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Old 07-14-2002, 12:46 PM
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Post cam, rockers and general engine questions

I have not worked on engines in about nine years, last time in highschool. I'm in the military and that has prohibitated a lot of my passions. I have a few questions about some engine parts that would be a big help to me. When summit or jegs refers to rocker rollers as 1.5, 1.6, and 1.7 ratio, what does that all mean? Then about pedastal or stud rockes? Screw in or on? How about a solid, roller, and hydraulic cam, whats the real diff in layman's terms? Thanks in advance for all your help. Billybob

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Old 07-14-2002, 02:34 PM
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rocker arms when it is said a rocker is 1.5 this means the ratio of increase added by the rocker for example a cam has a lobe that has .300 lift this is increased by the rocker to .450 because of the fulcrum action of the rocker one side being longer than the other. if the rocker is 1.6 the lift would be .480 but the duration doesen't change because the lifter is still acting as usual and lift is increased by the longer snout on the rocker...pedistals and studs a pedistal is the stud the rocker arm sits on and has a limit meaning they are non adjustable and are torqued to specs(22lbft ect)these are usually used with hydrolic lifters...rocker stud, can be pressed or screwed into the head these are adjustable and are needed when a solid lifter is used but can also be used with hydrolic lifters,chevy big and small blocks use studs when studs are screwed in this means they can't be pulled out by hi lift cams or heavy valves springs, there are also rocker shafts where the rockers sit on a shaft that runs along the head... solid ,hydrolic and roller cams use different types of lifters, solid uses a lifter that is solid with no give they have flat bottoms(cam follower)and have a clearence that must be set with feeler guage to make sure the valve will seat when closed, hydrolic lifters are a shock absorber type lifter that have a spring and piston inside to soften impact on cam and assure the valve will seat, roller lifters are just what they sound like they have a roller on the bottom that follows the cam lobe to reduce friction wear and heat, they can be a hydrolic or solid type
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Old 07-14-2002, 02:58 PM
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So on my 460, if I had a .500/.500 lift for Intake and Ehaust and used a roller rocker with a 1.5 ratio, I'm looking at .750 total lift, way to much for stock heads? Do they sell any smaller ratio roller rockers? Thanks, Billybob
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Old 07-14-2002, 03:01 PM
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On a 69 460 with stock heads, what are the springs rated at for total max lift? Billybob
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Old 07-14-2002, 05:23 PM
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Keep in mind that cam manufacturers figure in the rocker arm ratio when they tell you the cam lift figures... so a 500/500 is 500 at the VALVE, not at the CAM... when calculating this, the cam companies use whatever rocker ratio the engine was stock with... usually 1.5...
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Old 07-14-2002, 05:26 PM
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I dunno about the stock springs... never messed with them... u shud change the springs to whatever the cam company reccomends... only way to break in certain PITA cams... comp for instance...

I think the stock 460 springs shud be good for 450, 500... something in there...
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Old 07-15-2002, 03:34 AM
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hey bildo if you had a cam for a 460 that was 500/500 it would be 500/500 because cam mfgrs advertise cams at valve lift not cam lift but if you used 1.5 rockers the lift would be smaller because 460s use 1.7 rockers
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