looking for info on my camshaft

[bonvo]

i bought this cam from a fellow ratsuner about 2 years ago and im looking for more info it started life as a l20b cam stamped u20 its supposed to be a regrind and it has this info on the front 

 

 

if its hard to read it says "super BL #1 chambers cams"

 

ive found some info that chambers cams was a company from the middle of the country and im guessing by the lack of info they went under does anyone have more info on this thing? i dont want to go threw all the work to put this thing in to have no gains or possible losses 

[datzenmike]

Measure across the narrow and thew highest point on the lobes and subtract, multiply by 1.5 and that's the lift. Extra lift will add modest gains at top end but drive and idle just fine. Stock L20B lift is 0.413".

[bonvo]

i think im measuring wrong cause i got .285 also not sure how thick the lash pads are compared to stockers 

[bonvo]

when i measured the came lobe then subtracted the lobe circle i got .19 the lash pad thickness is also.19 do i add those 2 together then multiply by 1.5? cause if so the lift is .570

[datzenmike]

Lash pad does not affect lift. You are measuring what the rocker arm 'sees' as the cam turns. The rocker arm has a multiplication ratio of about 1.5 times.

 

 

[bonvo]

Lash pad does not affect lift. You are measuring what the rocker arm 'sees' as the cam turns. The rocker arm has a multiplication ratio of about 1.5 times.

 

 

ok im trying to wrap my head around this if the lash pads dont effect lift what do they effect cause you need t get different lash pads for different cams? am i looking at the pic on the right correctly? cause what im taking from it is that regrinding makes it smaller but raises the lift while doing it 

[Sealik]

when i measured the came lobe then subtracted the lobe circle i got .19 the lash pad thickness is also.19 do i add those 2 together then multiply by 1.5? cause if so the lift is .570

 

Now rotate the cam 90 degrees and measure again

Subtract the 2 measurements from each other and then multiply by 1.48

This will give some indication on lash pads needed

 

Aftermarket lash pads compensate for the re-grind.... but most importantly center the wipe pattern on the rocker

[bonvo]

i did rotate , measure and subtract i got a difference of .19 looks like i need to take the valve cover back off and see what the thickness on the stock lash pads is 

[Sealik]

Here's an example...Shadbolt cam

1.542-1.217 = .325 x 1.48= .481 lift.

Which resulted in .190 lash pads

 

Stock pad on left.....after market on right

 

Oh....and your calipers suck....lol

[datzenmike]

Correct. If you install a reground cam or the valves were done or sunken slightly and just crank the adjustment up to get the proper lash (assuming you can) the cam will actually 'walk' towards the edge of the rocker arm pad.

 

From  http://www.oocities.org/inlinestroker/ near bottom of page.

 

Cam-Lobe Wipe Pattern

Having the correct cam-lobe wipe pattern is extremely important to ensure the longevity of your cam. This is accomplished by using the procedure below.

Coat the contact surface area of the rocker arms with lay-out fluid or black magic marker. Install one rocker arm and set the clearance to the cold specifications. (Intake .008 Exhaust .010) Using the cam sprocket bolt, rotate the cam one complete revolution. Compress the valve spring and remove the rocker, check the wipe pattern to see if it is centered and does not extend off the rocker arm pad. Adjustments are made by using different-thickness lash pads. These are available in 0.010 in. increments and range from 0.150 in. to 0.330 in. Stock lash pads are 0.118 in. (3mm). If the pattern is towards the valve end of the rocker, a thinner lash pad is needed. If the pattern is closer to the pivot end, a thicker lash pad is required. Continue this procedure until all the rockers have been checked. It is not unusual to have as many as five or more different size lash pads to achieve a correct setup.

 

[bonvo]

wait wait wait where do those round things live cause i dont recall seeing them on my motor and i didnt get any with the cam more pics on the way of my measurements 

[Sealik]

Yeah...I don't even bother marking the whole rocker, gets removed anyways.

Leave the center clean and come up about 3/16+ on each edge of the face

 

 

 

[bonvo]

ok here we go 

total lobe height 

1.34

 

lobe center

1.165

 

so

 1.34

-1.165

----------

 0.175

x1.48

----------

0.259

 

thats about half the lift of stock by my math meaning that would make this cam weak anyone seeing an issue with my math?

 

edit i think i see the issue my caliper is in increments of 1/64ths of an inch  not sure if thats standard or not  

[Laecaon]

1.531 / 1.258 = .273  *  1.48  =  .404

 

At least thats what I get off of your measurements.

[MikeRL411]

1.531 / 1.258 = .273  *  1.48  =  .404

 

At least thats what I get off of your measurements.

 

 

Hate to mention this but YOU USE THE OUTSIDE NOT INSIDE marks to measure outside diameter.

[bonvo]

mike your right but at the same time he could also be right my caliper is ancient and reads in 1/64 fractions not decimal places not sure if that has an effect but by eyeballing it the measurements look like they could be right   

[yello620]

mike your right but at the same time he could also be right my caliper is ancient and reads in 1/64 fractions not decimal places not sure if that has an effect but by eyeballing it the measurements look like they could be right   

The fractions are exactly what is affecting your measurements. Regardless of whether you are using the correct line(in/out) on the caliper.

 

Your measurement of 1.34 is actually 1 34/64, or 1.53.  And your measurement of 1.165 is actually 1 16.5/64 or 1.258

See where Laecaon got his numbers from now?

[bonvo]

i do and i figured thats what was throwing it off and his numbers make much more sense then cutting the over all lift of the cam in half i need a new caliper but even with all that aside it has less lift then stock which is the opposite of what im looking for even if it is only an .009 loss lol but that doesnt mean that the duration isnt more then stock how would i measure that? cause im starting to wonder if it has similar specs to the web cams 94a grind 

[Laecaon]

Hate to mention this but YOU USE THE OUTSIDE NOT INSIDE marks to measure outside diameter.

 

OMG its like I dont know how to use a Caliper!

 

And, Hate to mention this,

 

I did use the outside...

 

 

Plus, it doesnt matter which I used, inside or outside, as long as I use the same for both measurements. The difference is what one is after. (I have passed more than enough math and engineering classes to know I am more than confident in what I wrote)

 

So anyways, what measurement did you get?

[banzai510(hainz)]

I can tell thgeat cam isnt huge by the back side(back cam lobe) isnt call all that much

[datzenmike]

Crappy reading caliper may still be .413