I would also like to hear Mr. Hall's thoughts on the Gordon Jennings 2-stroke articles/book.
I bought the first edition of the Two Stroke Tuners Hand Books Gordon Jennings published. It was turquoise in color and about 1973. I was in my 1st year of Engineering studies and my foundation in physics and high-level math was weak at this point. Gordon did a good job of making me think about some of the ways I had been doing things and I did not need high-level math to do any of his recommended calculations.
Jennings seemed to have a lot of experience working on two strokes but I do not think that Jennings's was educated as an engineer. It appeared that he had the aptitude to become a top-notch engineer if he had taken the time to study all of the stuff that is taught in the colleges of engineering at most major universities.
I believe that engineers are born and not created in a university. I have seen many guys without the aptitudes for engineering get engineering degrees that are terrible engineers. I have seen many guys that have an aptitude for engineering that never went to college do things that astonish their piers. Getting a formal engineering education at a university will give you about a 20 to 30 year head start over someone that is an engineer by "experience".
My mentor is a genius and is 91 years old, he never went to college (his family could not afford to help him) and can he can usually get me back on track with just about any project I need help with. He has a string of patents a mile long on all types of things. One of his patents is still used on the navigation system used on just about every commercial airliner flying. He has worked on projects for a host of aircraft companies as well as many top secret military projects that after 40 years he still cannot talk about.
As my engineering education progressed I was better able to understand what was published in the SAE papers that engineers from many of the engine manufactures and Professor Gordon Blair for the Queens University of Belfast had published. Studying the SAE papers gave me a whole new level of understanding of two strokes. While doing my engineering studies, I started a shop in my parent’s garage. I had a mill, lathe, dyno, cone rollers, porting tools, tig welder, mig welder, and a torch to weld pipes.
I started modifying engines and doing a lot of dyno testing while in college. I found that that the formulas for ports and pipe that were in Jennings's book, did not work very well on the types of two stroke engines I was working on. The guidance I received from the SAE papers was more accurate and produced much better results.
I think that Gordon Jennings's book is a very good introduction to the world of two stroke engines. Just be careful in placing very much faith in his formulas. Two-stroke technology has come a long way since the engines that Jennings used as state of the art models in his book. Be careful with some of his conclusions and theories on reading spark plugs.
I am trying to get my thought organized on how to present my experience on reading spark plugs. Looking at spark plugs is not an exact science like most of the authors of articles I have read want you to believe. A lot of tuners I have been associated with make errors reading spark plugs because they do not consider the variables that influence what they are seeing when they read a spark plug. I may need to write a book to provide the readers with enough foundation so that they can better under stand what the spark plug can reveal and why and what the spark plug cannot reveal to someone studying it.
Not knowing the level of understanding that the majority of the readers on this forum has about engines and basic physics, it would probably better for me to make a statement and brief explanation and let guys ask questions so that I can try to give an explanation that most will understand.
