A little help, or clarification with the Balance shaft assembly

Good Day All,
Pretty sure this is my first post here. I have had a 2013 Speed3 since about 2017.
it is the Daily Driver with a few upgrades.
My concern right now is the balance assembly.
I have it out and all the shims are on their feet so that is good. and I plan to put it back, because DD not RC.
I looked at the assembly and in the block, and I can't see an O-ring or other sealing device for the oil feed into the balance shaft assembly.
I have looked at the engine work shop manual L3 with TC, and there is no indication of a seal.

Is a seal required for this?
If so I can't seem to find the old one.
If not, why not?

Thanks for your time and attention

 

Lots of views and no replies.
I did check this out, it is an online Mazda parts manual. Doesn't show a seal.

 

Browsing around the internet/youtube and I cant find a tear-down video, or a balance shaft for sale that has an o-ring.

 

Same here. Dynotronics says there is one, but I can't find it anywhere.

 

I have no idea but if Mazda doesn't have a part number then I wouldn't think there is one. Is there a groove on either side to install an oring on? It would just go between the faces of the two parts that would be a gasket

 

I messaged the guy building my motor. No seal. Fits like a dowel.

 

Also the torque sequence reads strange. It's a 2 step torque sequence, no angle. Make sure it's timed properly, will need TDC tool. If the shims were not moved around, no need to measure backlash, there's no reason for it to have changed. If unsure, then definitely need to measure it. 25NM (19ft lbs) first, then do the bolts up again to 45NM (33ft lbs)

 

There is no grove and the "Tube" on the Balance shaft assembly is very tight in the hole in the block, not that it is hard to get in but that it has to line up perfectly and there doesn't seem to be a gap.
If an O-ring or Gasket goes there it will make between the machined surface of the block and the machined surface of the Assembly, no room to fit in the hole.

 

Thank you sir.
and for the additional information. I do have the TDC tool and the manual

Thanks everyone for checking it out. it just seemed to me that something that gets pressurized oil wound have a seal.