Hey Everyone.

Im torn on a decision at the moment.

I have listened to many opinions, and im trying to hear more.

What are your opinions of steel rockers vs. aluminum rockers.
What is your opinion of steel roller tip vs. Aluminum full roller?
What is your opinion of Stamped rockers vs. roller rockers? (fulcrums)

Thanks for the help!!!

Sheldon

 

The thing about opinions is everyone has one.

Kind of like something else everyone has. . .

Now, if you want facts. . .

 

Im hoping opinions are based on facts, and include facts

for pointing that out though

 

Aluminum fatigues - fact. It has a cyclic limit of roughly 10^8 cycles, due to it's FCC crystal structure, IIRC. Compared to an infinite life for BCC crystal structure, such as a ferrous based material like steel.
(Austinitic SS is FCC however... hmm...)

*fact* - If Aluminum is stressed to within .35 of it's yield strength, that will fatigue it. If it's thick enough that you're below .35 of it's yield strength in normal usage, it *may* not fatigue (as quickly). I doubt this is the case.

Aluminum rockers will wear out, and it's hard to say when. They are more expensive typically. They are thicker to make up for the lack of strength, which can kill the weight savings.

**opinion to follow **Make a note that comps steel (pro magnums I think?) are advertised as being the same weight as AL ones. hint nudge.

**opinion** I'd use a steel roller tip one if it were me. I'm running stamped roller tip ones from summit, $89 a set. My spring forces aren't high enough to really need a beefy full bodied style one, my springs may be deforming my stamped ones to the point that i'm not getting my full 1.6 ratio, but that's ok for me.

There, the facts I listed are based on mechanical engineering principals from a recent materials course I took. The opinions are pulled straight from my rear end

 

Pretty much what sonix said. To add to that you free up a few more horses with a full roller. The Com pro mags (Steel) will handle anything you can throw at them. Aluminum are recommended to be changed after 60k miles ( I read this when researching for my build, sorry I don't recall the book ). I used roller tip rockers for many years without any problems. I upgraded to full rollers because I had the cash and found a great deal on the Pro comp 1.6 ( 150 bucks ). Obviously stamped steel work fine for stock or moderately modified engines. My Z-71 has 175k on it and I have yet to remove the valve covers on it. She still runs like she did the day I bought it.

 

Comp Cams Pro Mags all the way. Spend the extra $$ for the better rocker. I've broken a Crane Gold rocker. I've done a lot of damage in the last few years but never hurt my Pro Mags. Now if price was no object, Jesel or T&D shaft rockers are far superior to any stud mounted rockers.

Stamped steel rockers are only required when you're building a stock rebuild street engine or racing in a class that doesn't allow a roller rocker. That's why there are performance stamped steel rockers. Factory rocker ratios can be all over the place. Aftermarket ones are all exact. For higher lift cams, they also provide long slot rockers so that the rocker doesn't bind on the stud.

For the added cost to buy a stamped steel roller tip rocker, spend the extra money to buy a full roller rocker. The majority of the friction in a rocker is at the fulcrum not at the tip.

 

Thanks for all the help everyone!

Ive Narrowed it down to 2 rockers:

Summit aluminum 1.6 Full Roller Rockers - $249 (narrow body, self aligning)
Comp Magnum 1.6 Roller Tip $191 (Narrow body, self aligning)

The summit ones include locks, and are quite beefy.

This engine will see another 30 000 - 40 000 miles of use, if that, before the motor is ripped out for a 383.
----------
Ok,

Ive narrowed it down to 2 rockers:

Summit 1.6 Aluinum Full Roller Rockers - $249 (Narrow body, self aligning)
Comp Magnum 1.6 Roller Tip Rockers - $191 (standard body, self aligning)

Based on the fact that this engine will see another 30 000 - 40 000miles of use before a 383 is put in, which would you reccoment?

Thanks,.

Sheldon

 

Summit Rockers:



Comp Magnums:

 

you can get the comp pro's full roller for $269. 7/16 stud and 1.6 ratio same price for the 1.5's and 3/8 stud. It would be well worth the extra 20. the part number cca-1301-16 Its on page 153 of the Jan-Feb issue of Summit.

 

really the steel stamped rollers are just a step up in performace and durability without a BIG step up in price. aluminum rockers are built to withstand the pressure, even from the pressure of those really tough springs. and if your using aluminum rockers, you should prob be using a stud gurdle (to look cool) which can minimize flex and maximize performance. basically aluminum is used because its less mass that needs to move, add to that those titanium retainers and those high-tech springs and youve got an awesome valvetrain, but thats mayb for higher RPM engines, still looks cool tho (which is what its all about).
aluminum rockers are all machined percisely so each one is the same. the steel stamped rockers are somewhat close but because they are punched, the dies can wear and you may get some rockers that have been punched just before the dies were replaced and some when the dies were just replaced but the tolerances are tighter because they are more for performance. those steel stamped rockers (NOT roller) are the worst, they are in-accurate and impercise because tolerances are looser.

