Hi guys, I'm looking for some advice regarding PCV / breathers and the oil leak that I have. First of all I'm a newbie when it comes to V8 / American cars (hailing from sunny Scotland). Car is a 65 skylark with a 300 V8. It has a non-standard cam (no idea of spec), carter carb and massive k&n filter. It was used for rwyb racing in california before it was shipped over here (no rear seat / cut off switch on rear / remains of massive sacramento raceway sticker on rear window and old drag event dash plaques in the glovebox). No idea if it was purely track or if it was used on the street. However I am now using it on the street. The problem I have is that I'm getting oil mist / spray from the breather over the valve cover on the drivers side (it has one of those mushroom filters). It has a PCV valve on the passenger side but the pipe is venting to fresh air not attached the filter / carb. What I think is the port where this should be attached on the carb is currently blocked off. The problem is I have no idea why this has been done. Was it because of the racing? Can I simply hook it back up? If I start the engine with the filter and pcv valve out within a minute you can see vapours escaping from the grommets. Oil pressure is usually about the 40psi mark (always has been since I got the car) but can go up to 50-55 when floored. Just looking for some advice - thanks in advance Paul
Start with a new pcv valve and hose. Hook up to correct place on carb . Clean the breather filter. But chances are they ran that engine hard and you have worn rings.
Like Andy says, rings are worn. You are seeing a ton of blow-by past them. Does it smoke out the exhaust? It is potentially something else if it isn't smoking.
I agree that you should hook up your PCV valve to the vacuum port on the bottom of your carb (typically 5/16 or 3/8" hose connection on the base plate). If there is no port on the carb base plate, there might be a port available on the intake manifold, or a provision for one. It is normal for all engines to have oil mist and the PCV (positive crankcase ventilation) is designed to handle the typical ring blow by, so I wouldn't jump to the conclusion of worn rings just yet. Try hooking up your PCV valve correctly to vacuum. One thing to remember is that PCV valves are engine specific and typically will not work properly if the engine has been modified. I had oil mist on my engine and changed my PCV Valve to a M/E Wagner adjustable PCV valve and it works great and solved my oil mist problem. It is pricey, so I would try just hooking up your existing PCV valve up first. Good luck and let us know how it goes!
Sounds fairly normal. They used the mushroom breather because when they installed the K&N filter they didn't add the fitting underneath (on the lower filter pan) for the breather hose that goes to that side. If you add those parts you will take care of the smoke and oil on that side, it takes a 5/8 or 3/4" hose, heater hose will work. Then they probably blocked off the PCV valve because they were getting blowby out of the breather. People do some ignorant things with pcv. Jim
Funny.. One of the turbo cars I had, had some blowby out the valve cover. It had the stock PCV setup with a chrome breather. I plumbed the valve cover vent so that it dripped on the downpipe with low pressure hydraulic hose. Problem solved. It's very little oil anyway. It was not noticeable. There are other solutions where people use a reservoir etc. Send it to a coffee can and dump it back in the crankcase.
Cleaned out the mushroom filter - what I mean is I sprayed the filter with cleaner that promptly turned the foam inside it to a thick paste of goo of oil and melted foam. Because I'm in Scotland I can't just pop down to the local auto place and pickup a new filter so managed to get all the old foam out and repacked it with new foam which is better than nothing. Cleaned the PCV as best I could and hooked up the pipe to the previously blocked port on the carb. Seems to have cured the oil on the valve cover problem but I hate to think what the inside of the carb looks like. Still got a smell of hot oil from the engine as there a couple of small leaks here and there. Since hooking it up I've done a few shows - hotrod and hills 2 hours of motorway driving at 65 to 70ish, a couple of days in the local area and then another 2 hours back home. A few local shows (within 30mile radius) and currently on my summer holidays - a week touring about in the buick fully loaded with camping gear and family taking in the British NSRA Supernats before heading home - probably best part of 700miles or so. So far no major oil spray. It is using a bit of oil which I'm assuming it's burning (worn rings) but it's running and I don't want to take it off the road to strip the engine during our show season Paul
Paul, Great news. Glad your enjoying the car with the family! Thanks for letting us know what progress you have made to date.
