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| Available now for delivery | Available Winter 2002 | Available Later | ||
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The Hotrocker system bolts on in place of your existing rocker arm system on engines with individually bolted rocker arms. On iron head Chevrolet small-blocks with press-in studs, the heads have to be prepared for screw-in studs before our system can be bolted on.
$995.00 + $30.00 handling for V8 engines
$895.00 + $30.00 handling for V6 engines
Many dynomometer tests on various engines with different camshafts as well as years of use on the street in daily driving have proven the durability of the Hotrocker.
The rocker arms are made of hardened 8620 investment cast steel. The rollers are 8620 hardened steel, the shafts are cold drawn 4140 steel hardened by a special ion nitrate process that eliminates galling, the primary event in metal wear. The pedestals are made of 4140 investment cast steel as are the hardened caps which attach the shafts.
The steels and hardening processes have been chosen for wear resistant and toughness. They guarantee trouble free operation at all three potential wear-points-The pushrod socket/adjuster, the teeth on the rockers and shaft, and the roller tip.
The Hotrocker will add lower RPM torque, and higher RPM power to virtually any engine on which it is installed. This is because camshaft selection is a compromise. Ideally, you would have a very mild camshaft at idle and for initial acceleration. However, since it would quickly run out of breath, this couldn't be used for full range driving. Ideally, you would have a very radical camshaft for the highest RPM intended. This would be wise only for race engines only running at high speeds. Therefore, most camshafts are somewhere in between, towards the low end for stock applications, and towards the top end for big engined light chassis autos where the driver can tolerate the loss of low end drivability and engine vacuum.
The Hotrocker requires much less compromise in choosing your camshaft. The simplest formula for choosing your camshaft is to determine what maximum RPM you will be running, and what valve lift (not lobe lift) you need to pull your load to that speed. This valve lift can be a higher number with the Hotrocker than with a higher ratio rocker, since you will be using a much milder valve action at lower RPM. The highest lift will be accomplished by the camshaft lobe lift multiplied by the highest rocker ratio. The same valve lift can be accomplished by a 1.6 ratio with higher lobe lift and by a 1.75 ratio with less lobe lift. Once the top ratio is chosen, three lesser ratios are chosen to be used in the lower ranges down to idle.
Most owners will find that installing the Hotrocker with the camshaft already being used is the best place to start. The valves will be lifted higher than before at higher RPM and about the same as before in position three, and less all the rest of the time.
Valve to piston head clearance, retainer to valve guide clearance, and coil bind are all checked the same way you would if you were installing a higher lift camshaft. In most stock engines, the Hotrocker won't cause clearance problems if moving to a 1.5 to a 1.65:1 ratio or from a 1.6 to a 1.75:1 ratio. If there has been a cam change, other valve train parts need to be checked.
The Hotrocker is currently being sold for street use. Specifically, this version is designed for a maximum lobe lift of .330 with a 1.5 ratio rocker, which gives a valve lift of .495. A 1.6 ratio rocker gives .528, a 1.7 gives .561, and 1.75 gives .577.
Later we will be selling a Hotrocker designed for those who want much larger lifts. This version will have three ratios.
Most engines will need about three eighths inch additional clearance under the valve covers, due to the added height of the adjustment bolts on the pushrod ends of the rockers. Tall valve covers are typically one inch taller than stock, and are well more than tall enough. We are running a Chevy small block with two thick gaskets under each stock valve cover on Vortec heads.
Torque gains coming off idle and in the lower ranges are virtually assured with the gains being greater with more radical cams. The gains in power at the top end will be determined by the ports ability to flow larger amounts of air. Where ports flow only enough air to supply the valve lift given by the cam already installed, going to a higher ratio will give little additional benefit. If a hotter cam were installed in such an engine, little additional high end power would be gained, yet the lower end would suffer. If your ports aren't maxing out with the camshaft you already have installed, then significant gains will be achieved with higher rocker ratios. A published example of the difference that different rocker ratios make is the August 2000 issue of Super Ford, where a Ford Crate 514 with a healthy solid lifter cam produces 626 lbs or torque and 615 hp with a 1.73:1 rockers but, when changed to 1.8:1 rockers, the torque increases 30 to 656, and the hp goes up 20 to 635. A second example is given in the November 1997 issue of Car Craft, where a ZZ4 350 with HOT cam produces 379 hp with 1.5 to 1 rockers, but when changed to 1.6 to 1 roller rockers, produces 394 hp.
This pattern is consistent with each increased ratio, as long as ports can flow the necessary volume.
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