PCV in breather tower to replace breather hose?

[JoeVanagon]

Has anyone ever tried putting a positive crankcase valve (PCV) and a universal PCV filter like the link below onto the breather tower, then plugging the hose barbs on the tower and the air intake? I don't like the idea of oil being able to circulate back into the air intake, plus the breather hose is a known problem.

http://www.zenfire.ws/WarBaby/crankvent.jpg

Thanks!
Joe

[Wildthings]

[JoeVanagon]

My understanding is that PCV systems are there to relieve pressure from the crankcase. This has nothing to do with engine longevity. The problem is when spent combustion products make it past the piston rings and are then vented out the crank case. That's not great from an emissions stand point if they are vented into the atmosphere, so they decided to feed that gas back into the intake, where it might get combusted again, or at the very least it will run through the cat on the way out. The problem is that an improperly designed system can allow oil to get sucked into the intake, and cause worse problems, like belching smoke out of the exhaust, fowled plugs, fowled cat, and general badness. To my engineering mind, the root of the problem is the breather tube that can allow this. A modern PCV will not allow oil to escape as long as its working properly. So if I can somehow install a PCV instead of the breather tower, I could potentially have a more reliable system. Whether or not I vent that back into the air intake or the atmosphere depends on the likelyhood of oil escaping past the PCV. I suppose a modern PCV should work fine and allow me to vent back into the intake without any worries, but if not then I would just rather vent to atmosphere (not the best for the planet, but neither is the entire Digifant system...). I might give this a try and post my results.

Joe

[Wildthings]

PVC systems were required on cars back in the mid sixties. They cut out around 20% of automotive pollution right off the bat, as well as getting rid of the oil slick down the middle of each lane which was a major contributor to accidents. For the engine however the PCV helped remove water and other nasties from the oil which greatly improved lubrication and engine life. On earlier engines it was not unusual at all to have the rocker, push rods, and various galleys and borings clogged with sludge to the point there was no oil flow what ever. The lead in gasoline was also a major contributor to this sludge. It was not unusual to see engines with only 30K miles that were no longer getting proper oiling. I well remember pulling valve covers and finding the rocker boxes totally full of sludge to the point you couldn't see anything inside the covers at all as the rocker being hidden under the sludge, and a few years ago I pulled the pan off of a big industrial engine that dated to the early sixty and had poor crankcase ventilation. The eight gallon capacity pan was so full of sludge it would only take about a gallon of oil to fill it when it had been drained.

Blow by is nothing but partially burnt intake gases that will be mixed with almost no oil in a normal running engine. Almost all engines made over the last several decades have vented their crankcase gases into the intake air system without problems. You are trying to fix a problem that doesn't exist. There was a guy who went by the Samba handle Weatherbill that thought as you do a few years back. He was determined he needed to do something to keep the nastieds in his crankcase from venting into his intake and harming his engine. Against good advise he made his gadget and installed it. A couple of months later he was wondering why he was blowing all the oil out of his engine. He hadn't fixed a problem, he had created one where one didn't exist.

A PVC system should give cleaner oil than the sealed crankcase ventilation system VW installed originally, but most of us aren't going to be able to figure out how to install something better than the original without causing problems that may well lead to engine failure.

[randywebb]