Lets Talk Rockers
Lets Talk Rockers What's good these days? I currently run Crane quicklift 1.7 rockers and to be honest, I don't trust them. They have been on the car for over 10 years and I've had (2) crack near the roller. I replaced the (2) bad ones but I'm worried the rest will fail. I use these with comp 918 beehives springs. My car is on spray now and my worst fear is losing an intake valve on spray and somehow the intake blows as a result. Going back to stock is probably the most straight forward move however, I have no stock components so I will need to source new rockers, push rods and all other associated hardware. So, what would you do? I know Texas speed makes these: https://www.texas-speed.com/p-7364-t...oller-tip.aspx. Anyone run these? Any other options out there worth considering?
On The Tree
Joined: Apr 2015
Posts: 115
Likes: 1
From: Ohio
I've been using stock rockers with Smith Brothers trunnion kit. Only been on short time but no issues. I'm running Cam Motion beehives on 799 heads. Kit went together very smoothly using the press tool from BTR.
TECH Fanatic
Joined: Sep 2005
Posts: 1,584
Likes: 23
From: NYC
The Chinese are saturating the US with knocked-off GM rocker arms which is probably why they fail. https://www.alibaba.com/showroom/gm-rocker-arm.html
Buy GM Performance rocker arms, then add CHE bushings and don't trust anyone offering to sell you GM rocker arms unless it's a GM Dealer like SDPC: https://www.gmperformancemotor.com/category/LS2132.html
Buy GM Performance rocker arms, then add CHE bushings and don't trust anyone offering to sell you GM rocker arms unless it's a GM Dealer like SDPC: https://www.gmperformancemotor.com/category/LS2132.html
The Chinese are saturating the US with knocked-off GM rocker arms which is probably why they fail. https://www.alibaba.com/showroom/gm-rocker-arm.html
Buy GM Performance rocker arms, then add CHE bushings and don't trust anyone offering to sell you GM rocker arms unless it's a GM Dealer like SDPC: https://www.gmperformancemotor.com/category/LS2132.html
Buy GM Performance rocker arms, then add CHE bushings and don't trust anyone offering to sell you GM rocker arms unless it's a GM Dealer like SDPC: https://www.gmperformancemotor.com/category/LS2132.html
In my industry, I have seen first hand the Chinese ripoff guys at trade shows taking photos of new products to knock off. Then only weeks later we see the Chinese version on the shelf for half of the price. I digress... I like this advise. Did Chevy never make a roller tip version of their LS rockers?
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Verdad Gallardo I am fairly committed to going back to factory rockers but I'm curious about these Yella Terra ultralight rockers. I assume that their intent is to stabilize the valve train at high RPM. Is there any value on a motor that only spins to 7K? Is there any additional power to be had in this area of the motor? Just poking around before making a final decision.
Teching In
Joined: Sep 2018
Posts: 23
Likes: 2
I am fairly committed to going back to factory rockers but I'm curious about these Yella Terra ultralight rockers. I assume that their intent is to stabilize the valve train at high RPM. Is there any value on a motor that only spins to 7K? Is there any additional power to be had in this area of the motor? Just poking around before making a final decision.
friction from lack of a roller shouldn’t be a big deal because you wouldn’t be running huge lift numbers with stock rockers anyhow.
I’d only replace the stock rockers entirely if I needed adjustable rockers. I’d only need adjustable if I were running a solid roller and I’d only run a solid roller at high lift and really high RPM setups.
My opinion is based on limited experience but lots of research so fwiw
On The Tree
Joined: Sep 2016
Posts: 103
Likes: 18
Roller tip rockers don't actually roll across the valve tip anyhow, so unless you're going with a valve lift that substantially higher than say .620, I wouldn't spend the money. As has been said, you'll be just fine with factory rockers with o good bushing upgrade, or.......ws6store has a new CAPTURED needle bearing rocker that seems decent (although I haven't used them, just researched them). Coming from the world of BBC's where I've buzzed heavy stainless 2.19 and 2.25 valves to 7000 millions of times, I can't fathom that one couldn't fire up an ls, lay a brick on the gas pedal, and head off to work with no fear of a failure. It's an extremely light valve train. Proper clearances, proper oiling, and a good spring for kinematic forces and you'll be just fine up around 7000 or so.
Roller tip rockers don't actually roll across the valve tip anyhow, so unless you're going with a valve lift that substantially higher than say .620, I wouldn't spend the money. As has been said, you'll be just fine with factory rockers with o good bushing upgrade, or.......ws6store has a new CAPTURED needle bearing rocker that seems decent (although I haven't used them, just researched them). Coming from the world of BBC's where I've buzzed heavy stainless 2.19 and 2.25 valves to 7000 millions of times, I can't fathom that one couldn't fire up an ls, lay a brick on the gas pedal, and head off to work with no fear of a failure. It's an extremely light valve train. Proper clearances, proper oiling, and a good spring for kinematic forces and you'll be just fine up around 7000 or so.
On The Tree
Joined: Sep 2016
Posts: 103
Likes: 18
On a solid cam with lash in the system (cup teams), the rollers may change position during the lash cycle........but on a constantly loaded hydraulic system, they assuredly don't roll. They slide. Exactly the same as a non roller tip. The 8 hp comes from the exponentially less side loading of the valve against the valve guides. And in the OP's situation, I'd be inclined to think that 8 hp (if even that) isn't really worth the several hundred dollars cost of swapping to them. If one already has them, by all means, use them. If not, in his situation, the very minimal benefit doesn't outweigh the cost.
