rocker arm needle bearings with bushings?

[swampbuggy]

Gregsdart, if you are gonna try a bushing type bearing, i would highly recommend contacting CHE and see if they can help you. Mark H.

[swampbuggy]

CHE Precision, 805-499-8885 0r sales@cheprecision.com Mark H.

[SupStk]

Even after installing bushings some provision will have to be made for side load thrust on the rocker body.

[cjperformance]

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!!

Are you able to pressure feed the rocker shaft? That would be a great addition.

[SchmidtMotorWorks]

This is a bushing material that I have seen used successfully in automotive engine valve-train applications with low oil pressure and high loads.
I have not found a supplier for it though.
If anyone does find a supplier for that, please post it up.

Bushing
Cr 0.682
Mn 0.064
Fe 0.126
Co 0.084
Ni 7.18
Cu 91.85
Zr 0.009

As an alternative, one of the ampco materials, will get the job done.

https://www.ampcometal.com/

[gregsdart]

Thanks for the info on bronze alloys and possible suppliers. That is a lot of help, since i am green in all this!

[Adger Smith]

I run a Splayed Valve V-6 and it has been hard on Jesel rockers needle bearing cages.
I found a replacement bearing that is made with a thrust on one end. I kept track of which way the rockers broke
and installed the thicker thrust side of the new bearing on the side that most often fails.
It pretty much stopped rocker arm needle/cage failure. They were in the bearing book. I will try to get the number
from my shop tomorrow and post.

[gregsdart]

Mark H, thankyou for the info on CHE!!!

A gentleman that owns the business CHE in cali was kind enough to talk to me about my problem. He developed a proprietary bronze bushing alloy that would stand up to the punishment of bushed, Hemi SS rocker arms, hi hp LS rockers, Isky EZ roll bushings, etc. He uses bar stock to make parts like i would need to bush my Jesel rockers. He mentioned Jesel wasn't interested, even though he has been contacted by Jesel customers that have the same issue as me.
The problem is pressure on the bearing cage,plus a twisting load on a bearing not designed for it. The force from the pushrod is offset outside of the bearings. Just like all materials, all the parts under load compress, maybe ever so slightly, but they have to, or they shatter. Soooo, apply enough shock load, and eventually anything will deform enough to put too much load on one edge, and starts to fail. I see the bearings start to gall the shaft on the outer edge, confirming the twisting diagnosis.
He said i was on the right track using bronze washers between the rockers and the rocker bar to eliminate side loading on the offset intake needle bearing cages.
As for bushings, the special alloy with a wide threaded grove in it to allow oil to enter would work. The problem is, he is swamped with work and a short run of bushings would be quite expensive. So that takes me back to having to use the needle bearings. He did suggest i do two things. Try and fit a wider bearing on the pushrod side of the intake rocker, and groove the washer to allow oil flow to the bearings.
I really appreciate the time he took to help me out. I learned from someone that had solved my very problem exactly what is going on, and what would be needed to step up to a more durable rocker capable of taking more punishment than the rockers can handle as built.
Since a lot of guys are not having the same issues, i pont the finger at having used some brutal cam lobes, maybe not a big enough pushrod, and lifters not up to the loads i threw at them.
The changes since the majority of failures are; new inverted flank cam from Mike Jones. It has very long lash ramps to minimize shock load. EZ roll Isky bushed lifters. 7/16 minimum diameter tool steel pushrods. PAC 1228 springs which provide the same loads as the 948 comps but weigh less and have a higher frequency. Since i don't race a lot, if i can get 75 to 100 runs out of this setup, i will be somewhat OK with running the needle bearings and washer combo. I have been looking for info on this problem for some time, and really appreciate it when someone takes time away from thier swamped business to talk to me!


Edited by gregsdart (11/06/18 01:58 AM)
_________________________
GREG
Educated at SHK U
Measure with yardstick
mark with chalk
cut with torch!



528 cubic inch alky injected 440-1 wedge, 3055 race weight.
8.779 at 153.16 mph. 1.289 60 ft. density altitude 1617 feet. Best 60 ft 1.24

[Adger Smith]

The Timken number for the bearing that fits my Jesel rockers is B-912
It is .750 in length and has a real thick race for the thrust of the bearings/needles on one end.
On the other end it has a thin rolled flange that captures the needles just like the regular bearings.
They have different lengths in the Timken catalog. This one fits my rockers.
I built a fixture for pressing them out and the new in. Can be done in a small vice.

[Adger Smith]

Jesel Rocker Bearing

[JoePorting]

Wouldn't it be easier and cheaper to replace the cam with something more conservative? It might actually run better. If your current cam is breaking your valve train, then it might be causing the valves to bounce.

[Keith Morganstein]

The Timken number for the bearing that fits my Jesel rockers is B-912
It is .750 in length and has a real thick race for the thrust of the bearings/needles on one end.
On the other end it has a thin rolled flange that captures the needles just like the regular bearings.
They have different lengths in the Timken catalog. This one fits my rockers.
I built a fixture for pressing them out and the new in. Can be done in a small vice.

That’s awesome. I’d be trying that for $5 a bearing!

[gregsdart]

Adger, thanks for the picture and info on the thick side. I have been rebuilding my rockers myself, but Jesel never said a word or send any instructions with parts i bought from them. I bought new bearings locally and was able to get some 5/8 wide bearings to replace the 1/2 inch ones on the pushrod side of my intake rockers.
Joe, On the cam and other parts, i have replaced everything except the rockers. The piggy bank is empty, but all the new parts are better. As far as running better, the car picked up maybe 30 hp with this new inverted flank cam and other parts. I am happy with the power level, given the level of sophistication this motor has. No thermal coatings, crank not knife edged, intake manifold is off the shelf, no step headers, straight somewhat short collecters. With a max of 399 cfm intake flow from indy 440-1 heads 528. On injected alky. Car has gone what is in my sig , 8. 76 at 153 with a 60 ft that was .04 slow,at 3050 lbs.

[MadBill]

Alternatively to 'unobtanium' CHE custom bushings, I'm sure a little research would reveal some good commercially available candidate parts/materials, perhaps with 'close enough to adapt' dimensions, but at worst machined up from solid.

[fullpull]

I have had the same problem and tried the timken b -912. It did not work. I'm posting this because a series problem developed when I tried it. After a run(truck pull) I pulled valve cover and discovered some little tiny pieces of metal that I have never ever seen before. Upon further investigation, I discovered that they were tiny tapered pieces off the ends of the needles. The tapered ends on the needles, that are used to contain them in the bearing shell,broke off. Lots of them! Jesel's proprietary bearings ,which have flat ends on the needles and are not trapped, do not have them for a reason. Just posting this so if you try this route, please be careful.