enginehistory.org

szielinski · Joined: 13 Jul 2003 Posts: 94 Location: Canberra, Australia

I'm having trouble finding anything on the web that relates to asymmetrical timing/tuning for 2-strokes.
I have found plenty of stuff relating to simple piston-ported 2-strokes, but it is all based around the obvious symmetry of such a design.
I have the RRHT book on the Crecy, but it only describes what the port timings ended up being, not how they were derived or what worked best at what load/rpm.
Ideas anyone ?

jrussell · Joined: 26 May 2004 Posts: 55 Location: Portland, Oregon

Back in the the mid 70's, a book titled " Two stroke tuners handbook" was written by a gentleman named Gordon Jennings ( who wrote a column for Cycle magazine). It was an overview of the tuning theory largely explaining the fundamentals of intake and exhaust harmonics, giving the formula for pridicting wave timing and amplitude. It cited many SAE papers, published by Honda and Yamaha engineers. As I remember, it was far superior to the average writing on the subject, in terms of giving a technical understanding of the subject. I wish Kevin Cameron would write a similiar tome! Also, as a rather unusual suggestion, I would like to propose as a possibility, researching Navy training manuals published in the 50's and 60's. I have found them to be a suprisingly good source of indepth technical information regarding design philosophy. The manuals written after this were " dumbed down " tremendously.

szielinski · Joined: 13 Jul 2003 Posts: 94 Location: Canberra, Australia

Thanks for that.
Since I'm in Australia, I doubt I'd have the access to documents you would, but you've got me thinking, I do have a friend in the RAAF who might just....

kmccutcheon · Posted: Sun Feb 13, 2005 16:02 Post subject:

I posed this question to Kevin Cameron who suggested

Schweitzer, Paul H.
SCAVENGING OF TWO-STROKE CYCLE DIESEL ENGINES.
The Macmillan Co., 1949.

I found five of these available from http://www.abebooks.com/ starting at around US $22.00. Most are in the US and one is in the UK, but unfortunately none in Australia.

According to Kevin, Mr. Schweitzer uses time-area analysis to decide the shape, size and placement of ports.
_________________
Kimble D. McCutcheon

wallan · Joined: 13 Jul 2003 Posts: 252 Location: UK

One book, unfortunately out of print, that you might like to look at is C. Bossaglia’s, Two-stroke High Performance Engine Design and Tuning. (he’s the guy who was behind IAME engines, plus a number of car, motorbike and karting engines)

http://www.lortim.demon.co.uk/reviews/Bossaglia.htm

He seems to be the last hands-on developer, before the age of the computer.