I'm looking into doing some fairly easy and inexpensive mods. I'm planning on full exhaust and I'm considering aluminum roller rockers. I'm wondering if going with stock ratio 1.5 rockers will yield significant gains (they claim up to 15hp)? I'm also curious as to how much 1.6 rockers would upset the SD computer? Obviously if I can use 1.6's without a problem that'd be better, but I also know that the SD computer is kind of sensitive. Thanks for the help.

 

i doubt if you see or feel any real change with 1.5, maybe by going to 1.6 you might see a slight gain, but i doubt it'd make much differance.

 

I wish I owned stock in a Roller Rocker Arm Company.....

* Note to self:

 

Real rockers as opposed to stamped sheet metal ones will give you consistency from one cylinder to the next that you don't have now. They aren't good for a whole lot of HP, 15 HP is a bit optimistic to say the least, but your engine will run somewhat better.

Don't use aluminum on the street. They will break, guaranteed. Aluminum moving parts never last very long because of "fatigue", a specific failure mode which ferrous metals don't enjoy.

If you simply must spend money that way, get steel ones like the Comp 1300 series.


F-Bird: buy stock in a gear drive company, that's really useless and wasteful. at least roller rockers are an improvement over what comes there, whether economically sound or not.

 

" Ya, It's got a 4.10 gear drive"

Oh ya! almost forgot about the Gear Drives...LMFAO


A friend actually tried one of these on the dyno.... -40HP
All that noise is friction ... Hee Hee!


Thanks for the reminder

* Note to self:

 

Don't use aluminum on the street. They will break, guaranteed. Aluminum moving parts never last very long because of "fatigue", a specific failure mode which ferrous metals don't enjoy.

i don't believe that aluminum is ferrous. i believe that one of the main qualities of ferrous metals is that they are magnetic.

I could be wrong though.

but i do believe that RB83L69 is correct about the fatigue of the aluminum. but i am uncertain if the fatigue has a major roll in rockers.

 

i do remember saying an article in I think it was a summit cataloge about aluminum rockers, and how they last about 20-30k miles..

however forged steel rockers weigh about the same as aluminum and will last forever..

do a search on it

 

ace reread what rb said, he said aluminum wasn't ferrous, he just didn't say it in a direct way

 

If that was true about aluminum rockers, I would think the '96 Vette LT-4's would have been recalled? or have they already?

If memory serves, they use the crane golds.


Ron

 

They are only like the Crane Golds. They are actually different.
They have a shorter slot to strengthen the body.
They do not handle as much lift as a Crane gold because of this.
I read about some other design differences that improved their durability, but can't recall them now.

 

Alluminum RR's are supposed to have a life of about 30,000 miles from what Crane cams told me.

 

Good quality aluminum roller rockers will last 30K or more
(Crane or GM)
Cheapos (Proform, etc) you take your chances with.
Stainless or Chromoly (Comp, Crower) are probably the most durable, but they'll still need rebuilt (bearings) ebery now and then.
My 2 cents...
-Rich-

 

sorry about that, i guess i misread the post.

 

Replacing bearings is a whole lot less painful than buying new rockers because your old ones start breaking in half...

 

A cam is good. Roller lifters....yea, sure

Most important, buy stock in:
-Aggressive Auto Sticker/Emblem companies
-Companies that make and sell useless wings and spoilers
-Any company that makes wheels greater than 17 inches

Let them suport my 3rd Gen habit of trying to keep my car stock.

RB

 

slackett dont forget NAWS companies

or

get the equipment to be able to fill up those 10 lb bottles for the ricers. might be able to make money from that

 

I know that aluminum is much weaker than metal and that the alum. rockers arent supposed to last long but I am still waiting for a failure on my Crane gold non-self aligning 1.6s on my 93 T/A (which redlines at 6500 rpm) . I am presently at 60 + thousand miles with the rockers.
Perry

 

Aluminum is "metal." You mean "weaker than" steel.

 

The Crane "Gold" Rockers are the best aluminum rockers!
-Rich-

 

Well 'Perry93TransAm' you do know that your roller rockers aren't suppose to last but 20,000 miles !!! You better go out to that car right now, and tell them to break gosh dang it!!!

Ron

 

If one guy can have a skydiving accident at 10,000 feet and survive even though his parachute fails to open, doesn't that mean we all don't need parachutes when we skydive?

If aluminum rockers have lasted that long on your motor, you're lucky. That's not the norm, and not what should be expected. Enjoy your good fortune while it lasts!! Sometimes stock ones don't even make it that far.

 

I agree - A nasty sized cam can make short work of AL roller rockers.

Ron

 

I'm sorry I said metal instead of steel, My mind was thinking metal fatigue when I was writing. anywho, I have only been skydiving a few times and I'm just happy to still be standing...lol.By the way I'm using a cc 305 cam and hardened steel pushrods with the aluminum rockers. I brought forth my example too because I know its not normal but that we should also not wet our pants and run around like our hairs on fire because our aluminum rockers are rolling down to 19,999 miles. Sure I know some day they will break. I'm also the kind of guy that is always playing with stuff so I see them quite often...lol. Just a few months ago I broke a stud (CC 3/8ths screw in w/guideplates) So I changed all my studs to the ARP pros (like em) I also bent a pushrod in the process so I changed them out too (but missing your shift and 7000 rpms can do that, bend em that is). I examined each rocker thoroughly and cleaned each with solvent and reoiled them before I reinstalled them, They all showed minimal wear (except for that one that the stud broke on, the paint was scratched) but they look to me like that they are as good as the day I bought them in 1995.
Perry

 

You won't see the failure before it occurs. The problem is not wear. It's fatigue. The material will only withstand just so many work cycles before it simply snaps in half at the highest-stress point. That's why the FAA has rules that require all sorts of maitenance and inspection of airplane frames and powerplants (all made of aluminum of course) at regular intervals, and mandates that some parts be replaced whether they inspect good or not, because they fail suddenly without warning. Steel does not enjoy this particular failure mode, and stress damage can be detected much more reliably in it. And of course, steel is a far stronger material in the first place, and can often be made to have a higher strength-to-weight ratio than aluminum, especially for moving parts.

Aluminum rockers usually break right behind the roller tip. Someday you'll wake up, start your car, and it will run like crap out of the clear blue, even though it was perfect the time before; when it happens, it will be a rocker.

 

Be careful putting 1.6 rockers on stock springs. Even though they are steel they will fatigue too. The diff between Al and steel is that if you keep the stress low enough in steel it has an infinity cycle life where as Al no matter how low the stress and a cycle limit. Al is for racing only, or non load bearing items such as intakes, floor pans, tubs, etc.

To reply to your original question Al makes more power because you can run more cam at high RPM with less spring rate because the weight is so much less.

 

Thanks for the info everyone.