But, but, but. I agree there is no option other than into the filter as you describe with aftermarket filters, but that doesn't make it better than a filtered oil breather system. I guess that's not what you meant?
Thanks Westy. Ok the plan was fuel tank breather to one carb and crankcase breather to the other, so I'll stick with that. Better buy some of those little blue elbows then
You guessed correctly. The engine doesn’t have a good breather system because there is no way for air to get into the crankcase, all you can do is draw fumes that have blown passed the pistons and pass it back into the carbs – that’s what VW did. On a decent positive ventilation system there would be a filter to allow clean air into the crankcase and a vent to pull the contaminated fumes out.
If you have cast filter covers drill and tap for the elbow, with tin covers just push the elbow into a grommet. No need for nuts inside the filter.
I wonder how much power is lost just pushing air from one end of the engine to the other? Some clever person has probably worked it out – I’m not that clever person.
I took the cast ones off with the hexbar - kept as spare - so have tin ones now. Somebody recommended using plastic nuts so if they fall off they won't do the damage that metal ones would inside the combustion chamber. Is that right?
I’d use Aerotight/aero lock nuts to hold your filters down. They’re pretty cheap, and don’t come undone.
I wouldn’t have nuts inside the filter, but if you do, plastic will probably do less damage than metal when they fall off. But why use nuts at all?
Nor me but at the same time you can imagine the benefits from making that flow as easy as possible pistons going up must be held back by a -ve pressure while pistons coming down against +ve pressure. To varying degrees people make the passages bigger and round them off for best flow like a venturi. Then add another breather at the other end. Kind of like a balance pipe, smooth it out and relieve at at much as they can. Racers of course, always after another 1/2 HP but who knows?
Some things are proven winners for all engines - a good valve job being the obvious one but it's very difficult to guess the gain from others.
I’m not after the last ½ hp but it’s good to make the engine as efficient as possible and I cleaned up and rounded off those passages and made sure that the cut-out in the cylinder skirt lined up (the biral cylinders didn’t have any from AA). I also have a counterweighted crank which fills the case and it must be absolute mayhem in there.
Crikey what an excellent example! I agree, just to be kind to the components it's worth doing this kind of thing I feel, even if there's no appreciable gain in power it's going to have an easier life all the time.
Of course it’s a Type 4, I wouldn’t waste my time with a Type 1. Daft way to fix a flywheel, funny windmill thing in a dog kennel on top of the engine – and that oil system; whatever were VW thinking. Speak to zedders if you want to see huge pistons.
