Tom, I think maybe it's time to dig out a few of those instructional threads from a few years ago. Y'know, the ones that began "Let's talk about...". Those were great.
+1 I read most of your Articles on the yahoo page( awful to navigate by the way) and I reckon ye should publish them in a chapter format somehow.... Didn't jump in right away coz well to many posts makes Aussiedave a PITA... But I was wondering about mixture flow as it leaves the injector manifold into the inlet chamber ( bowl?) does the bowl act as a Venturi type affair and speed up the flow as it reduces volume to the inlet port or does it act to slow the flow down and increase the static pressure? Or should it try to maintain the existing velocity? Also previous posts have mentioned that the length of the efi manifold functioned to decrease turbulence- I think some one said their mileage decreased when they put pods directly on the injector. But isn't turbulence a good thing - keeping the fuel in suspension and helping an efficient burn?
Yes , thanks Ace , that helps my understanding muchly. I find it remarkable that you are able to create a positive pressure in the cylinder with your raised port design, just using induction and the momentum of the air! My understanding is that most engines still have a slight vacume at the end of the induction stroke- that is , they don't fill completely to atpospheric pressure. It certainly is a tricky environment for air flow and I find it fascinating. Wish I could see your flow bench in action. I'm curious as to how you model the changes you make-are there simulations you can run try different shapes in the passages? I hope I'm not encroaching on your trade secrets:)
This is a general question on engines, related to kick start gear.The electric starter motor gears are connected to crankshaft through sprag clutch mechanism that transfer power when required. I guess there is no such sprag clutch mechanism for the kick start gear. How does kick start gear engage and disengage from the transmission shaft that it rotates to start an engine ? Do you have any pictures to clearly see how it is connected in RE ?
It is a simple ratchet/pawl system. It is not engaged during running, like the sprag. A sprag ts sort of like a ratchet mechanism too, but it stays engaged with the engine gears all the time, and so it is vulnerable.I am posting from my phone right now, so I can't put any photos up. The kick start ratchet and pawl parts can be seen in the exploded diagram in the parts book.Also, these kick start pawls and springs sometimes break too, but it is cheap and easy to fix it. I personally think that a "bendix" type of electric starter, like cars have, would be a better choice than a sprag starter system.
So the pawl can break on a kick back, if the kick lever is held down and not allowed to return !That would require splitting the crankcase, isn't it ?
Tom:Can you discuss on the use of two smaller size intake/exhaust valve set vs one larger size valve for intake/exhaust in an engine ? How do you decide when to use 2 valve-set and when to stick to 1 valve-set ?