|08-31-2010 07:43 PM|
Run a compression test. If it comes out good, run a leak down test. If it comes out good, a PCV system will help you.
Here's why. All piston engines, no matter how well they are built, will have some blow-by past the rings. The blow-by collects in the crank case. At highway speeds, assuming it is not plugged up and you haven't altered the car in a way which will alter the air flow past the end of the road draft tube, the air passing over the end of the road draft tube will draw the blow-by out of the crankcase. Around town or idling, not so much. The blow-by will mix with moisture in the air and create acids in your oil. Results - sludge (or more frequent oil changes) and premature engine wear. A PCV system increases engine life because the "positive" in positive crankcase ventilation is just that; positive (and all the time).
If the engine fails a compression and/or leak down test, it probably doesn't matter.
|08-31-2010 03:48 PM|
I acquired an old LeMans with a worn out 326 once. I liked the car with the 4 speed but it smoked something awful. Back in 74 Mobile oil had started selling it's Mobile 1 syn. oil and claimed a higher flash point being synthetic. So, I decided to experiment with it and at 5.00 a qt. (really high dollar back then)
I changed the oil and WALLA! no smoke. Only problem was it still used the same amount of oil at 5 bucks a qt. and it smelled like crap.
The cop's can cite you in California for excessive smoke but not for wasting money and grossing out everyone that follows you down the road.
|08-31-2010 12:35 PM|
|08-30-2010 10:20 PM|
You wanted to know what might need to be fixed to stop the blow-by.
Rings could be worn. Cylinders could have a large amount of taper causing compression to be lost past the rings.
Bad valve guides on the exhaust valves allowing hot gasses to be pushed into the engine. All not good.
|08-30-2010 09:36 PM|
|SSedan64||If it's blowing oil you may need one of these>> http://www.condensator.com/ or http://www.pbase.com/rsrock/oil_catch_can|
|08-30-2010 09:26 PM|
To controll crankcase pressure and keep the engine from throwing oil and fumes out of the breather caps. On a high mileage worn out engine, it might keep the stink of blowby out of your nose!
|08-30-2010 08:15 PM|
|08-30-2010 07:07 PM|
|F-BIRD'88||Do your self a favour, Most of the pretty aftermarket valve covers have crappy PCV breather baffling. Make sure the baffling is in order to prevent/minimize oil migration into the intake manifold. There are lots of advantages to running a PCV.|
|08-30-2010 06:50 PM|
|68NovaSS||Build up enough crankcase pressure, maybe flow oil past the front and rear mains? Prevent blowby past the rings? There are advantages.|
|08-30-2010 06:50 PM|
Hey Man, On a near about stocker IMHO, No. When you start getting up in the HP, maybe the crankcase suction might help with ring seal and condensat
ion? Others may have opinions on this. olnolan
|08-30-2010 06:46 PM|
Not really. Some people say that the small amount of oil being mixed in with the air/fuel mixture lubes the upper cylinder walls. But if you have enough blow-by that oil is dripping onto the roadway then you may need more work than just a pcv up-grade.
|08-30-2010 06:33 PM|
on older engine--should convert to PCV valve setup?
Besides spraying oil out of the breather pipe is there any advantage to converting to a PCV valve set-up?