Destructimus

Hey I have a few questions about roller rocker arms.

1. Say I have a stock engine. What can I expect to gain as far as HP goes?

2. How do I know whether or not to get 1.5 or 1.6? Whats the difference? Do I have a choice as to which way I go? What happens either way?

3. Are they just a simple bolt on where all I basically have to do is remove my valve covers and bolt them right in place of my old rocker arms or do I need to do any kind of valve adjustment.

Sorry for being a moron guys. I'm determined to do all the bold ons I can this year because I don't have money or time to really do something major right now... Thanks.

Apeiron

Practically none.

The rocker ratio is the ratio of cam lobe lift to valve lift. A stock 1.5 ratio arm opens the valve 1.5 times the height of the cam lobe. A 1.6 rocker will have a little less than 7% more valve lift than stock.

You remove the valve covers, bolt them on, and then adjust the valve lash.

Sonix

iTrader: (1)

1) Just roller tip rockers? Maybe 5HP. It just saves a tiny bit of friction.
2) Your valve lift is determined by that ratio. 1.6 gives more lift. I forget what the stock lift is, but you get a bit more then. That gives you another 5-10HP.
3) yea, "bolt on". You don't bolt them on so much as lash them on. So you need to adjust the valves yes.
That's all there is to it. It's easy but you're not getting a lot from it either. HP/$ isn't all that great.

Destructimus

Thanks for the info guys I appreciate it.

Air_Adam

On a stock engine, the only real benfit is that they make the valvetrain substantially more stable and accurate. The stock stamped steel rockers are pretty flimsy, even with wimpy stock valve springs, and do flex - some more than others - so there is some variation to the valve action from rocker to rocker. A *good* quality set of roller rockers (Comp Cams, Crane, GMPP, etc) are much stiffer and much stronger than stock rockers, so everything in the valvetrain will operate much more as it is supposed to. You won't get any real noticeable power gain from them, if everything else stays the same - like the cam and valve springs.

Apeiron

A roller rocker trunnion will also allow a cam with more lift to be used, which doesn't matter if nothing else is changed.

dv8

iTrader: (9)

My two cents. When buying your roller rockers you'll need to determine if you need "Self Aligning" rocker arms. Are you running Guide Plates for your pushrods? Will you need to have screw in studs installed in your heads. If you dont have the guide plates or screwin studs. Look for a stamped set of self aligning roller rockers, Ive used comp cams and have been pleased.

Apeiron

If they're stamped they'll be roller tips instead of full rollers.

Trick414

It depends on which way you look at the issue whether it is worth it or not.

My view is yes, at least based on what it seems you are trying to accomplish given your brief post.

Essentially, with this simple "bolt-on" you are paying for a few HP and a some reduced friction, and a whole lot of education.

You have to look at the engine and the rest of the drivetrain as a system that works together.

Here's a story: Many years ago I restored a 1978 Trans Am. It had the so-called "high-output" Pontiac 400 good for something like 220 whopping HP. (Of course, it could pull a semi-trailer, but that's a different story).

Back in the pre-internet days, you had to go around to car clubs and talk to people, read magazines, and get friendly with a whole bunch of mechanics that may or may not know a whole lot about producing power.

In any case, what I learned was that performance is a result of balanced application. If you take your engine right now, and swap in a huge cam, you probably won't see a drastic difference. In fact, your performance may decrease. That doesn't mean the cam is bad, just that the other components haven't been balanced.

In your case, if you have a roadmap in mind on what you want to do with this engine, then grabbing the roller arms now won't hurt. That is, if you know that down the road you are going to build this engine and utilize these exact rockers, then bolt them on.

As for 1.5 or 1.6, it really depends on what your ultimate "balanced" motor is going to be. Given your current stock motor, the 1.6 rockers (like the 1.5s) will free up some friction/drag and maybe allow a few more top RPM's (which might translate to a few more HP). In addition, they will also "make" a more aggresive cam and possibly produce "some" performance. In reality, though, they are just getting you ready to beef up the engine in other areas.

Going back to my Pontiac 400, I ended up with these items:
Block bored .40 over
Forged TRW pistons
Rotating assembly blued and balanced
Cam was (I think) a Crane repop of the old Pontiac "R" or "S" specs
Ported heads, oversized valves (can't remember the specs... 2.11/1.94 I think)
Harland Sharp Roller rocker valvetrain with 1.6 ratio, hydraulic lifters (don't think rollers were available then, at least not for street)
1970 Ram Air repop cast iron "headers" with dual 2.5" exhaust, no cats
Edelbrock 2 plane intake
Holley Pro-jection 2bbl fuel injection kit
Accel blueprint HEI distributor
Fluidampr harmonic
BOP adapter plate for transmission
700r4 non-electric transmission with 4th gear WOT package, 3.42 rear posi

Basically, there was nothing crazy about this build. But, it all worked together. It probably only realistically pulled about 300hp. The torque was, given its Pontiac heritage, much stronger. Since it was a balanced build it made HP from off-idle all the way to 5500RPM, which was unheard of in a street 400.

Destructimus

Cool stuff guys. Thanks. Still haven't decided what I'm going to do. It really depends on how much time, money, and info i have on everything by the time I need to get this car back on the road.

tony_cogliandro

iTrader: (3)

i know this is an old thread but its pretty good and i wanted to ask one question in it. when i look for full roller rockers i see a lot that talk about pre 87 heads and post 86 heads. since we mix and match heads a lot - what is the difference? i know the difference in the heads themselves, but why do you need different rockers - when you look at them they look the same and the stats dont appear to differ, and you can get them self aligning too, so what makes a rocker for a pre 87 heads and one specifically for post 86 heads?

1991CamaroRslow

iTrader: (3)

The center bolt valve covers and the width of the pushrod holes/type of push rods is the difference. You need a narrow body for the center bolts, you need hardened push rods if you run guide rods (non self aligners) or are using the heads with the ovate holes the 87's had. The most confusing thing I've ever ran into was my 87 heads, they had NON self aligning rocker arms but no guide plates, the heads were center bolt, but they had very narrow ovate holes for the push rods. I used self aligning narrow bodies anyways, better safe than sorry.

tony_cogliandro

iTrader: (3)

that is good information. thanks - i may end up putting 601's on the car and that means another headache - so my zz4 pushrods are too big - i will need to machine them out? when i tap the stud mounts for screw in ones. then there is shaving the rockers to handle the 1.6's on the intake and even the exhaust since the 1.5's will be pushing .510. and then there is the difference between self and non self aligning rockers. DOES THIS EVER END?
oh - i forgot i will have to machine my tpi so the center 4 holes will go in at 90 degrees instead of 72.
MOMMY MAKE IT STOP!