joelvette

iTrader: (11)

I've already got a set of harlland-sharpes but my tuner recommends going back to upgraded stocks for the lighter weight, but you loose the roller tip. going to be about .600 lift. I can probably sell the Harland-sharpes for about the same price as a set of upgrade stock rockers, or close to. which one should I go with? if you've got some experience with this, please chime in. thanx joel

2011grandsport

I upgraded my stock rockers with the trunnion kit when we installed the new cam. Cam is .590" lift as noted in sig. From what i understand about the rockers are full rollers are heavier on the nose over the valve than the stocks. If this is going to be a daily driver then the harland sharpes would be the best due to they will not wear the valve guides with side loading like the stock ones do. I used my stock rockers for one reason cost, just trying to keep it in a budget.

ls1 1990 VN

I had H/S with my old engine.. stock block, TSP 231/237 cam, Patriot Gold springs Ti retainers.
Shifted at 6800rpm would go 7000.

This build in Sig, the Patriot springs were no good, also the H/S rockers were to heavy on the valve.
BTR .660 platinum's & stock rockers with Trunnion upgrade fixed the issues.

HioSSilver

iTrader: (8)

I spun my bolt-on ls6 to 7000 with hs rockers on the stock springs. I put a set of 1.8' hs rockers on it with a set of psi beehive springs and still spin it 7000.....and would not be scared of 7200 or 7300.

Hs rockers are heavier......but i noticed a smoother running engine at high rpm with them.

96capricemgr

iTrader: (1)

Stock cam is easier to control than most aftermarket.

HioSSilver

iTrader: (8)

True.....maybe. i guess it depends on how the lobes are designed.

I just offered my experience with the rockers.

I would like to know op's combo and aspirations with the car before recommending anything really.

JakeFusion

iTrader: (7)

If you really want to use a Roller Rocker, I think the YT with the 10mm base is a better option than the HS rockers. They are lighter and have a more rigid base, so they deflect less. The YT's weight make them need less spring rate to control than HS as well, but still less than stock - say a 450lbs spring open for YT vs a 380-400lbs spring for the stock rocker with the same lobe - but it may not RPM the same as the stock rockers (I'll discuss that below). Also, the YT 10mm requires machining of the heads vs the stock 8mm stud, which is not a huge deal.

As far as the RPM statement goes, PAC did testing with the HS rockers (which are heavier than YT) and the HS were never able to RPM as high as the stock rockers, even with a lot more spring rate on the same combo. I think they experienced valve float about 500 RPM earlier than the stock rocker. They tested with the LSL lobe, which is not a mild lobe by any stretch of the imagination, but it was designed for stability.

The point is, it comes down to combo, like everything. So lobe selection, pushrod stiffness, valvespring weight, and valve weight all play integral roles in achieving desired results. The YTs are less heavy over the nose than the HS rockers and with proper spring pressures should be able to RPM about the same as stock with less friction. It might be worth 5-7HP at the very top of the RPM range if you are controlling the valve.

It's hard to beat a trunion upgraded stock rocker tho. It's cheap with the trunion upgrade and is steel and light. Both those attributes make it less prone to breaking. These HS and YT rockers are both aluminum pieces... and with higher spring rates are prone to fatiguing sooner than the investment cast steel stock rockers. Just another thing to consider if you're going to be putting miles and miles on your combo.

HioSSilver

iTrader: (8)

What are those rpm limits Jake?? For sure it's beyond 7k so it may or may not matter to op.

What is the nose weight of the YT rockers? I posted the weight of the stockers and the HS on here before but I forget what they were exactly. I can weigh them again if you guys want. But i would like to know the nose weight of the other rockers also.

Since my engine is a ls6 it has light weight valves......which should should never be over looked in a hydraulic cammed push rod motor.

SoFla01SSLookinstok

Good info & it does come down to the combo.

I'm running the H/S. My valve train was put together with them in mind. From the lifters to the valve springs. Martin@Tick helped me choose the right parts as well as my custom cam.

I also only spin my motor to 6500 max.

JakeFusion

iTrader: (7)

You're right Hio. In most cases, over 7K doesn't matter in a hydraulic setup. But a lot of early TFS heads had valve float after 6300 or so with HS rockers because they didn't have enough spring on the head to control them. That's why you saw the switch to the YT rockers... and then the breakage from the higher pressures and aluminum rockers. But they were trying to control a heavy valve with crazy lobes and flimsy pushrods a lot of times.

Now with what 3 or 4 revisions, the YTs are stronger than they were and are a pretty solid choice. I don't have the weight of them over the nose, though. It's less than the HS's tho.