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How to measure lift on cam ?

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Old 05-21-2011, 03:19 PM
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Question How to measure lift on cam ?

Does anyone knows how to measure the lift on a cam for lt1 ?

I dont know the cam specs on my car , I need to measure lift , in order to install springs that match !!

I googled it and got little confused.
Old 05-21-2011, 03:50 PM
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Do you have a set of dial calipers? If so, measure from bottom of base circle to the top of the lobe, then measure the base circle width. Subtract your base circle measurement from your overall lobe measurement and it will give you lift. Hope this helps.
Old 05-21-2011, 04:15 PM
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If the cam is in the car install a lifter and use a dial indicator to measure lift. Note that you must make sure the lifter follows the cam and doesn't stick in the upward position even though at that point you should have the lobe lift. Then multiply by the rocker ratio.
Old 05-21-2011, 04:22 PM
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Originally Posted by vettenuts
If the cam is in the car install a lifter and use a dial indicator to measure lift. Note that you must make sure the lifter follows the cam and doesn't stick in the upward position even though at that point you should have the lobe lift. Then multiply by the rocker ratio.
That too, except if you're looking for just cam lift, which seems to be what he is looking for, leave the rocker ratio out of it.
Old 05-21-2011, 05:37 PM
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Originally Posted by LSn00b
Do you have a set of dial calipers? If so, measure from bottom of base circle to the top of the lobe, then measure the base circle width. Subtract your base circle measurement from your overall lobe measurement and it will give you lift. Hope this helps.
why not multiplying by rocker ratio ? keep in mind i need to know the lift to install new set of springs.


Originally Posted by vettenuts
If the cam is in the car install a lifter and use a dial indicator to measure lift. Note that you must make sure the lifter follows the cam and doesn't stick in the upward position even though at that point you should have the lobe lift. Then multiply by the rocker ratio.
sound good if i can make it while the cam is in the car , but what do u mean by installing a lifter ? and where ?
Old 05-21-2011, 08:33 PM
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Originally Posted by Mohammed
why not multiplying by rocker ratio ? keep in mind i need to know the lift to install new set of springs.




sound good if i can make it while the cam is in the car , but what do u mean by installing a lifter ? and where ?
You never specified lobe lift or valve lift in the original post.
Old 05-21-2011, 08:41 PM
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Knowing the lift isnt a bad idea, but theres a lot more to gettin the right springs than matching the lift.
Old 05-22-2011, 02:37 PM
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Originally Posted by LSn00b
You never specified lobe lift or valve lift in the original post.
so which one needs multiply the rocker ratio ? lobe or valve ?
Old 05-22-2011, 05:44 PM
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You multiply the lobe lift times the rocker ratio to determine how much the valve will move. What I meant with the lifter is you need something that moves with the cam for the measurement. Usually the lifter is the best method to do this. The dial indicator would be very hard to set up to measure directly from the cam.

Do you know what cam is installed in the car?
Old 05-23-2011, 01:58 AM
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Do you know what cam is installed in the car?
No , I guess if I wasn't lucky to know the lift, I'll change the damn cam and make life easier.
Old 05-23-2011, 04:18 AM
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One other option, since you are planning to change springs, get a set of light check springs and install them. Then roll the motor over by hand with a dial indicator on the valve spring retainer. You can get your lift that way as well if you have the tools. While check springs are available from Summit or other parts places, they are no more then just very light springs around the same diameter as a valve spring. Since your location may cause delays in obtaining a set, you might be able to look local for springs that will do the job.



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