SPANKY LS1

iTrader: (24)

I know that they add reliability, but few stock rocker arms actually fail. I know the stockers can flex at high lift, but at what point does that become a concern? Say on a mild cam, like a 224/224 .580 would they possibly flex enough to actually cost power, or would they be more likely to flex on a big cam, say a 232/240 .600?

At what point do they become "necessary" to avoid losing signifigant HP? Anone actually noticed a gain from these, or just piece of mind?

Shawn

gomer

iTrader: (13)

I do a good bit of dyno testing with my car and I belive that the YT's didn't gain me anything. That's just my opinion, but I feel like I could have spent that money on something else that would have gave me more benefits.

dlandsvZ28

If I had to do it over again, I would have bought new stock lifters and spent the difference on a set of ET streets.

ET streets/Nittos/ or suspension pieces will lower your timeslips more that Yella Terra rockers.

01PewterWS6

Yeah but are stock rockers strong enough for a TSP 231/237? and spining the motor to 6800?

Damian

iTrader: (89)

Shawn there's a local guy that didn't see anything on the dyno w/ the YT's. I think his only change was an empty wallet...

josh

C4VetteLS1

Just buy new stock rockers....with any cam

dlandsvZ28

For my application (224/228/581) and since I on rarely go to the strip and dont' rev to 6800 since the cam max's at 6200, IMO for me, the money spent on YT's should have been spent elsewhere. My car is a street car and I don't drive around 99% of the time spinning it to 6800 rpms.

But if I did plan to spin the motor to 6800 and race weekly, the rods would probably go before the stock lifters (but that's just my humble opinion).

I think a good answer depends upon the application and the intended use of the motor and the car.

9T9BlueTA

iTrader: (2)

I got mine for piece of mind just like the replacement oil pump.

99 Black Bird T/A

iTrader: (4)

Anyone have proof the stock rockers actually flex at .580 lift? How much? How about at .560 lift? How much?

My pet theory is the stock lifters bleed down a little so a .580 might be more like a .570 etc so the stock rocker deflection is probably pretty meaningless in our applications with .580 lift cams. I don't think the difference in lift will be meaningful as duration and ramp rate are more critical most of the time.

BTW - I know someone that had two stock rockers go bad at different times.

Mike K.

they yt's actually weigh more at the head than the stock rocker so it is possible that for power issues they may actually cost a little hp.

01PewterWS6

I am just worried about strength anyone running these with a big cam?

VX 255

Would the change of ratio from 1.7:1 to 1.8:1 be worth any Hp ?

Mike K.

it would be worth more power but generally people like to use the bigger cams to get the better lift numbers rather than the rockers.

jmX

There was statistics posted a while back about how much a stock rocker flexes compared to a YT rocker. The stock rockers weren't bad, but they did seem to show a 10-15 thousanths flex when used on something like 350lb springs, so that takes the cam down a little. If that data was indeed true, everybody that thinks they are running .560 lift cams is actually running .545-.550 lift at the valve, and so forth. With the YT's it was something like 1-2 thousanths.

Anyway, I personally don't own a set, so I certainly don't think they are necessary, but they are nice for those that have a little disposable income for peace of mind (spanky, hope you dont mind I changed your typo in the thread title...it was bugging me ..."piece of mind" is something that Hannibal Lecter would like), because I've definitly had to change out a few stock rockers that puked their bearings out into the engine (none on my own personal car).

Cal

iTrader: (1)

I installed YTs because I didn't like wondering when the stockers would sling a needle bearing, so I wouldn't loose lift, and so the rockers would never limit the safe rpm of my engine. I also didn't like the way the stock valve train is "almost" a full roller system; only the rocker tips don't have rollers. The YT's took care of this and replaced a part that was marginal on strength with one that is over kill. Also, for the type of racing I'm interested in, the engine must handle sustained high rpm operation, as opposed to drag racing where it's all over in a few seconds.

LS1LT1

iTrader: (16)

How about on a stock internal (stock heads and cam) motor, would the YTs (or Crane, SLP etc.) net any useable gains, or at least any gains that justify their cost/labor?

Pro Stock John

iTrader: (34)

I have seen 3 or 5 dyno sheets that showed a +5rwhp just on the dyno. I think for folks spinning combos high (mine is set up for 7200) it's piece of mind. There is a TSB on stock rockers loosing needle bearings it happens more often than you think. And I also did them for the reason that jmX mentioned, the stockers have more deflection.

LS1x2

iTrader: (11)

I couldn't justify the expense even with over .600 lift and spinning past 7k pretty often. I have only seen stock rockers fail when other things broke first, like valve springs.

Ryan02SS

iTrader: (3)

I did mine mainly for peace of mind and also for the added benefit of making my setup a full roller like Cal has mentioned above. The less friction you have then the more power you make. With the reduced friction from the rocker tips is it worth the $400 for maybe 5hp well you decide but I had the $$ at the time and was changing valvesprings anyway so I went ahead and ordered them.

jmX

FWIW, Both cars I had to fix were bone stock.