Cam questions |
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Cam questions |
ThinAir |
Mar 28 2004, 10:07 PM
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#1
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Best friends Group: Members Posts: 2,553 Joined: 4-February 03 From: Flagstaff, AZ Member No.: 231 Region Association: Southwest Region |
I'm assembling the pieces that I'll need to rebuild my 1973 2.0L engine that will retain the stock FI. I'm wondering about cam choices and why I would want to choose a particular one. The only change I've made from stock at this point is that I've got Mahle Euro pistons & cylinders, but they are stock size so there is no increase in displacement.
I hear a lot about the Web Cam 73 and here's the info I've been able to find on how it compares to stock: Type/Lift/Duration/Duration @ .050 Stock/.392/?/210 73/.426/262/224 Am I correct that Duration is how many degrees both intake and exhaust are open? Or is that called Overlap? If it is called Overlap, does anyone know the specs on the two cams? What is the difference between Duration and Duration @ .050? Lift is pretty obvious - the 73 is going to open farther. I assume this means it can deliver more fuel mixture in the same amount of open time compared to the stock lift. My car is a daily driver that will probably never see anything more exciting than a PCA autocross. So how do I choose a cam and why do I want one or the other? |
lapuwali |
Mar 29 2004, 07:45 PM
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#2
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
Actually, 0.040 is close to 1mm, not 0.1mm. (1mm = 0.039 inches)
I'd like to buy the 0.040 is close to metric theory for non-US cams, except they also all seem to quote lift in inches, too. 0.050 v. 0.040 is just a convention. I'm used to seeing 0.040 on motorcycle cams, for example. My point is that you need to pay attention to that value when comparing cams. I have seen some places quote duration at 1mm, perversely British car places, which are usually selling cams for cars that use inch-dimensioned parts and fasteners (unless they're so old they're using Whitworth). |
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