I’m not so sure that I have a fuel breather system as such as mines a 1970 early. If on further research I can find a breather system of some description, im thinking yours is a very good set up to copy. Ozziedog,,,,,,,,,,thanks for the response.
Mike,,,, are you suggesting that I fit a rubber one way valve to my rear Ozziedog,,,,,,,,How very very rude
The fuel tank will be vented, do you have the pipes within the engine bay? I recently replaced when I fitted a new tank.
Mine’s a 1970 Ozzie, I think the fuel tank only vents to the small hole inside the filler flap. Sent from my iPhone using Tapatalk
That’s what I was thinking but had my ‘Unsure’ head on as I was off to work. Ozziedog,,,,,,,,, Worserer head on now with savvi Blanc and Fosters clouding things
That angry looking spare 1776 motor that looks / glares at me as I pass by in my garage has ventilated rockers but I must go and see where they go. Ozziedog,,,,,,,,,,,,part of why I chipped in
Normally, to a breather box…Then a pipe goes back down to the oil filler, T’D off of a pipe to the filter, I think.
Actually, if you watch the rail buggy’s in action and realise the down hill angles they achieve, then there is a need to vent the covers to the Empi box, or the covers will leak, due to the unusual angles. Wouldn’t drive a van or a beetle at those angles in everyday use, mind. But we are talking high performance rail cars, in sand dunes, innit.
Don’t you want the opposite as with a vent box the the oil would be able to run out of the engine at extreme angles you maybe getting mixed up with catch tanks I thought they were used on drag cars as they run at high revs so you want the air to escape rather than being compressed adding to valve resistance
It’s just what I read about performance engines in rail cars, matty. Too much oil in the covers are a bad thing leading to more pressure, and leaks apparently.
Crankcase pressure comes from combustion gasses which get past the rings.Basically a failure of the ring/piston/cylinder seal. The bigger the displacement, the more blowby there is. A 2100cc engine will have more blowby than a 1600, if the rings are sealing the same amount. Roughly 25% more. If a specific amount leaks every firing, then you get 2x as much at 4k RPM as at 2k RPM. Obviously 6k and 8k are worse. Also, the more pressure there is in the crankcase, the WORSE rings seal. Rings seal by pressure DIFFERENTIAL from top and bottom of the ring (Pressure goes above the ring and BEHIND the ring, pressing the ring outward and sealing it tightly against the cylinder. Pressure from above seals it against ring land on piston. If the pressure below the ring is the same as above the ring, there is 0 seal, and combustion goes straight into the crankcase. It doesn't take much to be a problem. A good ring seal is 95% effective, 90% effective will win 0 races. This is why ventilating the crankcase is important. And why a vacuum pump is so effective at making power. Besides evacuating gasses which rob the engine of power (pumping losses of the gasses in the crankcase, AND windage), the vacuum makes the rings seal better. Which reduces blowby, and increases power. A stock breather setup barely works for 4k RPMs on a 1600. Up it to 2100cc, now the limit is like 3k RPM. Oh, you want to rev to 6k? Need double the breathing capacity. The box simply needs to capture the oil, and be higher than the engine to allow the oil to drain back into the engine. If the box is low now it's a catch can and not a breather box. The tower style breathers are ugly, but effective. On my car I have the generic 1/2qt box, but it's mounted to the firewall in front of the fan shroud (to the right side of the deck lid spring). Hoses route steadily downward to the engine for drain back. No puddling. _________________
My 90 year old mother gave me this information as she and Tony Hart used to race VW things against Rommel in WWII…
Vented rocker covers are used in engines that have a larger crank than stock and run at a lot higher rpm This causes excessive pressure in the crank case that in extremes can pressurise the rocker covers It’s only because the stock breather hole isn’t wide enough when the above modifications are made
Unless Soggz is talking about drag racing gas ported pistons I’m calling BS . All of my Type 4 engines have vented rockers from factory and all were capped from factory . Mr Raby states there is no need to vent the rockers even in race engines that see constant 8k rpm . Unless your running big turbo it’s just shiny tat ( according to James at stateside ) then your running dry sump anyway
