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Camshaft Lobe Width? |
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6881 |
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Posted: Feb/11/2019 at 7:23pm |
So just bought and returned a Comp Cam camshaft. It had lobes anywhere from 0.0406" to 0.460" wide.
I have 2x original AMC camshafts and they are both 0.500" to 0.508" lobe widths. In fact I remember all being at or near 0.500" lobe width. Bought Comp before with 0.485" + lobe width. Who sells AMC camshafts with factory spec lobe widths? I have not found it in a search, and the manufacturers don't seem to advertise it. Duration, lift, separation ... are second priority to me as far as an engine build. Not a straight out performance builder, street power and longevity. Won't use aluminum roller rockers as their fatigue life cycle is 30,000 to 40,000 miles - 100,000 miles is the goal.
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MattsGarage
AMC Apprentice Joined: Jan/24/2019 Location: El Paso TX Status: Offline Points: 95 |
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I have a howards hydraulic flat tappet here. Measures .503 to .509. I just put a howards solid flat tappet in the new engine, and it degreed in near perfect.
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6881 |
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Thanks, Howard's it is.
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MattsGarage
AMC Apprentice Joined: Jan/24/2019 Location: El Paso TX Status: Offline Points: 95 |
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Another thing to note on howards, their lifters are the correct diameter.
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Greyhounds_AMX
AMC Addicted Joined: Nov/14/2009 Location: Kansas City Status: Offline Points: 1268 |
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This is really interesting.
I wonder how wide Bullet lobes are.
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1968 AMX 390 w/T5
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6881 |
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Yes it is. Took a 360 apart a few years ago with an aftermarket cam with 0.430" lobes. The lifters and cam were shot. Cam was working the edge (rounding) into some of the lifters. 0.055" and the cam would have been near the lifter edge and likely everything would have been good.
On the pressure side of things, after many miles the cam/lifter contact area of the old AMC cams was about 0.250" and the top of the lobe 95% to 100%. I would assume the less surface area you have the higher the pressure, at least that is the math I learned. I believe AMC knew what they were doing when they designed the lobe width.
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imacarfan2
AMC Addicted Joined: Jul/01/2007 Location: Northeastern MA Status: Offline Points: 971 |
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I just measured two cams for their lobe with. I only did one or two lobes on each and will check them all later. The cams were both older cams; one an Edelbrock Performer and the other the small Summit cam (K8600). All the lobes I measured were a hair over .500, maybe 17/32nds which is about .531, but maybe not even that much. My measuring device is in sad shape, so readings should be taken with a grain of salt. They are definitely over .500, though.
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67 Ambo conv
68 AMX 68 Ambo 4 door 70 Ambo 4 door (2) 71 Hornets (1 SC/360) 73 Hornet 2 door 77 Matador coupe 77 Sportabout 78 Concord 2 door 81 Concord wagon |
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a401classic
AMC Apprentice Joined: May/02/2008 Location: GA Status: Offline Points: 98 |
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My Comp Cams custom hydraulic roller cam has 0.570" wide lobes, wider at the base circle.
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'64 Rambler Classic 770 2DR
Twin Turbo 423.7 AMC (short block done) TH400 / GV |
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6881 |
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So, looking at the Howard's cams and doing a little playing.
The 310021-14, 277 duration, intake and exhaust; 0.480" lift - fine for bridge rockers; 223 @ 0.050, not overly aggressive lift - fine for bridge rockers. 114 LS and 110 ISL. This is tame, but advancing this to 106 ISL puts dynamic compression at 7.9:1 on a 401 with the Wiseco 9.5:1 forged pistons, by my calculations. This looks more appealing of the Howard's product line for street use, pump gas (93) and standard transmission. Expert thoughts? Are my calculations close? |
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MattsGarage
AMC Apprentice Joined: Jan/24/2019 Location: El Paso TX Status: Offline Points: 95 |
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Have you ever heard of Mike Jones? He has an online cam recommendation form at Jones racing cams. The response you get is directly from him. And there's a spot to put comments also as for your durability concerns. It asks for a lot of info but imo it's well worth the time as he is really good at what he does.
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