rockers

[djswwg]

has anyone used PRW stainless rocker arm systems on their mopar? good or bad results? they look ok online but does any body know for sure? check 'em out at www.PRW-USA.com ..............djs

[pishta]

Those stainless look like an Ebay item that goes for 107.00 a set without shafts. I was considering them too, as I already have hardened shafts. Anyone else?

[cudabob496]

Seems stainless rockers would be very heavy!

[toad490]

Some, but not as much as you would think. Stainless is much stronger than ally so they use alot less material and they don't fatique/work harden like ally so are a much better choice for a street engine.

[cudabob496]

Originally Posted by toad490

Some, but not as much as you would think. Stainless is much stronger than ally so they use alot less material and they don't fatique/work harden like ally so are a much better choice for a street engine.

I would think a thicker aluminum rocker would be the way to go, due to weight savings. I think the Crane rockers I have are aluminum.

[340_GTS]

Often, thicker aluminum weighs about the same as thinner steel. Plus the steel is stiffer and will last a lot longer due to the material being stronger and more fatigue-resistant. But I absolutely would not buy $107 rocker arms! You do get what you pay for! Here is what Comp Cams says about their steel Pro Magnum rockers: "Lose the weight, keep the strength.
COMP Cams Pro Magnum shaft mount roller rocker arms combine the strength of 8650 chromemoly steel and the weight savings of aluminum rockers. COMP Cams took advantage of computer design to simulate the stresses that affect rockers under various operating loads. This allowed the engineers to lessen the rockers' mass at non-critical areas, and strengthen the areas that take the most punishment. The results are rocker arms that are strong where they need to be, and actually weigh 5 percent less at the valve than comparable aluminum rockers."

[cudabob496]

Good info, but at only a 5% weight savings, its probably more important
how they are designed, quality of workmanship, and how they behave at 7000 or 8000 rpm. A lot of times aluminum is preferred due to its ability to absord rapidly changing loads.

[340_GTS]

I was really just trying to illustrate that there was no reason a properly designed steel rocker had to weigh more than an aluminum one.

[toad490]

Originally Posted by cudabob496

Good info, but at only a 5% weight savings, its probably more important
how they are designed, quality of workmanship, and how they behave at 7000 or 8000 rpm. A lot of times aluminum is preferred due to its ability to absord rapidly changing loads.

May be true but I've never seen it brought up in regards to rockers, if it's true it comes at a price, there's a reason ally rods don't last as long as steel, R&R says my ally rods are good for 6500 miles, I sure wouldn't push ally rockers any further than that and high quality ally rockers are damn expensive. IMHO high quality steel are the best choice for a street/strip engine. I know if I could've got them for my Indy 440-1 heads I would've. Instead I got T&Ds and they set me back all most 2000 beaver bucks, that was with four extra rockes in case of breakage.

[pishta]

The new AL rods are supposed to be as good as steel with the better metalurgy for endurance, but that is a part that probably could stay steel, like a crank. They could make an AL one but I dont think it would be cost effective nor stand the punishment as AL rods are much bigger physically.

[toad490]

Originally Posted by pishta

The new AL rods are supposed to be as good as steel with the better metalurgy for endurance, but that is a part that probably could stay steel, like a crank. They could make an AL one but I dont think it would be cost effective nor stand the punishment as AL rods are much bigger physically.

Here's a artical on R&R Rods and still they say 6500 miles for rods when you talk to therm. My point was the same considerations apply to ally rockers.


http://www.productionmachining.com/a...component.aspx

[DartGT66]

Aluminum flexes more than steel, have to tkae that in to account when figuring out clearances, piston to valve, piston to head etc. Not necessarily always a good thing.

[pishta]

except with main caps. AL main caps seem to really save cranks in high HP situations. Seems they absorb lots of otherwise detrimental vibrations and shock loads to cranks. Guy was busting cranks so he went to AL caps and never broke one again. Must be doing something right.

[DartGT66]

True, we have used aluminum main caps with success too. And also rockers since ther5e isnät anything else to choose. If there were, I would propably use steel.