Measuring cam lift

[Guest]

Not getting advertised lift on a new set of 370 lift web cams in a 4 valve 1100. Set lash at .005 Tried 2 different dials on top of retainer Best lift so far is .345. So I tried a 380 lift CM G21. On a setup motor light springs .005 lash. Sure enough .350 lift???? Also have a set of CM G3. .345 ad lift. No prob. Got .340 at the retainer. What's up????

[BadBillyB]

Make sure your dial indicator is directly inline with the valve stem. Re-check using zero lash......Billy

[GregT]

Got the right followers ? Have they been reground with the center of the curvature the wrong distance from the pivot center which would change the rocker ratio ?

[4cyl h2]

Just stock good condition rockers (gs1100followers ). Strait lined it best I could with two different dials. Any ideas?? My g3s seemed to measure correct. Didn't measure with 0 lash but 30 - 40 thou off ??????

[trippivot]

with a vernier caliper or micrometer you measure the base circle . then measure the nose of the cam lobe - subtract the two values to attain the cam lift value.

and you do this before you install it into the head so in case you get the wrong camshaft you can send it back -- once installed you own it.

Now can anyone tell the class what the multiplying ratio of stock rockers are so he can determine the total estimated valve lift to avoid coil bind on his valve springs? -

oh yeah 1 more hint = ZERO LASH.

[rapidray]

The GS rocker ratios vary, due to production tolerances, but the COMMON figure is 1.516-1.526.
Ray.

[madmikeracing]

Do what trip says then for true valve lift with that cam multiply result by the rocker ratio ,Think thats how it works HMMMM....Mike

[limeex2]

with a vernier caliper or micrometer you measure the base circle . then measure the nose of the cam lobe - subtract the two values to attain the cam lift value.

and you do this before you install it into the head so in case you get the wrong camshaft you can send it back -- once installed you own it.

Now can anyone tell the class what the multiplying ratio of stock rockers are so he can determine the total estimated valve lift to avoid coil bind on his valve springs? -

oh yeah 1 more hint = ZERO LASH.

c
Can the method of measuring before installing be used to identify a unknown oem camshaft? I have a set of camshafts I saved, but don't why I saved them other than they were being used in my race motor which grenaded 30 years ago and were the best available cams at that time and usable.

[headsbikesmopars]

H2. I use some 'V' blocks to rotate the cams in and a dial indicator zero'd on the base circle. While rotating camshaft and read the lift off the indicator. Use the figure 1.52 to calculate the lift of that camshaft less whatever lash you use. Helps me identify cams using this method .

Terry

[4cyl h2]

H2. I use some 'V' blocks to rotate the cams in and a dial indicator zero'd on the base circle. While rotating camshaft and read the lift off the indicator. Use the figure 1.52 to calculate the lift of that camshaft less whatever lash you use. Helps me identify cams using this method .

Terry

Thanks to all will do some of these ideas