Opinions on this engine machine work.

I came here thinking "I don't know enough about machine work to have a valuable opinion, but maybe I'll learn something." 

I was wrong. 😬

Nockenwelle said:

 

This looks like the quality of machine work that prevented our company from being able to be profitable in the face of the clientele who remembered that 30 years earlier NAPA would bore a block for $10 a hole. 

I don't mean the deck surface finish, that's easy with the right tooling and a good block machining center.  (Which costs money - ours was almost a million dollars for a demo model) I mean the time consuming attention to detail.  All edges have been deburred, everywhere.  Water jackets, block surface edges, not just on the deck but on the front and valley too.  All bolt holes have been given a light countersink.  Block is spotlessly clean.

You can do this kind of work if you charge for it, or pay yourself $5 an hour and work 16 hour days.

I machined a BMW 2002 block and head on a big surface grinder.  Both had a better than 16 finish, similar to Nockenwelle's; when I showed my friend that had a foreign car shop he said "Too shiny, no tooth for the gasket".   I went back and did it with a milling machine for a 125 finish, worked fine.  I understand the gasket can move around with super smooth surfaces.

YMMV.

With modern gasket technology, the gasket is supposed to be able to move around, within constraints.  It's weird to think about a gasket like that but this has been known since Ancient Times when manifolds were held down with long bolts and T shaped washers.  The head will get hotter than the block so it has to be able to expand and contract without damaging the gasket.  Used to be that head gaskets failed with regularity, because the head runs hotter than the block and eventually the gasket gives up, or got crushed over time from the super short head bolts.  Now we have slippery gaskets, that can even slide around internally with multiple layers, and extra long head bolts so the torque stays fairly consistent as the head moves side to side or whatever.

The more I learn about gaskets, the more I understand why they call them "sealing systems".

I really like watching Engine Power on Power Nation TV. Their attention to detail is great, not that I would ever consider assembling a motor, which would be with Plastigauge. And maybe also a torque wrench if I ever get around to buying one.

https://www.powernationtv.com/shows/engine-power

This is educational to me.  The last engine I built was a BBC 454.  The deck got hit with a scotchbrite wheel on a drill, wiped down with brake cleaner, and a new gasket installed.  Still going 40k later.