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B20 roller rockers?

hiperfauto said:
Don't all roller rockers pressure feed oil to the roller tip? I know the T&D rockers I have do yet they still seized. Does drip oiling work better?
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No, bbf just does drip, pushrod feed, into the bolt down cavity and a valley or chamfered hole leading to the tip. But no pressure fed oiling to the tip roller.

Some ( a lot from my research) of sbc, sb mopar run forced tip oiling, like you have pictured. This to me would be ideal if there were two jets, one to each side of the roller tip. But lots of extra effort for little advantage.
 
I know this is an old thread, but I’m building a b18 vintage race motor and am trying to fabricate a set of roller rockers. I’ve made some bushings and mocked up a pair of Buick v6 rockers on the Volvo shaft, but the rollers don’t align with the valve stems. What rockers have others used for a b18/b20? I don’t want to narrow the stock pedestals, but with the Buick rockers that’s my only option.
 
dxhall said:
I know this is an old thread, but I’m building a b18 vintage race motor and am trying to fabricate a set of roller rockers. I’ve made some bushings and mocked up a pair of Buick v6 rockers on the Volvo shaft, but the rollers don’t align with the valve stems. What rockers have others used for a b18/b20? I don’t want to narrow the stock pedestals, but with the Buick rockers that’s my only option.
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How far away are they? And what rockers did you end up with?

I’m currently working on a redesigned roller tip rocker set. New pedestals, and clean sheet arms using the stock shaft. Unfortunately, what I’m seeing is small geometry errors from one head to the next. Meaning there are subtle changes between each of the three heads I have as far as tip>valve stem sweeps.

Typically in a sbf-sbc, you’d adjust this via pivot height until the swing across the valve stem that is centered around half lift of the cam. With these engines, you really can’t do that. That’s what I’m trying to get a good idea about.
 
The misalignment with the Buicks is front-to-back, i.e., the roller is not centered on the valve stem by about .15 inch. If I narrow the pedestal, I could get it on center, but I’m concerned about flex in the shaft if I do that. I have not found any roller rockers with off-center rollers, which is what I need. There are many with off-center pushrod cups.
 
Mopar rollers are offset, and close to stock geometry between the pushrod seat and the pivot center. But depending on the installed spring heights and valve seat heights, the tip may not be in the optimal position.

With most springs in b18-20s you could mill the side of the rocker instead of the pedestals. But it may depend on how much meat there is available at the rocker pivot.
 
Back at this. I’ve got a prototype 1.65:1 that seems like it could work well. Going to be printing them this week to verify things. If all goes well, I’ll be moving to aluminum or printing them in stainless steel. Have to verify the costs first, but the design lends itself to either process pretty well.
 

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cwdodson88 said:
Back at this. I’ve got a prototype 1.65:1 that seems like it could work well. Going to be printing them this week to verify things. If all goes well, I’ll be moving to aluminum or printing them in stainless steel. Have to verify the costs first, but the design lends itself to either process pretty well.
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Not sure if for the print or not, but the tip spindle probably needs to be a lot larger in diameter.

I'll add in here, that 3d printing SS would be really neat but the design needs to have a lower polar moment of inertia than the aluminum rockers. Otherwise I'd make them from aluminum, as no one is using springs stiff enough to warrant the needed stiffness and valvetrain stability of a steel rocker. And by stiff valve springs, I'm talking like 300+lbs closed. Some of the newer NASCAR and pushrod race engines are using very slim steel rockers with low polar moments of inertia AND having a higher resonance frequency and stiffness over previous things. But that's for the when you're spending $250k+ developing a pushrod that works well at a specific race track.

One a few engines we're running a nice "mild" spring setup and seeing 7500/8k repeated beatings without the valvetrain getting upset. This is with an R cam, but it would work for more aggressive cams as well.
 
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cwdodson88 said:
Back at this. I’ve got a prototype 1.65:1 that seems like it could work well. Going to be printing them this week to verify things. If all goes well, I’ll be moving to aluminum or printing them in stainless steel. Have to verify the costs first, but the design lends itself to either process pretty well.
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culberro said:
Not sure if for the print or not, but the tip spindle probably needs to be a lot larger in diameter.
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The pin is .234” roller tip is .5”, section around pin increases from .150 at the bottom to .350” or so at the top.

the print variation is a bit different from the billet version due to material differences and weight.
 
cwdodson88 said:
The pin is .234” roller tip is .5”, section around pin increases from .150 at the bottom to .350” or so at the top.

the print variation is a bit different from the billet version due to material differences and weight.
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That should be OK. Using an off the shelf roller and needle setup or going with a bushing?

In the screen shot the hole looks to be ~3mm in diameter, and I've seen rockers made that way. Not ideal.
 
culberro said:
That should be OK. Using an off the shelf roller and needle setup or going with a bushing?

In the screen shot the hole looks to be ~3mm in diameter, and I've seen rockers made that way. Not ideal.
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Rather than run a needle, I’m sticking with stock bushings. To fold, this will allow staging the upgrade using the stock rocker shaft and stock bridges, or updating to the girdle bridge that I’m wrapping up now.

That screenshot is from an early tester… I thought it was the newest rev… but looks like it’s not. lol too many cad files, not enough coffee
 
cwdodson88 said:
Rather than run a needle, I’m sticking with stock bushings. To fold, this will allow staging the upgrade using the stock rocker shaft and stock bridges, or updating to the girdle bridge that I’m wrapping up now.

That screenshot is from an early tester… I thought it was the newest rev… but looks like it’s not. lol too many cad files, not enough coffee
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Trunnion bearings being bronze is a good move.

What about the roller tip? Needle or bushing? There’s been a big push to bushing as the bearing and pin material is all over the place from the usual suppliers. Also, less contact stress for the roller tip spindle/pin.
 
culberro said:
Trunnion bearings being bronze is a good move.

What about the roller tip? Needle or bushing? There’s been a big push to bushing as the bearing and pin material is all over the place from the usual suppliers. Also, less contact stress for the roller tip spindle/pin.
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Tip is going to be ground id/od bearing grade steel with hardened ground tool steel pins. Oil jets directly spraying the pin on each side. The beauty of 3d printing
 
Haven't seen them yet, but from my use, they weigh more than stock. YES they have advantages but weight is weight when you want to move it
 
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