Measuring cam lobe lift
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Member
Joined: Jul 1999
Posts: 347
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From: Marshall,IL
Car: 82 & 91 Firebird
Engine: 400 & 355
Transmission: TH350 & 700
Axle/Gears: 4:11 & 2.72
Measuring cam lobe lift
How do you measure cam lift, off just having the cam by its self?
Thanks
John
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82 Firebird,408,Dart Iron Eagle 215's,Cam 229/239, .498/.520,TH350 Tranny, 750 Speed Demon carb, Hooker Headers(I.E. POS) Manual steering, Bfg DR's.
Check out my birds new home.
Best et 8.21 @84mph in the 1/8th
Thanks
John
------------------
82 Firebird,408,Dart Iron Eagle 215's,Cam 229/239, .498/.520,TH350 Tranny, 750 Speed Demon carb, Hooker Headers(I.E. POS) Manual steering, Bfg DR's.
Check out my birds new home.
Best et 8.21 @84mph in the 1/8th
Supreme Member
Joined: Jul 1999
Posts: 1,294
Likes: 1
From: was: Palmdale, Ca
Car: was: 1984 Camaro Z28
Engine: was: L69
Transmission: was: 700-R4
If the cam is not installed, it is easier. Measure the cam's base circle diameter and subtract this amount from the cam's lobe height, that gives you the cam lift. The way I do it is: get a dial caliper (vernier) and measure the lobe, while turning the cam, untill you get the smallest reading. Mark it down. Repeat the previous step, but this time look for the largest reading. Subtract the small from the large and your done. On a roller it's easy because you don't have to worry about the tappered edge and giving you different readings, unlike a flat tappet which could. In this case I use the larger side of the lobe (doesn't matter, but besure to use the same side. Other wise you'll get incorrect values), it's toward the distributor gear, it makes it easy and consistent. HTH 
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George P. Lara
1984 Z28
2001 SS Coming Soon
SCCA, SCFB, SC3GFB
[This message has been edited by MRZ28HO (edited June 29, 2001).]
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George P. Lara
1984 Z28
2001 SS Coming Soon
SCCA, SCFB, SC3GFB
[This message has been edited by MRZ28HO (edited June 29, 2001).]
Member
Joined: May 2001
Posts: 137
Likes: 1
From: Atlanta, Ga,USA
Car: 1992 RS
Engine: 305
Transmission: 700R-4 when it works
i would recommend sitting the cam on V-blocks on the first and last journal. then use a dial indicator. find zero on the base circle then rotate the cam to the max lift and simply read the dial. This will be more acurate than calipers on a flat tappet because it guarentees that you will not be measuring the opening/closing ramps.
Also when looking down at the cam, allow the dial indicator probe to ride along the part of the lobe that is closest to the distributor gear. The lobes (on a flat tappet cam) are cut at a very slight angle to allow the lifters to keep the cam in proper postion. a roller cam does not have this condition.
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LOBC-- SS-84
92 RS Heritage package with a 305
84 El camino
Also when looking down at the cam, allow the dial indicator probe to ride along the part of the lobe that is closest to the distributor gear. The lobes (on a flat tappet cam) are cut at a very slight angle to allow the lifters to keep the cam in proper postion. a roller cam does not have this condition.
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LOBC-- SS-84
92 RS Heritage package with a 305
84 El camino
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