Rocker Arm Oil Pressure

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tjpatte said:
Rotational on the nose?
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I’m not an engineer so I can’t use the words to describe it correctly, but in essence there is a cross load across the rocker because the adjuster isnt inline with the tip of the rocker.

If you look at the exhaust rocker the adjuster and the tip of the rocker are in line. So the load across the rocker is in line.

I should have written down how it was explained to me but I didn’t. The engineer friend is dead now so I can’t ask him.

There are plenty of smart engineers on here that can explain that loading scenario far better than I am.
 
Newbomb Turk said:
They don’t rotate. They wiggle for lack of a better term.

I had an engineering friend who was no car guy by a long way and when he saw needle bearings on a reciprocating shaft he was stunned.

Thats because the needles should be rolled but they don’t roll because the rocker doesn’t move in a circle. He said you almost never see needle bearing on a reciprocating shaft like that because the needles end up digging into the shaft.

He said Thats first year mechanical engineering school knowledge.
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I definitely agree about wearing into the shaft and thought about that after I posted.

It would just seem to me if the rocker travels far enough during lift that there is the possibility that the needles could get full rotation on the shaft. If that is the case then the needle bearing circumference will be utilized, however I’m not sure the back and forth is good for them.
 

I have customers running BBM with Indy heads and HS rockers using springs quite a bit heavier than what EA would need for his SB.
Full time oiling with one .050-.060” restrictor per side.

These are combos that have been run for years with no pushrod cup or adjuster screw wear issues.

In my mind, it’s a non-issue………that I wouldn’t worry about solving unless it became an issue.

“If” I felt compelled to proactively address it, I’d just add pushrod oiling to the rocker gear, and run an even smaller restrictor to the heads.

If EA uses BAM lifters, those have edge-orifice oiling for the pushrods, so that would be fairly restricted anyway.
 
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As for the needle bearing rotation when the rockers have lash…….
I think of it as when the rocker is closing and the motion stops abruptly, the needle bearings have some momentum……..and since there is no longer any load on them while the rocker is no longer in contact with the valve, they continue to move some.
It would hardly need to move at all to have it so the needles are continuing go round n round.
 
Here's one way to do the math. There are others.

Each needle bearing roller is about 0.090" diameter, so the distance around the needle (circumference) is pi x diameter, so 3.14159 x 0.090" = 0.283". The distance around the rocker shaft is 3.14159 x 0.873" = 2.743". So to make 1 full revolution a needle would need to travel 0.283/2.743 = 10.3% of circumference of the shaft. 10.3% of a complete 360 degree rotation is 37 degrees. So if the rocker arm swept 37 the needle would make a complete rotation. For the lift I am running the rocker will make about a 26 degree oscillation. So, not a complete rotation of the needle.

If each needle only rotated a few thousands of an inch or only a fraction of a degree then only part of the bearing races and only part of the rocker shaft would ever get loaded. That could be problematic. With a 26 degree oscillation the entire bearing surface of the race and the entire rocker shaft (the bottom portions at least) will see load. I don't see a problem.

But as PRH mentioned above it's not really an issue anyway if the bearing continues to rotate when unloaded due to momentum.
 
PRH said:
As for the needle bearing rotation when the rockers have lash…….
I think of it as when the rocker is closing and the motion stops abruptly, the needle bearings have some momentum……..and since there is no longer any load on them while the rocker is no longer in contact with the valve, they continue to move some.
It would hardly need to move at all to have it so the needles are continuing go round n round.
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Little tips/observations like this are golden. This never occurred to me. Thanks.
 
I won't use needle brg rockers again.
Replaceable bushings, I like HS.
Seen rocker shafts brinelled like a worn out u-joint.
Needles turned to particles .

www.linearmotiontips.com

Brinelling and Why Bearings Fail

Brinelling is one of the more common causes of bearing failure. Here's a look at how to detect it and prevent it.
www.linearmotiontips.com www.linearmotiontips.com
 
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One thing I think a lot of people don’t really grasp is…….race car type parts……..don’t last forever.
Especially valvetrain parts.

They’re often more of a “consumable” item than some realize.
 
