Aftermarket Rockers or Stock???
01-09-2008, 09:38 AM
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Aftermarket Rockers or Stock??? I am about to be building my Ls6 block with the PRC 5.3s and the Ms3 cam. Should i reuse the stock rockers or go with a set of performance rockers? I want to get all the horsepower i can but im not sure which rockers would perform the best.
01-09-2008, 09:54 AM
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I have a thing for the Harland sharps. Good quality rocker for the price, unless your stepping up to a Jesel. But for that setup a Harland Sharp rocker set would be the way to go in my opinion. I have plenty sets sitting in front of me, let me know if you need some buddy.
-Marcus
-Marcus
01-09-2008, 11:31 AM
#3
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Rockers We have had very good durability out of the production rockers. We have also not found any of the aftermarket rockers to provide better high rpm operation (the factory rocker is a very low rotating weight/inertia design). We have had some of the aftermarket rockers actually cause valve float due to the increase mass of the rockers (change to stock on the dyno and the problem goes away).
We run the factory rockers on almost all the engines we build (other than the mechanical roller conversion engines that need an adjustable valve train).
We run the factory rockers on almost all the engines we build (other than the mechanical roller conversion engines that need an adjustable valve train).
01-09-2008, 12:25 PM
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I have a thing for the Harland sharps. Good quality rocker for the price, unless your stepping up to a Jesel. But for that setup a Harland Sharp rocker set would be the way to go in my opinion. I have plenty sets sitting in front of me, let me know if you need some buddy.
-Marcus
-Marcus
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01-09-2008, 02:12 PM
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I'm not an expert, but IMHO... the rockers will not give you any performance gain unless (as described) you're experiencing valve float and losing power. Mass is critical with all reciprocating and rotating parts. The valve train is reciprocating and needs to be as light as possible. Your springs must be sized to overcome the inertial forces from the mass of the rockers so more weight, bigger springs, greater forces and theoretically more parasitic loss.
The advantage of aftermarket rocker is longevity and where needed adjustability.
The advantage of aftermarket rocker is longevity and where needed adjustability.
01-09-2008, 03:57 PM
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I have seen stock rockers go into the 11's and then some. If your a scavenge racer, they are worth it. By scavenge you are trying to rape ever last horsepower unit out of the motor aftermarket is worth it. When you step up and get into the high horsepower, low et applications hands down you need a new set.
01-09-2008, 04:03 PM
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Well im not planning on going to the track much...so times dont mean anything to me. I just want a fast street car. And i just wanted a good setup on my new block.
01-09-2008, 04:19 PM
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Bang for the buck you can put stock on it. But like i said if you want every bit of RPM and power, bigger ratio Harland sharp from me is a good way to go.
-Marcus
-Marcus
01-09-2008, 04:22 PM
#18
Here is my take on things. Stock rockers have a pretty wide wipe pattern and move from the intake side to the exhaust side of the valve. Stock LS1 seat pressure is low, less than 100 lbs. Low seat pressure and low lift equates to acceptable valve guide wear.
Now lets look at an aftermarket cam. Lift is higher and ramp rates are faster. Higher lift translates to a wider wipe unless you take the time to figure out if shimming will bring the wipe pattern to an acceptable width (on my setup I was not happy with the wipe pattern I was achieving and some were not even centered front to back). Faster ramp rates and higher lift requires stiffer springs and more seat pressure to control the valve train. So now you have wider wipe and higher loads, and as a result, more valve guide wear. With aftermarket bronze guides and all these other factors, aftermarket rockers correctly set up to minimize the width of the wipe pattern, will minimize valve guide wear. To me, that is worth the price of the rockers and not the few hp that might be achieved in the swap.
Now lets look at an aftermarket cam. Lift is higher and ramp rates are faster. Higher lift translates to a wider wipe unless you take the time to figure out if shimming will bring the wipe pattern to an acceptable width (on my setup I was not happy with the wipe pattern I was achieving and some were not even centered front to back). Faster ramp rates and higher lift requires stiffer springs and more seat pressure to control the valve train. So now you have wider wipe and higher loads, and as a result, more valve guide wear. With aftermarket bronze guides and all these other factors, aftermarket rockers correctly set up to minimize the width of the wipe pattern, will minimize valve guide wear. To me, that is worth the price of the rockers and not the few hp that might be achieved in the swap.
01-17-2008, 08:05 PM
#19
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