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Need Cam Selection Help |
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Javelin Dan
AMC Apprentice Joined: Aug/02/2014 Location: Akron, OH. Status: Offline Points: 53 |
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Posted: May/07/2021 at 9:56pm |
Hi folks, long time, no talk. I posted here years ago about my proposed project and while life got in the way along the way (lost two parents, two parents-in-law, and remodeled most of the entire house), I am now finally ready to move forward and screw my motor together. Let me briefly update you on the scope… I own a 1969 Javelin with the original 232. That motor has been warmed over with a cam, headers, intake, carb, and ignition, but is now getting a little tired and never made a huge amount of steam anyway with it’s 8 point-something:1 compression. The “new” motor will be a 258 out of a ‘73 Comanche. This has been bored .040 over and fitted with Sealed Power hypereutectic pistons for a Chevy 305 (this process was started before they made dedicated pistons for the AMC motors). The machinist figured this would provide between 9:1 and 9.25:1 compression. The head is a new complete 4 liter HO unit from Clearwater Cylinder Heads, drilled for the ½” bolts and with the outboard water passages welded. It has springs installed to support .500” of lift. I have intake, headers, and ignition all covered. The transmission will be a GM 200-R4 used with a Novak adapter. Rear end is Corporate 20 unit from a ‘68 AMX with 352:1 gears. Torque converter will be something around 2000 – 2200 RPM stall. My question here is mainly about the cam. At the time I was vigorously acquiring parts, I secured a Comp Cams 262H-11 “Extreme Energy” cam. The specs at .050”are: Intake - .493 lift and 218 duration, and exhaust: .512 lift and 226 duration, and an LSA of 111 degrees. Along the way, my ADD set in and I started chasing the “Holy Grail” of camshafts looking to see if there was one that would be significantly better. I THOUGHT I had decided on a Lunati Voodoo cam of somewhat similar specs because I had always heard good things about them and that they produced more torque under the curve. When I called Lunati, I talked to a guy who must have been having a bad day and kinda treated me like I had just run over his dog. He wasn’t REAL forthcoming with information on comparing his cams to others, but when I mentioned the cam I have he told me that if I used it, he could guarantee excessive valve train noise with the Comp grind. Now I’m confused and hesitant about the camshaft selection. Is the Comp cam I’ve already got plenty good enough, or is there a better choice? Fire away! |
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mixed up
AMC Addicted Joined: Jun/16/2015 Location: Monroe mich Status: Offline Points: 2178 |
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with the jeep crowed having a lot of 6cyl information you might want to look at a jeep forum also for information on your mods and cam lunati use a softer ramp up for there lift so it not so hard on valve spring is what he might be referring to and he said that about other cam because of the profile on other cams ae aggressive in nature causing valve train noise I'm sure yours would be fine
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69 amx 290 auto
65 220 290 4spd 80 ford fairmont |
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Javelin Dan
AMC Apprentice Joined: Aug/02/2014 Location: Akron, OH. Status: Offline Points: 53 |
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Yes. In the interest of brevity, I didn't go into my choices or why I chose them. The whole concept behind the "High Energy" series was aggressive ramp profiles: fast opening and fast closing which effectively keeps the valves open longer. This is supposed to provide for more low end torque - or at least that's what Comp claimed at the time I bought it. Reading between the lines of what precious little Lunati-guy told me, I got the impression that their ramp profile opens quickly also, but shuts down more slowly to reduce valve noise. What noise? Would there be a valve clatter like a dieseling effect or something different?
I also didn't mention what I want from the cam. I only want what every other 69-year-old-going-on-16-year-old wants; decent low end, strong mid-range, and an aggressive sounding idle. Not looking to rev it much past 5 grand. I was hoping Frank Swigert (if he's still here) or other like minded 6 cylinder gurus could weigh in and give me an ear-full. Anyone have experience with this cam or others they have had good success with on the street? As hokey as they are, if Comp had a "Thumper" cam for this motor, the 16-year-old in me would be punching the "BUY" button right now...
Edited by Javelin Dan - May/08/2021 at 7:55am |
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Sonic Silver
Supporter of TheAMCForum Joined: Nov/23/2011 Location: East Tennessee Status: Offline Points: 7966 |
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Javelin Dan
AMC Apprentice Joined: Aug/02/2014 Location: Akron, OH. Status: Offline Points: 53 |
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Thanks Sonic Silver! Very enlightening indeed...
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Sonic Silver
Supporter of TheAMCForum Joined: Nov/23/2011 Location: East Tennessee Status: Offline Points: 7966 |
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Also, google "47.5% rule on camshafts." That is based on Chevrolet with 1.5 rocker ratio, and I'm not sure if that also applies to AMC. The rule pertains to the duration at .050 being divided by the lift with 1.5 rockers, and resulting valvetrain noise and durability.
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Heavy 488
AMC Addicted Joined: Apr/27/2019 Location: In the Status: Offline Points: 3557 |
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Pick your favorite can maker. Call them, describe what you want and have it made.
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Sonic Silver
Supporter of TheAMCForum Joined: Nov/23/2011 Location: East Tennessee Status: Offline Points: 7966 |
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