Monday, February 11, 2019

Life in degrees

Let's start out with the video.

Now a bit more explaining.
There is a facebook group for L Series engine builders, all skill levels, The church of L series.
In that group I posted a pic of the camshaft with way more life and duration than it should have.
A nice back and forth with JeffP and he said I was doing it wrong, and that I needed to measure with the proper lash.
After a few trials and errors, I was able to get the lash dialed in correctly, and it showed that I have been measuring SOHC incorrectly. I did this one with a bit more lash, and it turned out to be a correct cam.
Next time I will be measuring with the cam I plan on running with the proper lash, and adjusting it to see if I can get it closer to a 220/220 but this was a big help in problem solving

Comp Cams 84-131-6:

Everything same as other videos

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. 

Sunday, January 27, 2019

Valve wipe pattern

Here it is finally.

Here is a quick video of my valve wipe pattern.
It was a simple setup, and this was for the camshaft that I plan on running, the
RacerBrown 325-R-108
It does look like it runs a bit off the backside, but it doesn't. Also this was done with zero lash, so when I set the lash to .005 and .007 it will not be as close to the end.
Also note, that the lash caps are being hit in the center, and that is pretty good because they are .175. It was recommended to go with .160 lash caps.

I will do one other camshaft, but I am not sure if I will include the wipe pattern with the next one in the video.