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Old 10-28-2007, 01:50 PM
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compcams timing card

Im trying to degree the cam on my sbc. The card says when the exhaust opens and when the intake opens, etc. Are those numbers (in degrees) for when the lifter is at .050" lift? Because all of my degrees for when the intake and exhaust opens are around 10-15 degrees off.

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Old 10-28-2007, 04:07 PM
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compcams degee-ing

Yes. those numbers are at .050" lifter rise.
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Old 10-29-2007, 12:16 AM
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did you find true top dead center first? put your piston stop in and turn the engine clockwise untill the piston hits the stop, record the number, turn it counterclockwise untill it stops, the number should be the same, if not adjust untill it is equal on both sides. Also where do you have your indicator measuring off of?
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Old 10-29-2007, 05:53 AM
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That number may or may not be @.05 it will say so on the card. Some cards state both @.05 and @.006 lift numbers. What cam are you using and what numbers are you getting?
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Old 10-29-2007, 10:52 AM
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cam

Yea what enginecar said...

Plus, add the 2 numbers you are getting with your degree wheel +180 and it will equal your duration number @.050 if it does not then the card is giving .006 or something else for valve events.

If you want to know the .050 numbers in degrees take the duration @.050 and divide by 2 then subtract the cam LSA and that will give you the valve open event in degrees. then take that number subtract it from the duration @.050,subtract 180 and that will give you the closing event in degrees...

I will commend you for checking the valve events over just the centerline method.


Keith
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Old 10-29-2007, 03:19 PM
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Quote:
Originally Posted by k-star
Yea what enginecar said...

Plus, add the 2 numbers you are getting with your degree wheel +180 and it will equal your duration number @.050 if it does not then the card is giving .006 or something else for valve events.

If you want to know the .050 numbers in degrees take the duration @.050 and divide by 2 then subtract the cam LSA and that will give you the valve open event in degrees. then take that number subtract it from the duration @.050,subtract 180 and that will give you the closing event in degrees...

I will commend you for checking the valve events over just the centerline method.


Keith

HuH???????????
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Old 10-29-2007, 04:30 PM
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cam

Sorry Mark, i forgot you old guys are hard of hearing..L.O.L.


As an example,,,,Crane cam 967601

The card gives the valve events @.050 1 deg BTDC and 41deg ABDC this cam has a duration of 222 @.050 and a LSA of 110

So if you only had the duration @.050 and the LSA and you wanted to know what the valve events are,,,,you would take the 222 (@.050) divided by 2 = 111 then subtract the 110 LSA = 1 (thats the 1 deg BTDC from the above line) then take the 222 minus 1 = 221 then minus 180 = 41 ( thats the 41 deg ABDC) number from the above line.These are you valve events @.050 for that cam.

Keith ( not a carb guru but knows some cam stuff)
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