hobot, I know you are familiar with the Spintron and what it is capable of, but many may not realise exactly what it is .
Try the following to get a good rundown on the equipment and it's use
www://trendperformance.com/files/Brochu ... torial.pdf
You'll notice that a hog has been tested, but mainly the Nascar V8's. Very, very expensive equipment to use for evaluating a single or twin cylinder pushrod motorcycle engine, I don't know personally of anyone who has done it, hence my original question.
I have used Spintron equipment in the past, but only when working on a V8. I also use a computer program which I have found by comparison is so good and compares extremely well with Spintron results. This is handy for me, I can carry it around on my laptop.
The computer program allows the user to evaluate all aspects of the valve train, but it does one thing not possible with the Spintron - it can simulate the exhaust valve opening against the high cylinder pressure in a firing engine. This latter shows up the exhaust valve opening in a different light, and can be much of the reason for an opening lag of some considerable number of crankshaft degrees, especially when compared to a motored simulation, where the situation would be identical to that using the Spintron.
Anyone timing up an engine might congratulate themselves in having split hairs to get events exactly to the designers spec, but in a pushrod engine valve events will be much different dynamically, and the more so as the revs rise and the loadings increase. Whether the original designer knew this and made allowances in his design is doubtful, but for certain there are some very useful gains to be had when a designer learns how to take these discrepancies into account, and makes a plan to have them working for him, rather than against. When I find out how to post a picture, I'll try to add a couple to illustrate.
