Cliff your thoughts on roller rockers?

[Mudsport96]

I saw you commented on things not to waste money on in another thread. So, not wanting to clutter someone else's thread I figured I would ask here.
I know and have seen that the heavy roller tip rockers can cause valve train stability issues. But what are your thoughts on just roller fulcrum rockers?
I have 1.6 Harland Sharp full rollers on my engine.  I did not buy them, they were on it when I got it. The heads were bare when the engine was machined so it got screw in studs, guide plates, and some mikd bowl work. With the slow ramps and mild lift of the old school High Energy cam the 1.6 helps get more lift without the radical Extreme Energy grind.
I don't have float problems because it has the highest spring pressures that Comp recommend for that cam and it is also admittedly a mild cam that makes max power at probably 5000  So other than the expense and weight issue, what are the drawbacks? I have checked stock rockers and seen Ratio variations from 1.3 to 1.55 on stock stamped rockers. So if nothing more than consistency I personally like aftermarket rockers.

[Cliff Ruggles]

Most of the information on stamped steel rockers arms being all over the map for ratios is regurgitated from information that wasn't all that accurate right to start with.

Stamped steel rockers are light, strong, and good for most of these engine builds.

I do NOT like or use the "roller tip" varieties.  Comp Cams roller tip rockers, for example are heavy, and poor fit to the grooved rocker balls they supply with them.  They "grind" in and turn blue and even black from the heat. 

The grooved rocker balls are also a design flaw as they allow the oil from the pushrods to run straight down the studs and back to the sump vs "pooling" on top of the rockers and getting atomized for lubrication and cooling of the springs and other related parts.

Almost all roller rockers being offered are pieces of bovine excrement (imported).  The only ones I would even look at using are Crane Gold Race (not even sure they are still available), Harland Sharp, or Crower Enduro.

The rest will have low quality imported needle bearings, weak rocker bodies (cracking or letting the pins slide out at the roller tips), or grind up the inside of the rollers a the pins.  Even some taunted to be high quality parts have failed miserably where we tried to use them here. 

Scorpion, for example are supposed to be USA made, but I doubt it.  We tried a set and cracked nearly all of them at the roller tip end.....junk!

Tried PRW stainless full rollers and ground up all the rollers at the pins and put TONS of ground up metal into the engines........FWIW.......

[Mudsport96]

I have heard similar stories about the failed fulcrum needles. The set of Harlands on the car are from the early 2000s and have at least 10k miles on them. So I'm hoping they hold up for a while yet. The original owner that put it together was dead set on rollers and hell it was his money so I had no say. But, it runs great, if someone made a 1.6 rocker in the standard stamped steel style I would probably run it just to be safe.

[quadrajam]

I have stamped steel 1.6 rockers in my 350. Got them from SUMMIT.
Good point about the oil pooling Cliff, I would have never thunk it.

[Mudsport96]

Quadram, are they roller tip or factory style slipper tip 1.6s?

[quadrajam]

Slipper tip.  Part #  SUM-G6801. about $75.00 . Long slot grooved balls 3/8 stud.
Set of 16.

The ball grooves dont go all the way down to the hole although some oil could
possibly drain into the slots. I noticed when priming my engine that oil pooled in the ball
area on down to the rocker tips.  No problems so far @ ~5000 miles.

QJ

[Mudsport96]

Awesome. I will look into those, I don't know how accurate my logic is on the subject. But I do know the faster ramp flat tappet cams have issues. So, maybe you can speed up valve lift some with higher ratio rockers. Maybe I'll get a set for just in case scenario.

[77cruiser]

So far my Scorpions are holding up fine, but anything can & will happen sometimes.

[Cliff Ruggles]

Grooved rocker balls are a HORRIBLE invention.  They give up bearing surface area and allow oil to drain down the studs instead of "pooling".

I found this out decades ago after watching them in action on a running SBC engine with the valve covers removed. 

The aftermarket roller tipped steel rockers also have a very POOR fit to the rocker balls and "grind" themselves into a better fit creating a butt-load of heat and putting a good bit of metal into your assembly. 

I can't remember removing a set of Comp roller tip rockers that weren't blue or even black and heavily worn where they balls ride in them.  They are pretty strong and don't fail, so most folks using them don't even know this is happening.

The other problem aftermarket roller rockers bring to the equation is weight.  Anytime you add weight above the cam lobes it REQUIRES more valve spring pressure to keep things in check. 

So keep that in mind when you buy cam "kits" with HUGE heavy retainers, locks, springs and then add heavy rocker arms to that equation. 

The problems with controlling valve action are further compounded by using cams with "aggressive" lobe profiles.  These "new" cam offerings often reduce seat timing, then get the valves up much quicker and set them down faster as well.  NONE of that is a good thing when it comes to having a stable valve train.

About the only cam designer that paid attention to all that was Harold with his Ultradyne cams.  Although they never really got off the ground Harold sold his lobe profiles to Lunati and pretty sure Bullet Cams. 

I'll add here that reducing seat timing then shoving the valves open faster to increase .050" and .200" numbers does NOT mean your engine will make more power.  Time off the seat trumps all that so a slightly longer duration cam, even with slower ramps and less lift can and will make as much as or more power than the "whiz-bang" lobes cam companies are promoting these days.

I am probably the only one who has actually back to back tested that deal and found that due to the lifter diameter flat camshafts just don't do all the great things they tell us when you buy into that technology. 

You also have to factor in the increases in dynamic compression and pulling peak VE down in the RPM range.  This fact can quickly make a relatively "low" compression engine not liking pump fuel much and pinging on it. 

Despite the proverbial "brick wall" of 9.5 to 1 for pump gas you just can't make big power at low compression ratios even with fancy cams in these engines.  Compression is your friend with these things and you can make a LOT more power with higher compression, longer seat timing and wider LSA's plus enjoy smoother idle quality and improved street manners at the same time.......I'll sit down now.....

[Mudsport96]

No need to worry about taking a seat Cliff. I asked because I look for your opinion. Following advice I have gotten from here, I have helped people with problems that they had been fighting. I've talked others down from the "I need roller rockers" ledge, as I feel quality is not as good as I needs to be. Like I said before, the only reason I have them is they were already on the car. And they seem to be quality pieces from Harland, so they stay for now.

[Cliff Ruggles]

Also keep in mind that there are a LOT of products available and in use out there that don't make the grade.  Roller rockers is one of the WORST places to spend money in search of more power and reliability in long term service.  You add more places to wear out, like a pin with a roller on it, and they are drilled and pressed fit into the end of the rockers weakening them in that area.  If you go with full roller rockers you add needle bearings and we've seen enough of those get ground up to avoid any of the "low" end imported rockers altogether.

If you don't think aluminum roller rockers have potential trouble areas take a look at the cracked Scorpion roller rockers above.  It was installed in an engine here about 15 years ago.  They only lasted about 4 seasons of racing so had very little actual time or "cycles" on them.  They were sold to my customer (I was hired to assemble and dyno his engine) as a "package" with a roller cam, springs, and heavy retainers with 10 degree locks......