TECH Senior Member
Joined: Jun 2016
Posts: 22,308
Likes: 3,624
From: Central Cal.
On a solid cam with lash in the system (cup teams), the rollers may change position during the lash cycle........but on a constantly loaded hydraulic system, they assuredly don't roll. They slide. Exactly the same as a non roller tip. The 8 hp comes from the exponentially less side loading of the valve against the valve guides. And in the OP's situation, I'd be inclined to think that 8 hp (if even that) isn't really worth the several hundred dollars cost of swapping to them. If one already has them, by all means, use them. If not, in his situation, the very minimal benefit doesn't outweigh the cost.
On The Tree
Joined: Sep 2016
Posts: 103
Likes: 18
think of it this way, by using a much smaller curvature of radius of the wheel tip (.300 radius), its the equivalent of pushing downward on the valve tip with a razor blade. That tends to push more "straight down" on the valve than does the huge (in comparison) curvature of radius of the factory rocker (maybe a 4" radius?) with its much larger footprint on top of the valve tip. The much larger footprint will tend to push more sideways into the valve guide. The much smaller footprint will tend to push more straight down (while still pushing a little sideways, but not nearly as much). Just like a solid setup, the tip will change position some while the lifter is just coming off the base circle and force is low (which is what keeps it round and concentric), but also just like a solid setup, shortly after the base circle, when the force raises exponentially, the "roller" no longer rolls. It slides. Exactly the same as a factory rocker.
On The Tree
Joined: Sep 2016
Posts: 103
Likes: 18
Look at a wipe pattern of a roller rocker compared to a factory rocker, it's much more narrow. This is because the wheel moves much less distance across the valve tip than the stamped/cast factory rockers. That smaller amount of motion (because of the smaller footprint) creates less side loading. I'm certainly not implying that there's no benefit to using roller tip rockers, just that in the OP's case, I wouldn't think the benefits would outweigh the cost of a complete upgrade. When you're not straying too awful far from stock, and the factory shaft rocker system will run to 7000 all day long (barring the non-captured fulcrum needle issues) I don't see a point in spending money just to say you have full roller rockers, because really...........you don't. They still slide.
I have the latest version of the YT rockers on the LS1 in my C5 Vette.
The only reason being the AFR heads with bronze guides.
YT has been through several design iterations due to breakage. I had the earlier design and lost a couple, not a pretty picture.
At any rate, this latest version is notably beefier than the earlier version, not so sure they are still “Ultra Light”.
i just pulled these rockers yesterday as I am in the process of replacing the 5.7 with a 6.2 and will be using these heads.
After reading the discussion here that the tips don’t roll, I looked at mine with a microscope. I expected to see an area on the roller tip that did all the work given the claim they don’t roll. 20k mikes, many 1/4 mile passes btw.
I don’t see any evidence that they are sliding as opposed to rolling.
Springs are PAC from AFR and are 425lb open @ .600” lift.
Just my observation.
Ron
The only reason being the AFR heads with bronze guides.
YT has been through several design iterations due to breakage. I had the earlier design and lost a couple, not a pretty picture.
At any rate, this latest version is notably beefier than the earlier version, not so sure they are still “Ultra Light”.
i just pulled these rockers yesterday as I am in the process of replacing the 5.7 with a 6.2 and will be using these heads.
After reading the discussion here that the tips don’t roll, I looked at mine with a microscope. I expected to see an area on the roller tip that did all the work given the claim they don’t roll. 20k mikes, many 1/4 mile passes btw.
I don’t see any evidence that they are sliding as opposed to rolling.
Springs are PAC from AFR and are 425lb open @ .600” lift.
Just my observation.
Ron
I've read there's an increase in power, at least in part, with roller tips because the factory rocker.... for lack of better words.. loses lift as it goes through the lift cycle/passes across the pad, where the roller rocker maintains the lift of the cam, essentially bumping the lift a tiny amount. I'm low on sleep, I can't think of the wording used to describe it.
On The Tree
Joined: Sep 2016
Posts: 103
Likes: 18
No rocker has a linear ratio. This is because the tip of the rocker moves in an arc (with the fulcrum as its center point), while the tip of the valve simply moves up and down vertically. A 1.7 rocker (or whatever said rocker may be) is only 1.7 ratio in a very narrow window (usually around mid-lift and several thou to either side of it). Aftermarket roller tipped rockers gain a few hp (if the actually do, never take magazine articles as gospel) because the ratio is usually a little higher than what's advertised. "1.5" may actually be 1.7. They can get away with that because at some point in the lift curve it is assuredly 1.5. And 1.4. And 1.3. Even the OP's current rockers, the crane "quick lift" rockers gain their "quick lift" by designing the rocker such that the ratio is much higher early in the lift curve, then tapers off quicker towards mid-lift. Using them (and whether or not they will gain anything) depends on whether or not the engine wants a quicker lift curve, as one can easily overshoot the port. It's one of those situations where if the engine gained power, it likely had the wrong cam in the first place. But all rocker ratios, by nature, are non-linear. No 1.7 rocker is 1.7 throughout the entire lift curve.