 

Comp 1317 or 1318.

The Comp Pro Mags are not actually lighter than most aluminum rockers, but more importantly, have a design that produces LESS reciprocating mass, which is more important. You get the best of both worlds - Far stronger and more durable than aluminum, and less moving mass in the valve train than with aluminum rockers. Furthermore, they are rebuildable, with replacable roller bearing sets.

 

And only $25 more than you were thinking of wasting on aluminum:

http://cgi.ebay.com/Comp-Cams-1318-1...Vujnz9sgPAmUg=

 

Get the Comp Pro Magnums... they are absolutely bulletproof, and well worth the extra few bucks. I love mine, they are great rockers.

The only problem I ever had with them (as have others here at TGO) was not with the actual rockers themselves, sorta. What the problem was, is that a standard length SBC rocker stud is too short. The Pro Magnums have a substantially larger trunion, which is good for stregth and reducing friction, but it doesn't play well with stock legnth studs and heavy valve springs. The problem, is that when you have the rocker sitting on the valve spring and proper length pushrod, and you adjust the poly-lock, it doesn't "grab" enough of the threads on the stud, and with really stiff valve springs it will break the top of the stud off, as mine did.

The cure (if you have heads with screw-in studs) is some of ARP's rocker studs. They have a 3/8" set for the SBC thats 1/8" longer than stock, which is exactly what you need. I haven't had a problem since.

If you have press-in studs, you are out of luck unless you want to take your chances. With a factory valve spring, you'll probably be alright as they are pretty weak, but a real high-perf valve spring will probably cause problems like I described above.

But with the proper studs, they are easily the BEST sbc rockers out there IMO. Two thumbs up!

 

i have the summit rockers 1.5/1.6 ratio.. they are pretty good but i still adjust valves every 500-1000 miles.. my machinist said that he built a motor for a friend and put the comp pro magnums rockers and the guy checks the valves when he changes oil just to make sure.. not adjust.. check..

 

Are you running just a hydraulic cam? or a solid one? Seems like a lot of adjusting if it is just a hydraulic cam.

 

its a solid flat tappet.. comp 306S.. and the other guy has a solid as well..

 

Hmmm. I honestly don't want to "Bogart" this thread, but I've been paying attention to this since I'm building a fairly "*****-out" 383, & I have to ask - is this something that I should pay attention to? I've got AFR 195 heads with 7/16" screw-in studs, but this is the 1st time I've seen this, & it concerns me a little. Should I be concerned?

Thanks guys.

 

7/16" studs are good when you have very high spring pressures. The thicker stud will decrease deflection at high rpms. If your engine doesn't go much about 6800 rpm, switching to 7/16" studs and rockers isn't really worth it.

The cost of the rockers either 3/8" or 7/16" stud should be the same but if you're going to use 7/16" rockers, you'll need to upgrade the studs. Typically, the larger stud will still have the 3/8" base that screws into the head so holding strength into the head is the same.

 

Are you using Pro magnums? Then I guess so
If you're going high RPM (big cam), i'd also suggest a stud girdle. B&T (I think that's them, the torque convertor guys), have a nice one for $69 or something.

I'm fairly sure it's 7/16", for both, not 3/8" for both. 3/8" hole, 7/16" tap.

 

Another vote for Pro Magnum RR. After breaking 2 pushrods over the past 3 or 4 years, shifting at 7000 rpm and having a solid lifter cam, the rockers are fine.

 

This what what I was talking about, if you can see it in his pic, as its difficult.
See how deep into the poly lock the set screws go? They shouldn't go that deep, they should be about flush with the top of the poly-lock...that means the poly-lock itself doesn't go far onto the stud. I bet anything you're using std length studs right? If its working for you, great.. just thought I'd point it out though, as its a good visual example of what I was saying

 

And as a follow-on, what kind of valve covers are you full roller
guys using? How compatible are the stock low-profile center-bolt
units with any of these full roller rockers?

thanks,
kk

 

Pro Magnum rockers for BBC under stud girdles. The original poly locks are replaced with longer ones that the stud girdle bolts around. Depending on how tall the locks that you use are, you should be able to fit normal roller rockers under factory rocker covers. If the poly locks are tall or if you use a stud girdle, tall rocker covers are required.

 

They've been fixed since that pic Decided to replace all the studs when the last pushrod broke last year.

 

As nice as the Pro Mag rockers are, that photo makes me wonder if they should be used with stock length studs.

 

With any kind of a peformance valve spring, I wouldn't recommend it. Stock springs it would be just fine though.