Here's an odd request - I'd like a photo or diagram showing typical intake/exhaust valve positions for an inline 6. I am at the "valve lifters" stage with my Aviatik's Austro Daimler and I DON'T want them to be at the same position!

Martin

One "solution" would be this: Since almost no one knows this answer, as long as you DIDN'T have them in the same position, I doubt that ANYONE would ever call you on it. That said, I'm curious as well!

So the key question is really what's the cylinder sequence?

Here's a start:

http://www.zyra.me.uk/firingo.htm

For modern Mercedes-Benz inline 6 engines the firing order is 153624

The following photo also suggests an answer:

Thanks Don - that got me off on a search. Turns out that the inlet and exhaust valves only open approx 10mm so, mine will only vary by 1/8".

Martin

Hi Martin,

I think these photos can help you out a bit,

I took the photos a few months ago at a show where I saw this magnificent 1/5th scale full working engine [8D]

Teus

First of all, what an amazing work of engineering! Second, I think that those photos demonstrate is that it doesn't really matter how we modelers position the rockers since the difference is all but invisible.

Beautiful! Is that a 160hp Mercedes?

Yes Don, even with 1/3 scale planes, the valve only travel about 1/8". Go to 1/6 scale and it's only 1/16"!

Martin

What is true is that our eyes are very sensitive to symmetry. That is we probably CAN see when all the rocker heads are in exactly the same position. So all that's really necessary is to break the symmetry and it wouldn't really matter how we break it. Here's a case were being a bit "sloppy" might actually be a good thing.

Finally, an upside!

Martin

Hey Martin

... but just in case you have nothing to do and want to offset the rocker arms, just to have it look out of symmetry, or just be be scale, or just for the heck of it...

According to a report in the Flight Journal: THE 230 H.P. BEN2 AERO ENGINE., Notes p204-212,
Magneto type, 2 Bosch Z.H.6; firing sequence of engine, from the prop: 1-5-3-6-2-4 ; numbering of cylinders from the prop back: 1-2-3-4-5-6

A couple of diagrams to help, looks like there may be alternative set-ups (see 2nd diagram)
Hope this helps,

Brian

Glad you found a definitive answer! The way I see things, we SHOULD know exactly how the aircraft we model worked...and then it's up to us to pick and choose which features we feel like modeling.