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Roller rockers useless?

vxcalais_01

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RR's increase the lift of the values, so they open more and allow more gases in/out more freely. Durations are unchanged with RR's though, this is where a cam comes into it's own.

Rockers affect duration as well it has to, theres no way the valve can only slap up and down at that point of lift, it has to ride along the duration curvature as well if you know what i mean. But its not as much as what can be designed into a cam. High ratio rockers and cam are the best, as both have strengths that the other other hasn't.
 

Immortality

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Rockers affect duration as well it has to, theres no way the valve can only slap up and down at that point of lift, it has to ride along the duration curvature as well if you know what i mean. But its not as much as what can be designed into a cam. High ratio rockers and cam are the best, as both have strengths that the other other hasn't.

unfortunately no. rockers change the lift ratio only. they do not change when the valve lifts off the seat and when it is put down. with higher ratio rockers the valve just lifts faster to a higher total lift figure and then closes faster. basically it lets the cylinder breathe better sooner then with the stock rocker.
 

one_and_only2004

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**** i was told to go to chip torque $800 later for a memcal installed

That's because you have a VX - no memcal to just swap out in that computer.

Rockers are alright, but honestly they hold nothing to a cam. I wouldn't be making the power I do now with just a set of rockers.

As for chiptorque - I couldn't recommend them enough. All I've had is good help and decent gains from dealing with them
 

Cashaz

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Food for thought, this was a discussion between myself and Mace (Steve)

High ratio 1.9:1 (inc pushrod) and 1.9:8 does, I understand there is a specification difference, but I need a actual explanation what difference it makes in pro's and con's. (more fuel consumption, risk of blowing something, greater wear and tear to motor )", I understand giving me the Cons is actually not such a good sales technique, but honesty is what secures sales, (for me anyways).”

Great minds think alike I personally strive to be transparent about our products to enthusiasts, based on their needs/requirements, such that we can insure that they get what they’re after. I’m more then happy to answer questions, if I’m asked (I’m no mind reader LOL!).

The pros with rockers is that they offer quick and easy genuine bolt on gains, with minimal impact on fuel economy (depending on how it’s driven). The cons well there really isn’t any with the exception of tired valve springs, (on cars which have travelled a fair few k’s), may cause the valves to float in rare instances. If not treated (replaced) will eventually fail.

“Basically I want to know what rockers can do for the car, and what the ratio's do differently, also how does it act with your 10psi pulley system and your Int Cooler setup.”

As mentioned before, they allow the engine to breath much better much easier. In the case on an L67 with a 10psi (3.4”) pulley I would stick with the 1.9:1 ratio rockers, if you plan on running even more boost with an intercooler then I would go the 1.98:1’s
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Just thought, seeing it has been covered before
 

MACE

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Been meaning to add to this thread for a while now just never gotten around to contributing to it LOL. Fortunately people have been able to really help each other in this thread with little input from myself but will contribute to the following :D

I also priced how much it would cost to fix my bloody annoying tapets or lifters, whichever one is making that horrible noise and he said it's useless because there's not much point putting in new lifters and keeping an old cam. Might as well get a reconditioned ecotec?
What exactly do the roller rockers do?

You’ll find that if you run longer pushrods or linish/machine down the pedestals then it will most likely cure a lazy lifter

RR's increase the lift of the values, so they open more and allow more gases in/out more freely. Durations are unchanged with RR's though, this is where a cam comes into it's own.

Depends where the duration at 0.05” of lift is measured. For arguments sake if it’s measured at the valve then there will certainly be a measureable difference in duration

Stage 3 crow isn't exactly spastic. Frankly its a starter point IMO.

It depends on the application/requirements. Sadly there is no “one cam fits all”

**** i was told to go to chip torque $800 later for a memcal installed

I wouldn't touch chiptorque with a 10ft barge poll with a rubber on the end. Just me though.

Chiptorque are excellent at what they do and have very clever people on board and are one of the very few companies around that can reprogram the factory VX/VY V6 computers. They’re pricy though :(

That's because you have a VX - no memcal to just swap out in that computer.

