2-Stroke engine design resources

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Apr 3, 2017
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Hi All,

when you're Googling and nothing comes up, you know your hobby is niche/cool!! 😂

I have been looking for online resources regarding the design of model 2-stroke engines (particularly CI 'diesel' engines) without much luck.

@edholly put me on to some great site that allows you to convert from piston height to angular rotation (TorqSoft - Piston Position - Calculation Tool) but was wondering if there were other things out there that people know of/could share.

I'd like to educate myself the effect of port timing, stroke length, SPI etc on engine handling characteristics such as ease of starting/power/efficiency with a view to being able to design my own engine one day. I am guessing there might be some papers kicking about that address these topics. To date, I have just copied designs from existing engines (which has worked out great) but I would be at a loss to make a decision at design time to add a few degrees here and there to change the characteristics e.g if I were looking to make a v high performance, hard to start, short lifespan sports engine.... what would I do?

I would also love to be able to create one of the diagrams below. This is from the MotorBoys plan book and looks to be created by some sort of software rather than hand-cobbled. I wrote a simple program to do this a couple of years back but I lost it when my laptop died... lesson learned there.

Any resources people could share would be much appreciated.


I wrote a series on high performance two strokes as well as a series on building the modern model nitro race engines. In addition, there's a wealth of information on model engine design and construction here:
https://web.archive.org/web/20181118222707/http://www.modelenginenews.org/I have a lot more detailed information including dyno tests and engine simulation information, but it's all related to high performance small two strokes.

Really comprehensive information on all engines can be found in this two volume set:
My personal favorite is:
Lohring Miller


  • High Power Two Stroke Design.pdf
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  • High Power Two Stroke Design Part 2.pdf
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  • High Power Two Stroke Design Part 3.pdf
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  • High Power Two Stroke Design.pdf
    1.4 MB · Views: 16

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