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Homemade lo-buck Cam Doctor #3032561
04/11/22 11:09 AM
04/11/22 11:09 AM
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Washington
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hemienvy Offline OP
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With a degree wheel and a notepad, I don't see why you couldn't measure your cam profile yourself.

My only question is what kind of follower would you use ?

It should not matter at all what kind of follower the cam was designed for,
what you are measuring is simply lobe lift at a degree position.

Re: Homemade lo-buck Cam Doctor [Re: hemienvy] #3032564
04/11/22 11:18 AM
04/11/22 11:18 AM
Joined: Dec 2011
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Texas
Chief Offline
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I disagree.. The follower has different contact area which alters where on the lobe you are measuring..
Look at this degree tool kit, specifically the followers. You will see what I'm talking about.

Degree Tool Kit

Dave


Dave Covey
Re: Homemade lo-buck Cam Doctor [Re: Chief] #3032566
04/11/22 11:23 AM
04/11/22 11:23 AM
Joined: Dec 2011
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Texas
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I'll also add your homemade setup will not measure ramp design without a lot of notebook space. Not sure how many calculations it would take to accomplish.

You could get rudimentary numbers, no problem.
It would be nice if it were that simple.

My opinion though..

Dave


Dave Covey
Re: Homemade lo-buck Cam Doctor [Re: Chief] #3032567
04/11/22 11:27 AM
04/11/22 11:27 AM
Joined: Nov 2007
Posts: 21,521
Kirkland, Washington
Pacnorthcuda Offline
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Originally Posted by Chief
I disagree.. The follower has different contact area which alters where on the lobe you are measuring..
Look at this degree tool kit, specifically the followers. You will see what I'm talking about.

Degree Tool Kit

Dave


An issue with flat tappets, yes. Not with rollers.

Re: Homemade lo-buck Cam Doctor [Re: Pacnorthcuda] #3032580
04/11/22 12:14 PM
04/11/22 12:14 PM
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Washington
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hemienvy Offline OP
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Washington
What does the actual Cam Doctor use for a follower ?

I guess I could look that up.

Re: Homemade lo-buck Cam Doctor [Re: Pacnorthcuda] #3032588
04/11/22 12:28 PM
04/11/22 12:28 PM
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Loudoun County, VA
Brad_Haak Offline
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Originally Posted by Pacnorthcuda
Originally Posted by Chief
I disagree.. The follower has different contact area which alters where on the lobe you are measuring..
Look at this degree tool kit, specifically the followers. You will see what I'm talking about.

Degree Tool Kit

Dave


An issue with flat tappets, yes. Not with rollers.

Crane Cams had a tech article on effect on duration w/ increase in roller wheel diameter from standard .750" to .810":

Example from R280/500
.020 = 0.8
.050 = 1.3
.100 = 1.6
.200 = 1.7
.300 = 1.4
.400 = 0.9

Lifter wheel diameter absolutely has an impact on the motion translated at the pushrod.

Re: Homemade lo-buck Cam Doctor [Re: Brad_Haak] #3032589
04/11/22 12:31 PM
04/11/22 12:31 PM
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Washington
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hemienvy Offline OP
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Yes the follower has an impact on valve lift.

I just want to measure lobe lift.

Re: Homemade lo-buck Cam Doctor [Re: hemienvy] #3032601
04/11/22 01:10 PM
04/11/22 01:10 PM
Joined: Oct 2005
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Ontario, Canada
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Stanton Offline
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There is no better fixture than the block itself !!

Re: Homemade lo-buck Cam Doctor [Re: Stanton] #3032611
04/11/22 01:25 PM
04/11/22 01:25 PM
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Washington
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hemienvy Offline OP
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Stanton, my thoughts exactly.

Re: Homemade lo-buck Cam Doctor [Re: hemienvy] #3032627
04/11/22 02:20 PM
04/11/22 02:20 PM
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Washington
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hemienvy Offline OP
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https://www.youtube.com/watch?v=cNy6iK_f0_4

It looks like the machine has a roller follower.

Re: Homemade lo-buck Cam Doctor [Re: hemienvy] #3032631
04/11/22 02:41 PM
04/11/22 02:41 PM
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Washington
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hemienvy Offline OP
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I'm not sure I could measure lobe separation. But maybe.

But measuring one lobe profile should be doable.

Re: Homemade lo-buck Cam Doctor [Re: hemienvy] #3032632
04/11/22 02:57 PM
04/11/22 02:57 PM
Joined: Jan 2003
Posts: 27,961
Irving, TX
feets Offline
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Irving, TX
Originally Posted by hemienvy
I'm not sure I could measure lobe separation. But maybe.

But measuring one lobe profile should be doable.


Measure one lobe then the other. Compare.

If you want the lobe info then measure the lobe directly. Use a small round tip on your dial indicator to minimize angularity error due to contact being slightly off to one side of the tip. Plot the results on graph paper.


We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
Re: Homemade lo-buck Cam Doctor [Re: Pacnorthcuda] #3032677
04/11/22 05:31 PM
04/11/22 05:31 PM
Joined: Jan 2005
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Milwaukee WI
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TRENDZ Offline
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Milwaukee WI
Originally Posted by Pacnorthcuda
Originally Posted by Chief
I disagree.. The follower has different contact area which alters where on the lobe you are measuring..
Look at this degree tool kit, specifically the followers. You will see what I'm talking about.

Degree Tool Kit

Dave


An issue with flat tappets, yes. Not with rollers.


Roller wheel size has a large impact on transferred motion from the lobe. Most lobe catalogs address this.


"use it 'till it breaks, replace as needed"
Re: Homemade lo-buck Cam Doctor [Re: TRENDZ] #3032679
04/11/22 05:36 PM
04/11/22 05:36 PM
Joined: Mar 2006
Posts: 9,048
MI, usa
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If you use the block, cam, and tappet that you will be using, you can measure pretty close to anything you want. Bonus if your lifter bores are not true you will see exactly what dimensions the engine is running at.
Doug

Re: Homemade lo-buck Cam Doctor [Re: hemienvy] #3033108
04/13/22 11:39 AM
04/13/22 11:39 AM
Joined: May 2008
Posts: 5,343
Aurora, Colorado
451Mopar Offline
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Done it using the block and lifters, and manually recording Intake and exhaust lift every degree for 720 degrees, or 1440 data points. Pretty time consuming.
I though about building a rotary encoder type degree wheel and using two indicators with the data outputs for each lobe measurement, and have all the data logged into a computer which would record each lobe lift for each increment of the encoder output.







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