Monday, January 28, 2019

Degree The Camshaft

How to degree a camshaft.
No Idea, but I mostly do it in this video

I found a few things of interest while doing this, the main one was how close this and the Isky L-475 matched up mainly from what I was seeing and from this forum post. Because of that, I never felt out on a limb. I was worried with the initial viewing of the intake opening @.050 being 4* BTDC, but that post made me feel a good deal better about it.
I also did a @.025 measurement to compare it to how much was shaved off, there was .003 removed from it by the machine shop because of uneven wear on the lobes.
I am only right now, while typing this, realizing how useless that was, I do not have a pre-shave base to compare that to, so it really doesn't matter in the big picture.
I feel I should add that I do not think I did the absolute most accurate job with measuring the cam, but I did get it to within 2* overall.
I am currently having an internal debate to see if I want to advance the cam sprocket 4 degrees. A lot of that debate is coming from the summit racing calculator telling me that the camshaft is currently set to -4 advance.
Also notice how when I add 1 degree to the exhaust opening, everything smooths out.
So I will debate if I want to advance the camshaft, or drive it for 1000 miles with it in the stock 1 pin position.

The parts for this are:

  • Camshaft: Nissan Motorsport 99996-E1031 (Racer Brown 325-R-108)
  • Valve Springs: Crane 99884-12
  • Lash Caps: Isky LC-175
  • Retainers: Isky ST1624-12
  • Valves: Stock N47 
Camshaft Specs @.050 
Intake Open 4* BTDC
Intake Close 46* ABDC
Exhaust Open 34* BBDC
Exhaust Close 9* ATDC 

LSA 107 (106.8) 
Duration 230/223
Intake Centerline 111
Exhaust Centerline 102.5
Overlap: 13* 

Intake Max Lift @ valve: .489
Exhaust Max Lift @ valve: .484 

Intake Lift @ Cam: .322 
Exhaust Lift @ Cam: .322 

Calculators Used: 
I used two calculators just to verify my own results. After finishing the video, I also did the math. I used the formulas that are provided by Web Camshaft  

 I should have a camshaft that has a decent power band that starts at around 2800RPM and keeps on till close to 6200RPM.
But there is not a way to be sure yet, I need to get the car on the dyno, so I might be over selling this camshaft. 

And this post is going live a day or two before the youtube video. 

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