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Discussion Starter #1
I understand the benefits to going to roller rockers over stock stamped, but is there a noticeable benefit (i.e. reduced friction, etc) to justify the cost of stamped roller tip rockers over standard stamped? It's obvious that there should be less friction between the valve tip and the rocker, but is there any noticeable performance gains with if all other factors (cam lift, valve size) remain the same?
 

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Hammer and a torch
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other than the benefit of taking the sideways pressure off the top of the valve (via the roller). Nothing is really gained by roller tip rockers... Just gives longevity... Also these are really for lower lift style cams and mainly the street... True brand name roller rockers are the way to go... BTW the newer stainless roller rockers actually have either the same or less weight at the valve as compared to an alum roller rocker...
 

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Big Block Z28
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I don't think you'll see "noticeable performance" improvements with just roller tip rockers, but I think there will definitely be an improvement and an increase in reliability over the stamped rockers. I think the performance improvement will show up in combination with a good cam and other mods. The cost isn't all that bad. Check Summit. They've got a few different brands. I ran Crane's on my small block chevy for over 10 years and drove it rather hard sometimes and never had a problem with them. I now have Harlan- Sharp's on my big block. Most of the roller rockers are similar, some have a difference in hardness. If you're not doing any serious racing you shouldn't need the "big bucks" ones.
 

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he biggest advantage of the roller stamped rockers is the increase of valve guide/stem life. Seals can do a better job when the valve stem is going up and down. Not up, down and to the side. Seats last longer too.
 

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roller tip rockers

Roller tip rockers reduce valve stem wear as there is not lateral thrusting motion on the valve with roller tips.
As for roller tips, themselves, adding horsepower, yes they do by reducing friction loads. What it will normally amount to is maybe 1-2 hp gross gain, due to the reduced perisitic load. Full roller rockes will pick up a couple more hp due to the added reduction of perisitic loads, but as a power booster in themselves, they cant really be classified as a true hop up tool as much as a life extender for your valve train, because of the reductions in friction loads, and with the lighter rocker arms, less weight for the springs and lifters to deal with.
But as a $ for $ hop up item, compared to other things, no they arent a big power builder, and what gain you do get, you probably wont realize, unless you put the engine on a dyno.

IF you go to a higher ratio rocker arm, for instance, on an SBC, from a 1.5:1 to a 1.6:1 ratio, you will see a 7% increase in valve lift but no change in your duration, as duration is effected by the lifters contact with the camshaft. However, your valve duration will increase a very minute amount.

From dyno tests, stepping up in ratio as exampled here, can show an increase of as much as 2-3 or even 4-5 hp at all measuring points through out the power band. However, going with higher ratio rockers can not be construed as a pure hop up tool, due to these small gains, but are more of a fine tuning tool, to exact all the power out of the given power band.

I suppose that one could say, if you added the power increases made by the higher ratio rocker arms, at all the measuring points, generally in 500 RPM increments, if you have a net gain at each point, you could theoretically have a power gain of 12- 35 HP, total through out the power band, which is normally considered to be 3000-3500 RPM. While you certainly wouldnt feel this gain by the seat of the pants, It could well show up in your 1/4 mile times, depending on vehicle weight etc etc etc.
 

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This topic has come up before and there are differences in opinions (as with a lot of things in hot rodding).

The only true gain you get is from the more accurate ratio. Stock rockers are often way off (not a true 1.5:1 like they are supposed to be) they can vary quite a bit. The roller tip rockers are usually made better.

As far as the roller tip, it doesn't really even roll. With the preasure from the springs and cam the roller just slides. The oil is less friction than the roller tip. Meaning the tip on roller rockers don't have needle bearings in the them it is a steel roller on a steel shaft, the tiny contact patch between the roller and the valve tip (covered with oil), this results in the "roller" tip sliding just like a non roller tip, except for the smaller contact patch.

This was proven with a high speed video set-up (slowed down of course). I can not find that again I have tried. Something you might want to research.

Royce
 

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ratio changes

The only major considerations with going to higher ratio rocker arms is if you already have a very high lift, running into a situation where valves and pistons collide, making expensive noises, and the other is with the ball fulcrum roller tip rocker arms, the rocker arm not bottoming out against the rocker stud.

If you are running a mild cam, that doesnt have a lot of lift, then as a rule there are no other changes needing to be made. Just bolt them on, and set your valve train.
 

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rockers

Royce makes a good point. The brand name aftermarket rockers have a more accurate ratio. If you have ever put a dial indicator on the retainer and checked total lift you will know what i mean....I have never personally seen it but some of the dirt track engine builders I know have found stock rockers as far off as 1.2 on a 1.5 rocker!!!!

Keith
 

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Rocker Arms

k-star and Camaroman are both right about the more precision aftermarket rocker arms. I didnt bother to open that window, as being me and ASSUMING, that most people knew that already, however, thats not always the case.

However, In defence of FOMOCO, I have done just that kind of test and found that for the most part, whether the cast rocker arms used in earlier small blocks or the stamped as used on the later small blocks, Winsors, and all the clevelands and Limas, that as a rule they have been pretty close. On the cast 1.6 rockers I have found them to be as far off as 1.55 to 1.65. I have gone to the effort in years past to box them up according to those figures and matched them up with rockers of similar error, on beater engines.
On the stamped 1.6 and 1.73 ratios I have never found one off more than .05 in ratio.
 

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fomoco

Keith, i agree. it seams to me ford has the rocker program together compaired to the gm and mopar set-up's...

Keith
 
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