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/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> How do I tell which cam is which? /cgi-bin/YaBB.pl?num=1507879403 Message started by mpescatori on 10/13/17 at 00:23:23 |
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Title: How do I tell which cam is which? Post by mpescatori on 10/13/17 at 00:23:23 Hi all, through the years I have bought a few cams from lancer, and currently ride the Stage2 cam. The OEM cam was nice and sweet down low but not very quick. The Stage 2 cam is nice and quick in the high rpm range but commuting in stop&go traffic the engine becomes lumpy and won't go much below 3000rpm (I have a tach) Then I bought a Stage 3 cam which is supposed to have all the lift of a Stage 2 plus the nice round mellow phase of the OEM cam. BUT I have the OEM and Stage 3 in one box and would like to know how to tell them one from the other. ::) Use a micrometer and measure the lobes? ::) |
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Title: Re: How do I tell which cam is which? Post by Ruttly on 10/13/17 at 03:33:47 Yes , larger/taller lobes have more lift would be the performance cam. |
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Title: Re: How do I tell which cam is which? Post by Dave on 10/13/17 at 05:17:23 The Stock and Stage 1 cam will have the lowest Lift.....the Stage 2 cam has a higher lift and longer duration. So......the cam with the thickest lobes will be the Stage 2 cam, and the Stage 2 will have the largest angle between lobes and likely have a broader width at the top of the lobes. It might be hard to tell which is which if you don't have them side by side to compare....and it may even be a bit technical to tell if you do have them side by side. |
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Title: Re: How do I tell which cam is which? Post by justin_o_guy2 on 10/13/17 at 08:45:23 Dial calipers might help. Maybe roll them across a layer of Play Doh,, |
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Title: Re: How do I tell which cam is which? Post by verslagen1 on 10/13/17 at 09:04:08 7A77787573642421160 wrote:
Tip: To quickly find maximum lobe lift, measure the base circle of the cam and subtract it from the thickness across the cam lobe's highest point (see the diagram below). Tip: Maximum valve lift can be calculated by multiplying the maximum lobe lift times the rocker ratio. |
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Title: Re: How do I tell which cam is which? Post by batman on 10/13/17 at 09:40:30 I may be all wet here ,but here goes! the high performance cam being made from our cores may be ground more on the broader base (rounded) end of the lobe to achieve it's higher lift .(The distance from the center of the cam shaft to the base subtracted from the distance from the center of the shaft to the pointed end of the cam lobe being the total lift)therefore if you measure the distance of the entire lobe the one that measures the shortest might be the performance cam. If the cams are welded up and completely reground this still may be true,if not than I am full of it and subject to tasting crow . |
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Title: Re: How do I tell which cam is which? Post by Ruttly on 10/13/17 at 10:18:54 So , How do you like your crow prepared ? ;D |
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Title: Re: How do I tell which cam is which? Post by justin_o_guy2 on 10/13/17 at 11:03:42 As long as the grinding removes material equally around the base, the lifter would track closer to cam center down there, allowing the lump to create the lift. |
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Title: Re: How do I tell which cam is which? Post by batman on 10/13/17 at 16:52:12 Ruttly,I like my crow well done,thank you! JOG ,if more was ground off at the center and less at the sides of the base then this could increase duration.(were the heck did I put those files? ::)) |
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Title: Re: How do I tell which cam is which? Post by justin_o_guy2 on 10/13/17 at 17:12:24 You don't want a valve cracking open until the cam is further around. To get what you want doing it that way would take a complete analysis of the valve train. If you're trying to affect the valves, best to play with the lobes, The lift would be increased by cutting the circle down that the lobe Grows up out of. By whatever the ratio of lifter movement to valve actuation is. |
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Title: Re: How do I tell which cam is which? Post by batman on 10/13/17 at 20:00:49 Jog ,I was lust kidding about the files ,I think the best way to go is to buy a cam if looking for more performance. |
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Title: Re: How do I tell which cam is which? Post by justin_o_guy2 on 10/13/17 at 20:29:08 Way too hard for files.. |
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Title: Re: How do I tell which cam is which? Post by Ruttly on 10/13/17 at 22:56:57 Ok , a reground cam like our aftermarket cams,are ground down rewelded all the way around then ground to the new specs. Sometimes you can see the layer on the sides of the lobes. Cam lobe has a base circle , 2 ramps , 2 flanks and the nose Base circle the round area where there rocker arms have clearances to the cam,base circle should always remain the same diameter Ramps are the area that opens & closes the valve,moving the ramps changes when valves open & close,duration Flanks area between ramps & nose Nose is what determines amount of lift Overlap,lobe separation,lobe centers,advance,retard is where it gets very complicated :-/ |
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Title: Re: How do I tell which cam is which? Post by verslagen1 on 10/13/17 at 23:24:32 complicated? :-? I'm sure you can work it out. ;) |
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Title: Re: How do I tell which cam is which? Post by Dave on 10/14/17 at 04:36:49 I just compared a stock cam to a Stage 3 Webcam. The distance from the bottom of the cam circle to the bearing has the same distance on both cams - so they have not just ground more material off the bottom of the cam profile - they have welded and reground the cam to make the new profile. You should be able to visually observe the difference in the cam lobe profile. Hold the cam with the gear end away from you, and sight down the length of the cam with the lobe on top. The Webcam has a very round top of the lobe - it opens the valve and sets it back down at what looks like the same rate. The stock cam has a very rounded look on the left side of the lobe (that is the side that lifts the valve off the seat) - the right side of the cam lobe has a much sharper curve - so it begins to drop the valve down at a faster rate. The curve and slope of the lobe is not symmetrical on both sides where maximum lift occurs. So.....if the lobe appears the same on both sides - it is likely the Webcam. If the lobe appears a bit different on both sides - it is likely the stock cam. The height of the lobe above the bearing surface is also larger on the Webcam (more lift). |
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Title: Re: How do I tell which cam is which? Post by Ruttly on 10/14/17 at 10:31:38 Yes Batman I wouldn't serve you undercooked crow. Ya know the crow was considered to be "the bringer of death" , as the plague went thru Europe the only thing else that died was crows and they assumed that the crow was a carrier of the plague. Maybe some garlic grub gravy on your crow , yummy. |
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Title: Re: How do I tell which cam is which? Post by batman on 10/14/17 at 20:55:41 Crow it is, but I'm not doing left overs! |
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Title: Re: How do I tell which cam is which? Post by LANCER on 10/15/17 at 01:50:57 Ya'll are just sick sick sick. |
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Title: Re: How do I tell which cam is which? Post by mpescatori on 10/16/17 at 01:05:57 Naaah... just hungry. And maybe watched "The Lone Ranger" a few times too many. Thank you Dave for your explanation, it's the kind of tip I needed. |
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