Camshaft design

[williamsmotowerx]

Do you have a graph of that latest cams profile acc, vel, and jerk Erland? Plus an overlay of previous cam to this one?

[Erland Cox]

Yes I have but I am new to measuring and looking at them closely I think I have to drive the cam with a motor instead of by hand.
And I have to lubricate more because I get a kink at opening.
I had to put the smoothing to 30 to make it look like something.



Erland

[williamsmotowerx]

That kink is from runout. Are you holding cam in centers?

I use centers (have to with my cam shapes) and zero cam best I can on bearing surface. Then measure cam. I usually get .0005" to 7 runout. I then always zero runout in software after measuring. With 30 smoothing you can't see what's going on with profile.

I turn my cams by hand with Audie setup like you have, no problems

[williamsmotowerx]

Also what side of graph is opening and closing?

[Erland Cox]

It should be from left to right.
I run the cam on the bearings in V blocks in a Camdoctor stand.
I will try the centering, thank you.



I am only using 2 V blocks for the cam.

Erland

[Erland Cox]

Erland

[Erland Cox]

It seems like the cam pro centers itself: http://www.audietech.com/newsletter.html?id=6&task=view

Erland

[williamsmotowerx]

Change your runout to zero. See what happens to the opening ramp.

Or that opening ramp really is like that and no good.

I put a piece of tape on the known opening side of ramp and measure. To see the "bump". My graphs always read right to left.... when I first got my system and measured a bunch of cams... I had to keep it this way. Too hard to go back now.

[Erland Cox]

Don´t you have to rotate the cam backwards to get a rigtht to left graph?

Erland?

[williamsmotowerx]

The rotation is set to CCW when you receive Audie box. To change rotation direction you have to change setting on box, not software.

I had already measured 30 or so cams... when I had a suspicion my graphing was reading right to left. To verify i put a small piece of tape on opening side. Of course you'll see this bump. Yep, all my graphs read right to left now.

I don't know if every box is sent out with a default setting or not. Mine is what it is. I just know I have to read right to left.

If you flip your cam 180 it will read backwards. That's why I suggest the tape trick to verify your graph is actually correct and your hardware is configured to what you want it to be, left to right

[volodkovich]

Erland, it looks like your seating velocity is too high and the valve is beating the seat. You can see the big difference in velocity at the lash point between your two cams. What is the cam velocity at seating? Cam pro plus should even give you a seating velocity in Inchs/sec I believe.

[digger]

The blue one would want tighter lash by looks of it

[Erland Cox]

I will redo all the measurments this weekend and get back.
But yes, I guess that the blue one, CA hast to big seating velicity.
I will see what info I can get from the cam measurment program, it is all new to me.

Erland

[Erland Cox]

I will make a new try at dynotesting to this weekend.
O have gone down in lash, I thougt that it was cold lash but it is hot lash on these cams.
So I will have 0,25mm:s cold, hot lash is 0,30 to 0,35mm.
I have new intake seats with 49mm OD, the stock ones where 46mm as the valves.
But the head hs run very well for 3 years with the previous cam lashed as I lashed the new.
Same brand different ramps.

Erland

[Erland Cox]

And one of my favorite tech writers, Kevin Cameron.

I agree in that.
I think that Kevin Cameron is the best that I have ever read.
A super thread, thank you all for contributing and Hoffman for putting all the artickes together so they can be found easily.

Erland