Inertia said:
I won't use needle brg rockers again.
Replaceable bushings, I like HS.
Seen rocker shafts brinelled like a worn out u-joint.
Needles turned to particles .

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Great description of the damage I wanted to say I'd happen seen too many times on Sprint Car engines in the early 80s. You could see where needles had been moving back and forth gouging the shaft & the needles had turned to powder.
When I first saw high performance bushed ones, I couldn't believe how many years it took to bring them out!
 
When I used up the life in the valvespring and started to see rocker bearing problems in my Jesels that's exactly what happened. The needle punctured an section of the cage and came apart.
 
For what it's worth, I'm presently building a LA 408 with HS 1.6 roller rockers, Comp Cams solid roller cam, solid roller lifters with oil band, and Trick Flow 190 heads. Contacted HS about oiling requirements. We discussed the two methods, oiling through rockers, and oiling through pushrods. We came to the conclusion the best option would be main oiling through the pushrods, and putting a restrictor in the head, under the rocker shaft pedestal to oil rockers. I tapped the pedestal hole out, and inserted a 10-24 brass setscrew with an .040 hole to start with. I'm using the Melling HV oil pump too.
I did the restrictor under the pedestal so it could be changed out without pulling heads. One thing I noticed between the Trick Flow and Edelbrock heads, is there is a step down in oil passage size on the bottom of the Trick Flow head. Drops to about 3/16" I believe. Have to double check. But it's a considerable step down.
Again, this decision was based on advice from HS tech support. To me, it makes sense. Any thoughts?
 
AZBoneFish said:
For what it's worth, I'm presently building a LA 408 with HS 1.6 roller rockers, Comp Cams solid roller cam, solid roller lifters with oil band, and Trick Flow 190 heads. Contacted HS about oiling requirements. We discussed the two methods, oiling through rockers, and oiling through pushrods. We came to the conclusion the best option would be main oiling through the pushrods, and putting a restrictor in the head, under the rocker shaft pedestal to oil rockers. I tapped the pedestal hole out, and inserted a 10-24 brass setscrew with an .040 hole to start with. I'm using the Melling HV oil pump too.
I did the restrictor under the pedestal so it could be changed out without pulling heads. One thing I noticed between the Trick Flow and Edelbrock heads, is there is a step down in oil passage size on the bottom of the Trick Flow head. Drops to about 3/16" I believe. Have to double check. But it's a considerable step down.
Again, this decision was based on advice from HS tech support. To me, it makes sense. Any thoughts?
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It will be interesting to get our FABO engine builders responses to this. It seems like a good approach to me and is the same advice I got from HS as well.

Was your 360 block a factory roller block or did you have it modified for roller lifters?
 
Earlie A said:
It will be interesting to get our FABO engine builders responses to this. It seems like a good approach to me and is the same advice I got from HS as well.

Was your 360 block a factory roller block or did you have it modified for roller lifters?
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My block is a 1972, non roller. Did a little grinding to get the lifters to go in the bore. Truth be told, I originally ordered lifters for factory shaft oiling, without the oil band. They are shaped different in the link bar section. After they got here, I saw I actually grinded more than I needed to. No harm, no foul.
 
AZBoneFish said:
My block is a 1972, non roller. Did a little grinding to get the lifters to go in the bore. Truth be told, I originally ordered lifters for factory shaft oiling, without the oil band. They are shaped different in the link bar section. After they got here, I saw I actually grinded more than I needed to. No harm, no foul.
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What's the lobe lift on the cam?
 
I run bushed rockers and bushed solid roller lifters from now on. One of the engines I put together for a drag week type deal ate a needle bearing solid roller lifter and the damage to the engine was “all encompassing” to say the least. Never again. On my personal W2 headed magnum I run bushed crane gold rockers with full time oiling to the shafts with .030 (if I remember correctly) restrictors in each line, as well as pushrod oiling from the hydraulic roller lifter. The pushrod oiling deadheads at the adjuster cup. I measured pressure at the shafts and on a drill with cold oil I had 80psi at the gauge and 80psi in the shaft. Never measured it hot or with the engine running.
 
