[max 93]

what is a good choice for roller rockers for a street car, stainless steel or aluminum ? What are the pros and cons for each ?

[chrisinestes]

I have the same question.

I'll add Full Roller or Roller Tip to the question, too.

Chris

[Old Man Taylor]

I put Crower full roller stainless steel rockers on my streetcar.

[Tim john]

Fan of Harland Sharp full roller aluminum rocker arms. Never had any issues with them. They have been a good investment for well over 25 years.

Tim john---

[chrisinestes]

I'm not trying to hijack, I swear! I just figure my questions will also help the OP and others that might stumble by this thread.

At what point are alumimum full roller rockers not strong enough? ie... horsepower, RPM, valve lift, spring pressure, length of time in use, etc...

Chris

[66bonne]

Originally Posted by Tim john

Fan of Harland Sharp full roller aluminum rocker arms. Never had any issues with them. They have been a good investment for well over 25 years.

Tim john---

Ditto. Have the same set of H-S full roller rockers on three different motors over 7 plus years. Umpteen thousands of street miles and a quadrabazillion strip passes.

Jim

[jamaca85]

the HS rockers would be a great choice, but if you dont want to spend the money, a set of comp cams roller tip rockers would work just fine for about half the price. i wouldnt use the off brand names. remember you get what you pay for...

[ANDYA]

My 70 GTO is a street only car with a stock type cam and the motor has Comp Cams roller tip rockers. Been in there for years with no problems.
My 69 Bird is a street performance car around 500hp with a solid lifter cam. On that motor I run Crower aluminum rockers.

[grivera]

If considering roller-tip rockers, keep in mind that they don't come with poly-pocks but full roller rockers usually do. This makes the price a bit closer between the two (if you intend to use poly-locks). I scored a new set of HS 1.5's from a fellow PY member for $200 shipped, so keep your eyes open if you have the time...

[1stGen Brawler]

I've got a set of rollers from Scorpion Racing on the Bird. Never missed a lick in the years they have been on there.

[HWYSTR455]

Originally Posted by Old Man Taylor

I put Crower full roller stainless steel rockers on my streetcar.

That's all I run too, but the PRW ones look to be about the same (Crower knock-offs) at a fraction of the cost. For the money for the PRW stainless, there's no reason to buy an aluminum anymore.

Aluminums are good, though they can wear out, and do flex some. At what point, not clear, but imagine it would be related to spring pressures. The stainless bodies pretty much never wear out, and are totally rebuildable. Also available separately, in the even one gets damaged. There are a number of options for the stainless too, like needle bearing tips, not a pin like the aluminums.

The stainless are also much smaller in size, where with some valve covers you have to clearance the aluminum bodies. Not sure about weight/mass, but I would guess they are lighter than the aluminums too.

.

[David Jones]

Originally Posted by Tim john

Fan of Harland Sharp full roller aluminum rocker arms. Never had any issues with them.
Tim john---

Same here........

[Steve C.]

Apparantly they all can flex some. Interesting tid bit from Hot Rod magazine...

In the May 2013 issue they recently tested 20 different rocker arms from all the popular manufactures in both aluminum and stainless. All of them were advertised as having a 1.6:1 ratio --- and exactly one of them multiplied the lobe lift of the cam to the valve accordingly. One in twenty. In fact they witnessed ratios as high as 1.668:1 when rotating the engine over with one rocker in place, and the rest were about 1.650:1. If 1.65 ratio rockers were tested we could expect similar results. One popular example, we often see the Harland Sharp 1.65 rocker arms being touted with 1.7-1.72:1 ratio.

It's not a design flaw, but it's there on purpose to make up for any deflection present in the body of the rocker arm and the pushrod, as both flex under the load of the valvespring, harmonics, and engine temperatures.

Valvetrain deflection is a real problem, and they have witnessed as much as 0.05 inch in lost lift at the valve due to stiff valvesprings flexing the body at the rocker arm pushrod. That was just measuring lift with the engine on a stand. Imagine how much more lift is lost when the engine rpm reaches the stratosphere. Thus Rocker-arm manufactures sometimes combat this problem by designing more ratio into the body than what's stamped on it.

In an engine applicatrion, aluminium's lifespan is significantly shorter than steel or stainless steel due to the fact that it fatigues faster during each heating and cooling cycle. Steel's fatigue limit is approximatly half of its tensile strength, while aluminium's fatigue limit is about 40 percent of it's tensile strength. On a street car I wouldn't think many would lose much sleep over it.


.

[Old Man Taylor]

I put my SS rockers on in 1982. There were not as many choices for parts then. I used SS because I wanted them to last as long as possible. Lift is 0.600".

[chrisinestes]

Thanks for all the input. I'll most likely go with steel full rollers.

Chris

[grivera]

Originally Posted by Steve C.

Apparantly they all can flex some. Interesting tid bit from Hot Rod magazine...

In the May 2013 issue they recently tested 20 different rocker arms from all the popular manufactures in both aluminum and stainless. All of them were advertised as having a 1.6:1 ratio --- and exactly one of them multiplied the lobe lift of the cam to the valve accordingly. One in twenty. In fact they witnessed ratios as high as 1.668:1 when rotating the engine over with one rocker in place, and the rest were about 1.650:1. If 1.65 ratio rockers were tested we could expect similar results. One popular example, we often see the Harland Sharp 1.65 rocker arms being touted with 1.7-1.72:1 ratio.

It's not a design flaw, but it's there on purpose to make up for any deflection present in the body of the rocker arm and the pushrod, as both flex under the load of the valvespring, harmonics, and engine temperatures.

Valvetrain deflection is a real problem, and they have witnessed as much as 0.05 inch in lost lift at the valve due to stiff valvesprings flexing the body at the rocker arm pushrod. That was just measuring lift with the engine on a stand. Imagine how much more lift is lost when the engine rpm reaches the stratosphere. Thus Rocker-arm manufactures sometimes combat this problem by designing more ratio into the body than what's stamped on it.

In an engine applicatrion, aluminium's lifespan is significantly shorter than steel or stainless steel due to the fact that it fatigues faster during each heating and cooling cycle. Steel's fatigue limit is approximatly half of its tensile strength, while aluminium's fatigue limit is about 40 percent of it's tensile strength. On a street car I wouldn't think many would lose much sleep over it.


.

Great info Steve, tx

[max 93]

So it sounds like it doesn't make much difference for a street car.

[Don 79 TA]

i've had Crower Aluminums since the 90s
no problems at all
using 1.7 crower SS now
while they are heavier, that weight seems to be centered if you will, so don't think it's that big of a deal

as far as clearance, no issue using the 1.7 or 1.65

Skip's used offset BBC crowers too, so if you need more lift, could be a good option

[HWYSTR455]

Originally Posted by max 93

So it sounds like it doesn't make much difference for a street car.

Depends on the street car really. These days, some street cars rival race cars. My one friend jokes about how my street cars smoke half the race cars out there, at the tracks around here anyway. (his comments are based on the build, not particularly 1/4 times)

.

[Mechanic No. 4]

Originally Posted by 1stGen Brawler

I've got a set of rollers from Scorpion Racing on the Bird. Never missed a lick in the years they have been on there.

X2 for Scorpion Racing. Put them next to a set of HS and you'll see the difference!!