Rockers are alright, but honestly they hold nothing to a cam. I wouldn't be making the power I do now with just a set of rockers.

As for chiptorque - I couldn't recommend them enough. All I've had is good help and decent gains from dealing with them

Selecting the right cam for the application will certainly work better then a set of rockers. However I just want to stress that everyone’s applications and budgets are different, of which it’s very important that people get clear early on as to what they’re after when they start modding their rides :)
 

a1k3m1

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and rockers are easy to put in, coz even an idiot like me can do it lol
 

Tsunamix

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Couple of quick pointers

Roller Rockers are a durability product. All they are is a standard rocker, with a roller replacing the contact pad between Valve stem and Rocker itself. This reduces friction at the top of the valve stem, reduces minute angle forces applied to top of valve stem. Both these things together improve high rev durability.

High ratio rockers have the contact point between the rocker and pushrod moved out so that a greater movement of valve is made with the same pushrod movement. The standard ecotec rocker ratios is about 1.6 or 1.65 from memory. This greater movement of the valve is called valve lift. I think 1.98 ratio rockers translates as about .52" lift max. This is where the major performance gain comes from when fitting high ratio rockers.

High Ratio ROLLER Rockers combine both. MACE's high ratio rockers aren't roller rockers - at least not the 1.98's I got. I Think he can sell you crow high ratio roller rockers though.

When you increase the rocker ratio, there is always a small increase in duration added. It's not much - 3/10's of stuff all, but it's because the valve effectively seals just before it comes off the ramp on the cam profile. This point changes a little with the added lift, for maginally more duration.

If your not planning on spinning your ecotech passed 6500 rpm, use MACE high ratio rockers. Get some Beehive springs to limit valve float as well. The standard springs float at around 6100RPM on engines over about 100K KM. By all means get a cam as well, but don't get a pre made stage anything cam, because they are usually ground to a spec where the cam controls lift and not the rocker. Having the cam add lift, and the the rocker add lift will probably result in spring bind / piston crowns punched in by valves with massivley excessive lift.

I'd personally crab a cam tech cam, ground to crow stage 3 with factory lift figures for a NA motor. When going forced, a Crow stage 2 with less valve overlap is a better profile. You don't want the exhaust valve opening while the inlet is open with FI or all your compression drops out of the exhaust. Big overlap is common in naturally aspirated race engines to aid intake scavenging, which is not need in forced systems.
 

MACE

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Just to summise as could go on the topic for day as have done so over the years.

Our rockers are based of the factory items which are roller rocker as they have a rolling element bearing in the truinion/pivot. They’re not roller tipped items, however from a bolt on performance application (without dealing with super heavy valve springs or highly aggressive cam profiles) it’s actually an advantages in a sense that the effective ratio increases with a non roller tipped item compared to that roller tipped item which will have a reduction in it’s effective ratio. From a bolt on performance perspective the higher the ratio the greater the performance no if’s no buts. It’s the reason people replace perfectly functioning reliable rockers with higher ratio items.

In regards to cam selection there are MANY grinds out there to suit these engines, of which if people don’t get clear early on with there experienced cam supplier (this is important as there aren’t too many around who know what work well for V6’s!) will end up with a slow fat pig of a car. I can’t stress this enough! I do feel bad when I get phone calls where people have been given bad advice and are wondering why they’re getting bad results due to poor component selection or cost cutting etc :(
 

vxcalais_01

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unfortunately no. rockers change the lift ratio only. they do not change when the valve lifts off the seat and when it is put down. with higher ratio rockers the valve just lifts faster to a higher total lift figure and then closes faster. basically it lets the cylinder breathe better sooner then with the stock rocker.

Higher ratio rockers and net cam duration • Speed Talk

There's a good graph on there to explain what i am talking about. It is not possible for it to lift higher and not be any change to the duration. In relation to the cam the valves are not lifting in a direct up and down movement at only one point, its across the whole lobe. I hope this explains what i am trying to say.


http://www.pontiacstreetperformance.com/psp/RockerArms.html

Above is another favorite i have read that explains this theory.
 
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