Hi KK!
Well, I'm back. Civic duties can sometimes really cramp my style but somebody has to do some.
Now, where were we? oh yes, the cylinder heads. Nope, on some 2 strokes with no valves & thus valve seats but never on a 4 stroke. It just behoves me how they would install & grind valve seats from the bottom end. I know the huns could get real complicated but this is a mind bend. I've worked on Audi & VW for the past 7 years & talk about overkill. None of my books show about the headless DBs so I went OL but still nothing. Differences in CRs from bank to bank was another surprise to me. I'm starting to think I know next to nothing about these crates. They fly in the face of conventional wisdom, IMO.

Darn, another call & another all nighter.

FWIW,
Good Hunting!

check out this link Kraut, http://allaircraftarcade.com/forum/viewtopic.php?t=17837&sid=140b2a9f8839369880b71ef042f0bf4b

Notice the valves look to be vertical.

It's me again KK!
Thanks for the pics. How do you find all these gems?
Now I 'think' I can see how it's done. The cyclinder is short so when it's unbolted from the crankcase, the distance from the cyl. base to the where the valve seats are, is not all that long. Overhead valves inserted from the bottom & then locked in from the top as per conventional ways. But, the machining for a wartime piece of equipment, ala like their tank engines, makes little sense. All that for how long a life expectancy in combat?
This screww adjustment you mentioned above reminds me of an adjustment for enrichening or leaning fuel injection on early diesel engines.
When an aero engine from that area was on put onto WEP, a rich condition was in place. In fact, that one 109 take off above clearly shows the DB smoke trail when on T.O. Power. If it smokes that much @ low alts, it must of really smoked @ the higher ups. As I mentioned above, some pilots said & wrote, they thought it was damaged & heading out of the fight. Also, the Allied pilots knew which runway was used by the 262s by the scorch marks from their engines on take off. Those scorch marks I bet were from heat & carbon, ie. fire und smoke.
As far as the Octane for when & where is still all over the boards. I learned back in my discussions/arguments in Air Warrior & Warbird days that to read one set of 'facts' may & do, some times contradict another set of 'facts'.
Through all this, I have learned a lot about the DB engines & I thank you for that. I'd really like to touch one, & maybe give it a small kiss. No, the DB Engine!!!!!!!Now, what's left, oh, the BMW radials & Junker inlines. OUCH! Anyways, I need some rest now as I've been working with some addicts in recovery & some times they don't keep regular hours.

FWIW,
Good Hunting!

For the last link, Google image search.

Yes I have read also that the large quantity of black smoke produced from working the throttle was used as an escape tactic.

A lot of new info has been found in the last 10 or so years.

Heh KK, your needed up top on the tropical filter question.
FWIW,
Good Hunting!