what do roller rockers do ?
what do roller rockers do ?
they increase the valve lift and therefore increase the amount of air into ur engine....
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To put it very simply, roller rockers reduce friction and therefore save horsepower. They do this by rocking on needle roller bearings rather than the simple metal against metal pressed steel type. They may also be machined out of lighter, stronger alloys.
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Roller rockers may be ordered with a different fulcrum to enable more lift although that is a secondary purpose (but very useful....)Originally Posted by rufus
They can be roller rockers with roller tips as well. decreases friction against the tip of the valve.
cool, 4 replys and 4 different meanings lol
Rollin Rollin Rollin
they just open the valves if u get ones with a higer ratio they open valves more
Did we miss a couple of reasons
Roller tip = less sideload on valve stems (The main reason for use) = allows higher speed operation (Bigger cam) and less wear on the valves
Roller tip and fulcrum = less oil required for lube = better oil controll (Less oil draining back = more oil in the sump)
Less draining back? More in the sump? sounds cool, but how are you going to tell your oil to stay in the sump?
Posting aimlessly ..
Searching for more HP
has anybody fitted them and dyno tested the results?
i was thinking bout getting some for mine but had someone tell me he got 1rwkw out of his vx after fitting them.
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I would expect it is like any performance mods. You need to do it as part of a complete package, and then retune it to extract the POTENTIAL extra power/torque it may provide.
they reduce friction between the valves and reduce wear and tear and you dont have to be adjusting tappets
You dont have to adjust your valve lash even if you fit r/r to your commodore unless you have solid lifters. the beauty of hydraulic followers
The answer ? less friction and less weight being an alloy body component = more HP, but HP can be gained in many other places, never seen roller rockers without roller tips, different brands have different size roller tips, having them too small and using XXOS Isky double valve springs will wear a hollow into the valve stem very quickly.
With old red motors you can add roller tappets as well for very lumpy cams + 45/95 or more, idle at 2,000.
The solution is easy, how fast do you want to go ? fast = $$$
I was a petrol head once many years ago 110 mph in 2nd from a Celica 5 speed box ain't too bad but with 3 X 2" SU's your looking at around 8 -10 mpg driving slowly, drop that to 5 if a heavy foot.
Broke every part of the running gear, clutch centre, axles, uni's, tailshaft, planetary diff gears, just to name a few, the good old days.
now choppin the VZ
remember there is no such thing as free power. I assume new flash roller rockers will open up the top end while reducing low end torque.
roller rockers shouldnt lose you any power whatsoever. if they do, something is definitely wrong. the ecotec v6 has roller rockers stock, but lacks the roller tips of some aftermarket brands.
True but the V6 has roller tappets, not rockers, but with so many different sections of the internal combustion engine where HP can be increased one should not confuse adding HP such as using larger cams lighter flywheels, lighter pistons, balancing the entire engine or adding items like a blower or a turbo.
Much HP is simply not added but regained or let free and makes the engine produce what HP it's possible of making right off the production line, things like extractors, roller top end gear, all make the engine run easier with less friction, the off shoot is regained HP not really added HP.
Sure roller rockers will add more RPM being lighter which will allow higher RPM and with much less friction the off shoot is more HP but they are used mainly when combined with very strong valve springs to stop tappet bounce, the springs I used on my old beast were, grey outers and white inner Isky gear, and the rubbing removed 50% of metal from several lobes of the rather lumpy cam in a matter of months.
The 3800 V6 allready has roller gear inside it, adding roller rockers may give a small amount of HP, but with good roller gear like "Crane" costing near $100 each it's not a cheap mod, all leverage of the rocker being the same as the stock components combine to add enough small amounts of HP to give a substantial HP gain after all the goodies are added.
When young I worked for a Sydney GMH dealer testing / pre delivery of new cars, some were total dogs while others that were exactly the same were 30%+ better without touching a single thing, so if buying a new car, drive every one on the lot, one WILL go better than the others.
EG a VB 5.0 lit V8 was flat out down hill at 110 mph while a lousy 1600 gemini 5 speed hatch back did 115 mph easy, drive em all, whoever bought that Gemini got a good car.
sounds like you have a fair bit of experience in the car game. correct me if i am wrong, but arent tappets and rockers one in the same? it is dead right what you say about not adding power, but allowing the engine to spin faster and harder, thus making more power. i think the bigger issue at the moment on the forum is high ratio roller rockers. there has been a lot of talk of them and rightly so as they do give a lot of the benefits of a cam change without the work.
OHV - OHC all make the diff, say an old OHV red motor that has conventional tappets, IE the bits that rub on the cam, they can be solid, hydraulic or roller tipped "as per the V6".
OHC eliminates the pushrods making the cam push directly on the rocker or "roller rocker" as the case may be, and in turn directly to the valve, simple stuff, less moving parts, more RPM and more HP.
Remove the oil filler from the rocker cover and you will see a std pressed steel GMH rocker.
The rocker ratio can be 1.5-1, 1.6-1, 1.7-1, depending on what engine it is, IMHO much more HP is possible with stock rocker leverage (which has less pressure on the fulcrum) and using a higher lift camshaft built for your own needs, as against a higher ratio rocker which is only just a cheap cam mod opening all valves a bit more and a bit quicker, changing the cam timing is a better way to more HP.
Eco maniac, no great amount of training, except for my first grey motor rebuild, simply grab a manual, pull it apart to find what makes it work and fix it, simple stuff for anyone with basic mechanical knowledge, "and a father in the trade helps" but having also raced motorcycles since age 14 I did have a tad amount of practice with engines and tuning.
These days of engines run by computers changes much, generally when they fail to start, get out and walk as it usually can't be fixed on the side of the road as an old red motor can.
Last edited by digisol; 30-10-2005 at 06:23 PM.
Yep agreed here. There is obviously more effort needed to push the rocker through a higher ratio. Resistance causes friction losses as well. Ideally a cam with a high lift onto the a stock ratio rocker will use less effort to push the valve down. Where a cam with stock lift onto a high ratio rocker will take more effort to push the valve down.
Some people believe it is good to reduce the amount of oil to the rocker if it is a full roller type (this is debateable) as its not needed.
This is done by the use of Oil Restrictive Pushrods. ( basically a smaller oil hole in the ends)
Tappets - come from the early days when all we had was solid lifters (cam followers) and the need to adjust the gap between the tapping (Tappets) rocker and the valve stem top.
Now will hydraulic lifters there is no tapping sound and people call the rockers just that.
Early rockers had a friction rubbing pivot and tip, with an adjusting screw over the pushrod or the valve stem end.
Later with hydraulic lifters they lost the adjuster and were adjusted by a set pivot height.
Then they got the roller pivot point with a friction rubbing tip (ecotec V6)
After market rockers come with roller pivot points and roller tips.
Manufactured from steel / stainless steel / alloys and aluminium.
Some aluminium roller rockers are actually heavier than the pressed steel O.E.M. ones over the valve stem area.
They can be adjustable or non adjustable, depending on requirements.
They can come in stock ratios or and higher than stock.
The use of roller tip rockers usually requires the use of heavier valve springs due to the reasons of, higher ratio use, higher revs beening used (causing valve float/bounce), and valve train harmonics from heavier rocker tips over the valve.
Last edited by OZ38; 30-10-2005 at 06:35 PM.
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Simple quick answer - Reduce HP robbing friction.
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