Cams, Camshafts, Lift and Duration

[Dool]

I will let the pictures do the Talking ( as if!)

this is the Tec offering,
And this is the Kent/HMC stage 2,
notice the width at the top is greater than the one above so the Rocker/Roller holds the Valve open longer. The longer you hold open the Door the more stuff gets In or Out
There is of course a point at which too much gets in and out .like this one which was in and out no test Ride.

Saving this one for a Boosted Himma
Soon, like why am I so far from the action?. I will have the H-TC with a decomp I expect it will do well and know a perfect Test now, 0 to 100 ! cheaper than a Dyno if you do not get a Ticket for it

But this leads us to that Dreaded Task of "Dialing in the Cam" which is unlike "Plug and Play".
There is a Dowel Pin that locates the Cam sprocket to the Cam as we know, so its Fixed, the Rotor/Flywheel that incorporates the Drive Sprocket is Keyed and also Fixed .
As the distance between the Centers isn't adjustable the Tensioner takes up the Slack of the Chain, which as we know stretches.
So it retards the Cam timing as a result of the Adjustment being done on one side only.
The Chain is can be moved forward or back a tooth/Link which is mostly too much, currently there is nothing I know of that presents as a solution.
Luckily this doesn't matter unless you are chasing the last Horsepower. But Ideally I would like these lines to be a bit closer.
So I need some Offset Dowel Pins .187inch in the 3 or so variations available

 

[sam2019]

the Kent has no decompressor?

 

[Dool]

The only performance Cam available with Decompressor is our H-T C excepting of course the stage 1 from HMC.
For now anyhow

 

[sam2019]

that is a bummer. it also explains why it has more power than the first hitch cam.

 

[Dool]

Stage 2 was a regrind, so extra duration not much just more lift.

 

[sam2019]

Stage 2 was a regrind, so extra duration not possible just more lift.

which is also a miracle to me. if I am not mistaken the cam pushes on the valve so how can taking off material result in more lift?

 

[Dool]

the Base circle was reduced in diameter so overall a greater lift.
The reduction in base circle is why the Decompressor failed on some IMO.

 

[sam2019]

I still dont get it
+ is where the axis runs, how does decreasing the circle do anything to decrease the distance axis - valve?

 

[Dool]

Now you do

The Rocker starts at a lower position ( Tappet adjusters need to take up that distance!) and goes up nearly the same height as the stock so overall greater distance/Lift is achieved.
The top can be ground to increase Duration at the expense of Lift.

 

[sam2019]

Now you do

Not sure.

You are telling me the green distance is relevant whereas I assumed the red distance (being the same in all 3 cases) is relevant. why the green distance?

 

[Dool]

You take the measurements from the center it may look the same but it is the base to the tip minus the base circle.

 

[Dool]

The Centre doesent Vary, but remember you have to adjust the Tappet to get the Rocker to touch the smaller Diamer of the Base,, that is where the Gain is.
Cam lift X 1.185 equals Valve lift because the Rocker is a lop sided See Saw a bit longer on one side.