What do Roller Rockers Accomplish?

I've heard and seen everyone use them, but what do they really do for you? Cut down on friction? Do they add HP? I couldn't see any way they could with just bolting them on.o No:

 

I see the advantages of roller rockers as:

• Generally more durable with a longer service life
• Advantage of various ratios available
• Can increase or decrease lift of same cam depending on rocker ratio
• Ensures cam specifications are applied in engine
• Able to compensate for machine work to the head and block
• Able to compensate for different head gasket thickness
• Eliminates necessity of adjustable pushrods (relatively weaker)
• Allows for consistent preload on lifters and adjustment for maximum performance
• Allows greater lift and spring pressure for bigger or aggressive cams
• Less chance of catastrophic rocker failure (especially in performance applications)
• Will allow the use of solid or roller camshaft grinds and lifters (oh yaaaaa!)
• Less friction and wear on the rest of the valvetrain

Cheryl

 

Thanks Cheryl and Larry...

:TU:

 

Roller rockers provide a couple of benefits, assuming you are using the same ratio as either stamped steel or iron rockers. Typically, rollers are lighter in weight and have measurable friction savings in the valve train. This reduced weight allows more controlled valve action (assuming the use of the same springs) and can allow for either bigger valves, lighter springs or even a bit more radical cam timing. The reduced friction translates to higher HP at the flywheel.
Think about it this way, would you rather drag 500 lbs of dead weight across concrete, or would you prefer to put wheels on that 500 lbs? Not an exact comparison, but close enough for this example.
The question of whether or not rollers are stronger than stock rockers is fairly easily answered when discussing typical stamped steel rockers as found in most SB Fords and Chevys, Olds engines and Pontiacs. Think of the rest of the valve train. If you have a fairly radical cam and the stiff springs required to control the valves using this radical cam, it's pretty tough to have the valves move. If you have stamped steel rockers, they can bend and flex if the wall thickness/rocker design isn't up to the effort and force required to move those stiff springs. The rollers are usually stiffer and, having less friction to move them due to the roller fulcrum and the rocker tip rolling across the valve tip rather than being forced to scrape across the valve stem, they flex much less than the stamped steel.
Another benefit of **quality** rollers is that they are more accurate in ratio in a set of 16 than stockers. The reason is better quality control. It's like assembling an engine with some pistons at .05" dech height, some at .03" and some at .07". If you do the math to see exactly what I am talking about it goes like this:

Actual cam lobe height: .350
Actual rocker ratio: 1.6
Valve lift: .560

If you have a set of rockers where the biggest ratio is actually 1.62 and the lowest is 1.58 the math goes like this:

Actual cam lobe height: .350
Actual rocker ratio: 1.62
Valve lift: .567

Actual rocker ratio: 1.58
Valve lift: .553

for a difference in lift of .014

Both rockers would be considered 1.6 ratio rockers. You get the same kind of variations with duration.

One thing our Buicks have going for them is the shaft mount rockers. Good motion control and a stiffer valve train. This assumes of course that one has good quality rocker shafts and bolts to hold them down with.

The question to actually answer is whether or not that reduced friction, ratio availability and valve clearance adjustability is something your engine really needs. If so, spend the bucks for a **quality** set of rollers. There is a lot of trash out there claiming to be "equal to so and so, but without the big cost". Remember, if it seems to good to be true, it probably is.:Smarty:
Phil

 

They really have the greatest advantage on high rpm motors.

 

I agree with Tom, I don't think they do much in a street engine. Sounds "cool" when bench racing though. Mike D.

 

Let's ask Mr. Tri-Shield (Mike)

Want to weigh in here? Are roller rockers 'worth it' for a street car? At what point would you recommend to a customer that they move up to full roller rockers?

I ask because even the OEM's are going to rollers, either cams/lifters or rockers on even the lowly Olds 307 that powers my daughter's Chev Caprice wagon.

Phil

 

I just put in a set this summer. Did not expect any HP gains but was able to make sure the preload on the lifters was correct. If/when I change cams will be an easy adjust.

 

Another thing they will accomplish is too drain your wallet. They cost like 600 or 700 dollars don't they?

 

TA's do. I would not have them except for getting a deal ($300) about the same as TA rebuilt set.