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Roller Rockers - Rock On, Rockers!
Setting up guide plates and installing roller rockers.
Jun 12, 2012
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Memphis, TN 38118
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Roller Rockers - Rock On, Rockers!
Here are all the components we ordered from Comp Cams to update, strengthen, and refurbish the bulk of our valvetrain. The main part of this is the next generation of Ultra-Gold ARC series aluminum rocker arms. They have been designed to enhance valvetrain stability and improve oiling while fitting under stock valve covers. Exclusive spiral lock type clips replace retaining clips for improved durability. They come in 1.5, 1.6, 1.65 with 3/8 or 7/16 studs for the small-block, 1.7 on a 7/16-inch stud for the big-block, and 1.72 and 1.82 on a 8mm stud for the LS series. We'll go into more detail on the other product later in the story.
Before any of the new parts are installed, Comp instructs you to soak everything in lacquer thinner or denatured alcohol to remove any possible contaminants. The parts are soaked for a minute or two and then blown off with compressed air.
Next, the rockers are soaked in a nice bath of oil. This will prevent galling or damage when the engine is first fired up and the oil has yet to get all the way up the pushrod to the rocker. Just make sure you have all the moving parts submerged in oil. We went with Comps own 10W-30 muscle car and street rod engine oil. This stuff is the perfect blend of mineral oil and synthetic juice for our solid lifter non-roller cam since it has optimum amounts of ZDDP (Zinc and Phosphorous).
While our rockers were spending some time at the spa we focused our attention on removing all the old components. When removing poly locks, loosen the outer and inner portions together instead of trying to bust the lock insert loose by itself. We also recommend rotating the engine so the rockers you are removing are not trying to open the valve. Once you have loosened the poly lock it should simply thread off of the stud, which allows the rocker arm to slide off.
The heads on our 350 have screw-in studs so all we needed to do was break them loose with an impact and then finish removing them with a ratchet. The studs run into the water jackets so there is going to be sealant and possibly some rust accumulated on the threads, taking them out slowly should prevent messing up the threads in the head.
To give you an idea of how rocker arms have evolved, check out this comparison shot. Our take-off rocker was not only showing signs of wear, but it has a very small pivot shaft compared to the new Comp piece. You can also see that the material has been moved around in the design to increase strength where it’s needed. We are not here to say our old rockers were a bad design, as they lasted almost 25 years on a solid-lifter, nitrous motor, but with the improvements of our new rockers and the larger stud size, the new ones should last even longer. The inset shows the roller tip cutting into the side of the body on our old rockers, revealing why we are even going down this road.
We are going to upgrade from a 3/8 stud to a 7/16 stud. The lower threads are the same so it is just a simple remove and replace. The larger studs will be stronger and will have less deflection giving the rockers a more solid foundation, which in turn will extend their life and performance. The two-piece guide plates are a new product from Comp and are a welcome addition to the product line. The interlocking design enables a reliable and true adjustment in the one axis needed for most valves. This prevents issues associated with prying or cutting the guide plate, especially on heads with altered valve centerlines.
Our pushrods are staying the same diameter but now instead of the two-piece design we are upgrading to Comps Magnum pushrods. These are an affordable 0.080-inch wall, heat-treated, chromemoly pushrod with precision formed, reinforced ends. We ordered a set that measured 7.800 for this engine. If you are setting up from scratch, you should invest in an adjustable checking pushrod (Comp has a many) to help you simplify the job of figuring out proper pushrod length. We just measured our old ones and got the matching size.
Since pushrod length determines where the tip of the rocker arm hits the tip of the valve, we did a quick check to make sure we were still in good shape. We didn't have any of the proper marking compounds you usually see, but a Sharpie will work in a pinch. We colored the tip of the valve completely.
Next, everything was temporarily installed and the rockers set with just a little lash. Then we rolled the motor over a few revolutions with a starter button.
After tearing off the rockers, our faint contact patch was revealed. The patch is the rocker sweep on the tip of the valve through full articulation. Ideally, you want it to fall just above center because when the arm starts to push down on the valve it move forward just slightly. If yours is not in the proper position, you'll need different pushrods. Longer ones will move the patch towards the intake manifold while shorter will move it towards the headers.
We were all good so it was time to install the stuff permanently. The threads on the studs were coated in ARP thread sealant and anywhere there could be metal to metal contact was coated in ARP assembly lube. We'll coat the top of the pushrod with assembly lube when we put the rocker on so we don't accidentally smear the stuff all over the place.
With the studs hand tight, the guide plates were adjusted to position the tip of the pushrod in line with the stud and valve tip.
Once Ali had everything in a nice straight line the studs were torqued to 60 lb-ft, effectively locking the guide plates in place. This should be enough but, if you are going to service your motor a ton, it might be a good idea to tack weld the two pieces of the guide plate together.
Ali rolled the motor over until the exhaust valve just started to open. Then he set the intake lash. With that done, he rolled the 350 over some more until the intake opened and started to close. Right before the intake was closed he stopped and set the lash on the exhaust. This will ensure the valve you are adjusting is on the base circle of the cam. For our Isky Z-30 camshaft, a cold lash setting of 0.032 is recommended so that’s what we set them to. This seems a bit excessive so we may go back after and tighten them up a bit. Without pulling the heads to confirm our piston-to-valve clearance, we could induce piston to valve contact doing this, especially since the rocker ratio has been upped from 1.5 to 1.6.
With the lashes set, Ali now tightened the poly locks. Since the outer barrel of the poly lock sets the lash, you want to hold it in position while you tighten the center lock. This should be sufficient to secure the rocker arm, but we have had one come loose before so now we are a bit more careful. We give the wrench a little bump with our hand; yes, it will slightly lower our lash setting, but it's worth it to ease or worrisome mind.
Ali repeated the procedure for the remaining cylinders before the valve cover was reinstalled. We pumped the gas and hit the key. With a resounding vroom, the motor came to life, and boy does it sound sweet. We let it come up to operating temperature and then went back and set the hot lash of 0.030. Then we did an oil change with the Comp muscle car oil to properly protect our flat tappet valvetrain. Now we can flog the car with the knowledge our rockers will stand the test of time. Rock on, rockers!
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In this tech edition, we engage in setting up guide plates and installing roller rockers. Click here for more details or check out the August 2012 issue Super Chevy Magazine
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Looking to upgrade your rocker? Then follow along as we swap out our old steel rockers for some Comp Cams Ultra-Gold roller rockers, only at Chevy High Performance.
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