AZBoneFish said:
For what it's worth, I'm presently building a LA 408 with HS 1.6 roller rockers, Comp Cams solid roller cam, solid roller lifters with oil band, and Trick Flow 190 heads. Contacted HS about oiling requirements. We discussed the two methods, oiling through rockers, and oiling through pushrods. We came to the conclusion the best option would be main oiling through the pushrods, and putting a restrictor in the head, under the rocker shaft pedestal to oil rockers. I tapped the pedestal hole out, and inserted a 10-24 brass setscrew with an .040 hole to start with. I'm using the Melling HV oil pump too.
I did the restrictor under the pedestal so it could be changed out without pulling heads. One thing I noticed between the Trick Flow and Edelbrock heads, is there is a step down in oil passage size on the bottom of the Trick Flow head. Drops to about 3/16" I believe. Have to double check. But it's a considerable step down.
Again, this decision was based on advice from HS tech support. To me, it makes sense. Any thoughts?
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That always sounds good but the oil leak at the lifters is real. I’ve never seen the benefit of pushrod oiling over factory oiling. Use one or the other.

Just my .02
 
TT5.9mag said:
I run bushed rockers and bushed solid roller lifters from now on. One of the engines I put together for a drag week type deal ate a needle bearing solid roller lifter and the damage to the engine was “all encompassing” to say the least. Never again. On my personal W2 headed magnum I run bushed crane gold rockers with full time oiling to the shafts with .030 (if I remember correctly) restrictors in each line, as well as pushrod oiling from the hydraulic roller lifter. The pushrod oiling deadheads at the adjuster cup. I measured pressure at the shafts and on a drill with cold oil I had 80psi at the gauge and 80psi in the shaft. Never measured it hot or with the engine running.
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Do you mind sharing the manufacturer of the failed roller rocker? And an approximate date/year?
 
Earlie A said:
Do you mind sharing the manufacturer of the failed roller rocker? And an approximate date/year?
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It was failed lifter, a cam/lifter set from cam motion which I believe came with a morel lifter. I could be wrong. Circa 2016.
 
What are probably the most common aftermarket rockers(not for mopars) are stud mounted needle bearing rockers………and nearly all(?) of those have no oil pressure at the bearing.

Just think of how many millions of those are in service.
 
If a rocker shaft was fully shimmed and the pedestals were machined to give support to the entire circumference of the shim, how would the needles escape? There would have to be a complete rocker arm failure (destruction) for needles to escape, would there not?

Trick Flow is the only SBM head (that I have) with nice, square shoulders on the pedestals. These would give nice support to the shims and needle bearing end seals. Factory heads and the Edelbrock style heads are as cast/not square, so I could see a needle escaping from the end on those heads.
 
Factory heads and the Edelbrock style heads are as cast/not square, so I could see a needle escaping from the end on those heads.
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You mean……..after it wears through the cage?

And aluminum rockers usually have steel shim between the rocker body and the hold down clamp(so a failed needle would need to get out past that too).

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PRH said:
You mean……..after it wears through the cage?

And aluminum rockers usually have steel shim between the rocker body and the hold down clamp(so a failed needle would need to get out past that too).
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Yes, the needle would have to get through the steel end seal/cage and through the steel shim to escape. If the shim were not supported by the pedestal then the shim could be pushed out of the way I suppose.

I'm just trying to understand/find the real facts. If a properly hardened and ground shaft is used and if a good needle bearing is used (like INA, USA made) and if the rocker manufacturer is using the highest quality aluminum or steel for the rocker body, do the needle bearings fail?

One failure by Brand X's needle bearing could ruin the reputation of the needle bearing rocker for all companies on a forum like this. Or what if a needle bearing is used on a non-hardened shaft like a factory Mopar shaft or a Chinese shaft. That might result in a failure, especially if an inferior shaft is subjected to high spring pressures and high rocker ratios. A needle bearing is not going to like a flexing shaft.

Kind of surprising that the best names in the rocker industry are using needle bearings if they are so prone to failure.

In their catalog, T&D does mention that bushings are available as an option for situations where contamination is the norm, like dirt racing.
 
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