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Cam degreeing with head off?
Posted: February 21st, 2009, 5:47 pm
by SilverXJ
I am wanting to degree my cam.. I just plan on installing it straight up and want to check it to make sure it is that... heck my timing set is adjustable, might as well use it if necessary. I have the finding TDC part down pretty good. However I don't know the best way to get the dial indicator on the cam and accurately measure IVC and IVO. I'm going to be using a 11" degree wheel (machinist won't let me borrow his big ass 3' one.. seriously he has one that is 3' in diameter). Suggestions?
I thought about cutting down an old pushrod and JB Welding it in an old lifter. However one thing that worries me is that I need to get the push rod 100% perfectly straight in the lifter. The second thing is using the old lifter on the new cam even though it isn't under a lot of pressure. One thought it putting a piece of soft material on the bottom of the lifter, like plexi or derlin and then cutting the lifter at a 90* and then putting it together like that. I just don't want the push rod to move off parallel.
Re: Cam degreeing with head off?
Posted: February 21st, 2009, 6:06 pm
by dwg86
If you put your dail indicator tip in the pushrod hole, it should hold it straight.
Re: Cam degreeing with head off?
Posted: February 21st, 2009, 6:44 pm
by SIXPAK
That is the way I do it also. Works fine for me.
Re: Cam degreeing with head off?
Posted: February 21st, 2009, 6:51 pm
by SilverXJ
Will do!
Once again i was over thinking things.
Re: Cam degreeing with head off?
Posted: February 22nd, 2009, 11:10 am
by SilverXJ
What size would you recommend? I am looking at an 18" one, or would I be able to get away with a smaller one?
Re: Cam degreeing with head off?
Posted: February 22nd, 2009, 5:25 pm
by SilverXJ
I got the 18" one... it was the largest I could get without going over $100. I found it cheapest through Amazon for around $48, which had free shipping. The larger the wheel is the easier it is to read and more precise you can get.
Re: Cam degreeing with head off?
Posted: March 12th, 2009, 7:54 pm
by SilverXJ
I've read over several guided on how to degree a cam. However, they all mention having the timing events at the lifter... however my cam card only lists timing events at the valve.. or the values on my cam card really at the lifter? If they are indeed at the valve only, then how do I degree with the head off?
Re: Cam degreeing with head off?
Posted: March 12th, 2009, 8:28 pm
by amcinstaller
would you mind if a interrupted with a small question?? if it needs to be moved out, do so or i can start a new topic if need be.
what is the purpose of degreeing a cam? is it similar to gettin the cam in the right position for timing, or is it somethin else altogether? ive been hearing about this more and more, and im just not entirely sure what its all about.
Re: Cam degreeing with head off?
Posted: March 13th, 2009, 6:17 am
by SilverXJ
Sometimes the cam isn't made 100% straight up, or the timing set could be off, or the keyway in the crank. Its to verify that it is installed straight up (no retard or advance), or retarded/advanced depending on what you want.
My concern with degreeing with the head off is that the IVC, IVO are measured at .050" at the valve.. or that is at least how I interpreted it, which won't be the same at the cam.
Re: Cam degreeing with head off?
Posted: March 13th, 2009, 6:55 am
by yuppiexj
SilverXJ wrote:My concern with degreeing with the head off is that the IVC, IVO are measured at .050" at the valve.. or that is at least how I interpreted it, which won't be the same at the cam.
My understanding was the .050 was lifter rise from the base circle.
it's alluded to here
http://www.compcams.com/Technical/TimingTutorial/
If I am wrong someone smack me around and set me straight.
Re: Cam degreeing with head off?
Posted: March 13th, 2009, 7:05 am
by SilverXJ
I see where they say its the lobe lift in that pdf. Then they say it will be .075" at the valve with a 1.5 rocker. However they then tell you, in this file:
http://www.compcams.com/Technical/Instr ... es/145.pdf (page 10, step 10), to position the dial indicator on the valve retainer and read the degree at .050" valve lift.
I am thoroughly confused.
Re: Cam degreeing with head off?
Posted: March 17th, 2009, 7:09 pm
by SilverXJ
I was over thinking this. Its very easy to do. See my build thread in projects. Measured IVC, IVO, EVO, EVC, and center line.