F-Type
Well-Known Member
- Messages
- 278
- Location
- Gothenburg - Center of the Universe
So, I've got one of these lemon-octanes. It's been mocking me since the beginning and I have tried everything in the school-book, well, at least the Savage Octane school book, over and over again. So in the end I came to the conclusion, it isn't any of those things that's the problem. Started reading in detail how an engine like this works, and what problems one can expect, or rather hardly expect. And eventually I found an article by some kind and knowledgeable person who had written about compression, not combustion chamber compression, but crankcase compression. So, a simple test and I could realise I had quite a blow-back from the crankcase, back through the carb and out to the air filter. So, the fuel-air mixture that is sucked in during the compression stroke, just gets blown out again the same way it came in, more or less, during the combustion stroke.
So, I installed a reed valve between the carb and the crank case. And guess what, after a year of frustration and a basically totally dead engine, it started. IT STARTED! and you know what! IT DIDN'T STOP! Not until I stopped it. And after i had stopped it, it started again in just a few pulls. So I stopped it again, and it started again in just a few pulls, same thing a third time. Unbelievable. I can hardly believe it myself as I write this!
It is way past midnight here right now, so further testing now isn't an option, especially as I have an early morning tomorrow with a long journey ahead for a week long trip.
So now I am frustrated about not being able to test the car more thorougly until more than a week away. :/
One thing that struck me in this, is that what HPI calls an "air restrictor", which I have never really believed in (I mean, who wants less air-fuel mixture in their engine?), isn't an "air restrictor", at least not in the way they make you believe. It is a cheap poor mans reed valve that really doesn't work very well, hardly at all.
I should also say that I tested to remove the reed valve and tried running the car again without it. It wouldn't start. Reed valve back on, and the car started in a few pulls.
Next thing will be to remake the throttle control, as the carb is now located a lot higher up, as it is mounted on the reed valve. I need to find a way to connect it to the throttle servo with the carb in the new high position. Any suggestions "on the fly"? So I have something to think about during next week
So, I installed a reed valve between the carb and the crank case. And guess what, after a year of frustration and a basically totally dead engine, it started. IT STARTED! and you know what! IT DIDN'T STOP! Not until I stopped it. And after i had stopped it, it started again in just a few pulls. So I stopped it again, and it started again in just a few pulls, same thing a third time. Unbelievable. I can hardly believe it myself as I write this!
It is way past midnight here right now, so further testing now isn't an option, especially as I have an early morning tomorrow with a long journey ahead for a week long trip.
So now I am frustrated about not being able to test the car more thorougly until more than a week away. :/
One thing that struck me in this, is that what HPI calls an "air restrictor", which I have never really believed in (I mean, who wants less air-fuel mixture in their engine?), isn't an "air restrictor", at least not in the way they make you believe. It is a cheap poor mans reed valve that really doesn't work very well, hardly at all.
I should also say that I tested to remove the reed valve and tried running the car again without it. It wouldn't start. Reed valve back on, and the car started in a few pulls.
Next thing will be to remake the throttle control, as the carb is now located a lot higher up, as it is mounted on the reed valve. I need to find a way to connect it to the throttle servo with the carb in the new high position. Any suggestions "on the fly"? So I have something to think about during next week