Is this normal somehow I find it very noisy
Quite normal.
I use the same sc blocks, but in their linger double form. I ordered twice the amount of bearing to fill in the blocks so, i could replace the bearings making the most noise.
Then i lubed my shafts with 3in1 oil. Still produces a but of noise but at the speed we print. Ira not an issue.
You could see ro replace the bearings with igus plastic bearing later…
OK thanks I was also think of putting some oil.
That’s typical for linear bearings like that. If you want quiet IGUS sells a number of bushings that would replace that. Personally love the IGUS on our Lulzbots even if they aren’t implemented properly.
The thing is, usually linear bearings have a load put on them. Once there is some load on them they do tend to quieten down a little bit. This is why I eventually moved onto V-wheel style or at the very least, sliding style bearings like IGUS.
Inside your linear bearing are a bunch of ball bearings arranged in lines from one end to the other. You’re hearing the ball bearings roll on the rod, on the surface of the linear housing, and against each other. If you spin a skateboard or roller blade wheel, you’ll get the same sound. Bearings need the tiniest bit of play so things can roll.
Yes I did see those bearing when I peek into those housing, they are really small 
yes thats the normal noise.
btw if those are not hardened rods like. properly hardened. expect a wear pattern in the rods.
…sounds like you need to lubricate your Johnson Rods with some Silicone Oil to Quiet them Down!!!
Basicly you have two things that generate the noise. One is balls are rolling on the rod and second is balls hit each other. Thus for those type of linear bearing need sticky grease not oil. Keep in mind that chinese bearings are cheaper because they don’t have certain parts in them like ball separators. The balls are just filled in to the channel and nothing separate them from each other. When you move them you hear first the rolling and some clicking noise which indicate the ball hitting each other. try to use silicone grease or any other grease that will not dissolve the plastic housing and you will almost eliminate the noise.
I noticed the same thing on my new Voron CoreXY. The LMUW8s (LM8LUUs) on the Y and Z axis are practically silent, but the LMU8s (LM8UUs) on the X axis sound like something is seriously wrong (i.e. like yours). They’re both brand new Misumi bearings, just different lengths - I have no idea why there’s such a difference.
I added some grease and when everything is up and running the noise level issue is resolved. Thanks for all the help.