Having a senior moment but should the flap on in the snout of the air intake air filter housing be open for summer setting. I'm guessing yes as it should stop the air coming up the hot air intake tube through the tin ware? Ta. Sent from my SM-G780G using Tapatalk
It should probably be open all the time if you don't have a thermostat, otherwise you might forget it's closed and cook the engine.
I've been thinking about this recently btw, with the lack of thermostat availability (or is was the case last time I looked), I have been wondering about a new electronic system, using either a servo motor or a linear actuator, controlled by a PIC or AVR with a temp sensor. If it could fail-open, I'm not sure it would be any worse than a failed regular thermostat. Over complicating a simple mechanism? Yes, sure. I didn't want to hijack the thread. That's why I haven't mentioned @mikedjames at all otherwise we will have a design by lunch-time and your thread will be toast
Even in normal British Summer time the flap should be in hot air position at idle for some of the time - the temperature target of all the thermostatic stuff is to have idle air going into the carburettor at 35 degrees C, and Wide Open Throttle air going in at ambient temperature. The final VW thermostat system is actually cleverer than just a thermostat, as it is using the manifold vacuum as an input signal as well as a source of power. There are two earlier versions - one uses a wax capsule actuator but that doesnt allow for cooler air for wide open throttle. And earlier using the actual engine thermostat wire extended to the air cleaner I suppose the way to go forward would be to have a simple solenoid vacuum valve (e.g. eBay EGR vacuum valve ) that is controlled by the temperature at the top of the air cleaner. And feed it from the manifold vacuum so it switches over to cold air at WOT automatically. You dont need accurate control - a simple bang-bang controller will work just like stock, the time constant is fairly long.. A quick bit of research shows about a tenner for a temperature controller, and twenty pounds for an EGR valve. There you are - a bit of wiring up of boxes off eBay, job done. :
From a while ago.. not good but through a sawn off snout ... https://youtube.com/shorts/Fxp3Z7LUDAA?feature=share
Hmmm…dosnt have a thing like that one does, on the left hand side, that you can just see. Mine looks more like some sort of spring, on the right hand side…
That thing on the left is a negative pressure flap to sort of block the breathers off with the engine stopped and to ensure the crank case gases are sucked back into the engine when it's running. All it's doing is blocking off the inlet a bit. The effect is a total pressure drop of about 50mB across the air cleaner assembly.. If you have a spring thing that's likely the older wax thermostat.. greenhouse window opener.. that ignores the manifold pressure but keeps the inlet air temperature high enough for a center mount carb. The vacuum actuator is the bit in the middle going up and down. Mine is linked with a home made spring as the first time I fired it up with a progressive carburettor, the peak manifold vacuum ( drops to about 300mB air pressure in the manifold if you rev it then shut the throttle) ripped it apart...
What temp is it all meant to leap into life at, or is it instant? I will keep an eye on I, next time I start it up…
At the moment its half warm with ambient temperature at about 20C on the way to fully cold air feeding at 35C... at 0C it's probably all the way over to 100% hot air feeding . I think @redgaz found replacing this type of air cleaner with the later vacuum operated flap system improved cold running a bit more than having this wax stat type.. But even this wax stat type is miles better than nothing.
