Educate me concerning rocker arms

I might have a reason to mess around with rocker arms in the future.

Stock, they have hydraulic lifters in the end that push down on the spring hat thingymabobber. On the other side, a curved metal pad that rides on the cam lobe. Big shaft mount. (oh baby.)

If i were to want to make a setup that would handle massive power and say.... 8000rpms+, what would i do? Figuring that this will necessitate a custom cam, do i want rollers? Are rollers awesome? How would i convert to "solid lifters" in this case? Just take up the difference in the custom arms?

What motor are we talking about?

8000+ rpms will require at least strong valve springs and a cam that makes power there. Solid roller lifters will help a lot in that effort too.

The solid roller lifters replace your existing hydraulic lifters. Depending on your block, you'll need something to retain the lifters (a spider or lifters that are linked together in pairs). After that, you'll need to check your pushrod length. Solid lifters will require frequent valve adjustments.

At this point I haven't even talked about rockers. You can go roller rockers as well.

In short, solid roller is awesome, but is spendy and requires regular work.

Rollers are awesome, and damn near necessary at 8000+rpm. Don't forget you need to add in some way to adjust lash when you delete the hydraulic lash adjusters.

One good way to adjust lash could be to run a bolt, basically, through the end of the rocker where the HLA use to be. I use HLA because that's what Mazda calls them on motors like the F2T.

In reply to Gimp:

Mazda F2T. I have the springs taken care of, and will be designing a cam to be welded.

I don't have pushrods. Shaft-mounted rockers. I'm kindof thinking it wouldn't be a super hard feat to have some roller rockers made to accomodate the stock shaft.

Solid roller is kindof what i'm reading i should be using. I'm just not sure exactly all the details on what i'd need to do. (Besides having them made, obviously.)

BTW, the correct/common term for the rockers in a SOHC engine is "sliding finger cam followers" not rocker.

Ah ok well... I need some of those that will hold up nicely.

With something like this......

I certainly hope the lifter isn't pushing down on the "spring hat". The lifter pushes on the valve stem tip.

If you really want to go roller then you'll likely need custom rocker arms (good luck) unless there's an OEM or similar roller rocker available that can be modded to fit. If you want go this route, price a billet cam at the same time. I wouldn't run a roller rocker on a welded core in that application.

I know you didn't ask, so I'll tell you what I would do. If I recall, you may very we'll be able to do a solid rocker conversion from an earlier 8V motor. I've done a few of these for different applications and think I looked at the 8/12V heads for the same reason and think the rockers swap over. I would do that if possible, and run a reasonable lift. Being a (again off the top of my head) high 1.75-1 rocker ratio, that shouldn't be a problem without welding. At 8000 RPM and under significant boost, the valve train won't likely be your biggest concern with this motor.

In reply to oldeskewltoy:

Yes! I want that!

In reply to Zomby Woof:

Yeah valve stem tip, sorry. Work was awful today and the brain was fuzzy.

I may have a contact that could help me out with custom arms. May.

Stock rocker ratio is 1.72, so you remembered right.

I have no idea where to find a billet cam... don't think blanks are even available.

This is somewhat a continuation of the previous thread concerning the destroked long rod motor, but thinking it would probably be easier to make stupid power keeping it a 2.2 and just cramming an enormous amount of boost into it. (That said... I do have an fe3 crank test fit into an f2 block right now.)

Sounds like you think i'm barking up the wrong tree for this. I'm all ears! 500hp has been done on stock cam, I was figuring going with a welded cam to avoid having to deal with the tolerance issues that come up with a ground cam.

Just a sanity check here, but before you commit to all this work, are you sure that the stock units are an issue? You are not the first to hot rod an F2T, and maybe your creativity, time, and budget would be better spent on solving something that's an actual problem.

Just sayin'

If somebody actually made 500 hp with that motor on a stock cam, he's either a genius, or an idiot, and possibly both.

What do roller rockers bring to the table, aside from excessive cost? Less friction, and the ability to run more profile. Neither are of much concern for a build like this, so I don't see the benefit. 8000 RPM shouldn't be high for a setup like yours (assuming a solid conversion), and adding a roller doesn't address the real problem, the possibility of breaking rocker arms because you have a 1.75-1 ratio, and probably too much spring. If it were me, I would investigate the solid rocker conversion from the earlier 8V solid motors. If that's not a possibility, I would convert your hyd. rockers to a solid setup by replacing the lifter with a threaded insert and using a lash adjusting screw from another application. I've done some of those conversions so if you decide to investigate that I can help.

the problem is the lifter is built into the tip of the rocker...

oldeskewltoy wrote: the problem is the lifter is built into the tip of the rocker...

I would still think you convert that to a threaded insert to basically get a solid lifter with valve lash adjustability. Similar to Honda rocker arms.

Again, are you sure the HLA is an issue?
I tend to avoid moving HLA because of the extra rotational MOI.
Unlike legacy 'hydraulic lifters' of American V-8 that could not reliably function at 8K RPM,
that particular HLA is used on a bunch of high falutin' high revvin' import sewing machine motors.

I'll bet that any threaded manual adjuster you retro-fit will have similar weight, so what exactly do you gain?

Spoolpigeon wrote: I would still think you convert that to a threaded insert to basically get a solid lifter with valve lash adjustability. Similar to Honda rocker arms.

That's exactly what we do.

erohslc wrote: Again, are you *sure* the HLA is an issue? I tend to avoid moving HLA because of the extra rotational MOI. Unlike legacy 'hydraulic lifters' of American V-8 that could not reliably function at 8K RPM, that particular HLA is used on a bunch of high falutin' high revvin' import sewing machine motors. I'll bet that any threaded manual adjuster you retro-fit will have similar weight, so what exactly do you gain?

High falutin' high revving motor? Sure... if we're talking about the same motor that struggles to rev much past 5000rpms in stock form.

Zomby Woof wrote: If somebody actually made 500 hp with that motor on a stock cam, he's either a genius, or an idiot, and possibly both. What do roller rockers bring to the table, aside from excessive cost? Less friction, and the ability to run more profile. Neither are of much concern for a build like this, so I don't see the benefit. 8000 RPM shouldn't be high for a setup like yours (assuming a solid conversion), and adding a roller doesn't address the real problem, the possibility of breaking rocker arms because you have a 1.75-1 ratio, and probably too much spring. If it were me, I would investigate the solid rocker conversion from the earlier 8V solid motors. If that's not a possibility, I would convert your hyd. rockers to a solid setup by replacing the lifter with a threaded insert and using a lash adjusting screw from another application. I've done some of those conversions so if you decide to investigate that I can help.

I'm looking into the previous motors to see what's up with that... I would have thought someone would have already done that if it were the "easy button" though.

I'm with you that breaking the arms is probably the biggest potential issue, but that's why i was looking at having custom ones made. One, for better and more efficient movement, but mainly for strength.

As for the guy making 500hp on one...

http://www.youtube.com/watch?v=HxF7a3LYr9M

He went back a few days later and leaned out the tune a little (super rich in this dyno) and made over 480whp. (And around 540ftlbs to the wheels)

As for spring... well, i run a dual spring setup with around 80lb seat pressure now. Due to the effect of boost vs. pressure on valves, i may have to consider going with even more spring if i end up doing what i'm thinking about.

I like the threaded insert solution, but i'm also not 100% sure that the HLAs would really be the problem here.