[30ONA]

please correct as required.
How a PCV system works.
1. Engine starts and idle.
2. At idle there is a vacuum behind the throttle body. This vacuum and any pressure built up in the crank case circulates air from the crank case into the inlet manifold via the pcv valve which is open.
3. As the throttle opens and the vacuum in the inlet manifold drops and the pcv valve closes........crank case pressure increases from......now I don't know what happens. Or I'm wrong.

[losfer]

No Max you got it all wrong....

You shouldnt do this as the pcv contains harmful hydrocarbons etc in it but , if you were to take out the pcv valve and suck on the end that goes to the intake manifold it would close. the higher the vacuum (ie at idle) the least the pcv is open the less it flows , the less the intake vacuum (ie at full throttle) the more the pcv valves opens and allows crankcase gases to escape through the pcv valve.

when you remove the hose and pcv from the rocker cover and put your finger on it with engine running and you can feel the the vacuum its because the valve has become open , like at full throttle , when you remove your finger it snaps shut ie almost closed like at idle.

should be able to find some youtube vids on it?

[losfer]

I tried to explain this on the phone to you, and usually i hate giving out my secrets, but the easiest way to determine if the pcv is working , is to find another opening to the crankcase or rocker cover , ie dipstick tube , oil cap or the breather tube from intake to rocker cover. Get a small piece of paper to cover the opening , you will need thicker cardboard if its the oil cap as the paper will not create a good seal as it is sucked into the larger orifice. you will feel a good vacuum on the paper/ cardboard.

[losfer]

Oil consumption - especially when there is no obvious clouds of smoke on startup , acceleration or deceleration and no major oil leaks can be a fairly hard thing to pinpoint to one exact location. The condition of spark plugs and inspection of piston crowns with a borescope can often tell a story.

as someone suggested a wet and dry compression test will show you the overall condition of the sealing of the combustion chamber But it doesnt really give you a great picture. A leakdown tester can also be used to give you an idea of piston ring and valve seat sealing because you can hear where the leak is coming from and compare the diffference between a known leak and an unknown leak.

Regarding the dry compression test it will show you, providing the valves are seating perfectly , how well the compression rings are sealing , if you have very low compression on a cylinder a wet test will show you if its valves or rings. a very high reading after a wet test would suggest a ring problem a low result would be valves.

Then we have a few different other scenarios.

Valve stem seals old/hard but valve guides good . this will cause no smoke on startup but on every intake stroke and on other strokes where there is less vacuum it will draw a small amount of oil down the valve stem.

Stuck oil control rings - seen this so many times its not funny. oil control rings are designed to distribute a small amount of oil into the crosshatching of the bores to help lubricate and seal the first and second compression rings. When oil control rings become seized in the ring land oil supply is not distributed in a controlled way and will cause a consistent use of oil.
oil rings generally are the first thing to get stuck when they become gummed up from lack of servicing/oil changes. you can generally get an idea if you take off the oil cap and take a look at the caps on the camshaft(where possible). If anything darker than a light tan or a gummy buildup its had little service history.

Glazed bores will also do a similar thing.

Piston rings are fairly complex in their design and even one ring upside down will cause a dramatic oil use /smoke issue (this is an example its not the cause of his oil usage) the top compression ring has a taper on the inside upper edge , a small amount of combustion gases actually force this out to the cylinder to make a good seal. The second compression ring has a bevel edge on the lower side that acts as a scraper to scrape oil from the oil ring down. The oil control ring has two rails that are seated on an expander to push it out to the cylinder walls.
The two oil control rails , the second compression ring and the top rings all have gaps in them which are staggered so that oil cannot pass past them.
When installing rings i have a saying "tape her up and scrape her down" in relation to the taper and scraper on the top compression rings.

to give you an idea of oil usage in perspective. if you were to do 8000 km at 100km/h it would take you 80 hours. at 3000rpm you are doing 180000 rpm per hour. in 80 hours , thats 14400000 revolutions. if you used 5000ml (or 5l) of oil in that time it is .000347222ml per revolution , thats 1.04ml per minute !

[fordem]

30ONA wrote:

please correct as required.
How a PCV system works.
1. Engine starts and idle.
2. At idle there is a vacuum behind the throttle body. This vacuum and any pressure built up in the crank case circulates air from the crank case into the inlet manifold via the pcv valve which is open.
At this time the PCV valve is open, but will allow minimum flow.
3. As the throttle opens and the vacuum in the inlet manifold drops and the pcv valve closes........crank case pressure increases from......now I don't know what happens. Or I'm wrong.
As the vacuum in the intake manifold drops, the PCV valve opens more, allowing increased flow.

This has been explained at least twice before...

[30ONA]

Thanks for all comments re PCV's. I a better article on the net that I hadn't found before that confirmed everything you have all said and put it together with some pictures also. Two things that didn't click to me till now, were 1. realising there is an air feed into the crankcase (rocker cover) just in front of the throttle, the second thing is that the valve is not just open or closed (can close under backfire), it has two functioning parts with graduated flow. I know this was explained previously so thanks and sorry for the thickness. Kinesthetic learning is my excuse.

I am also seeking professional Suzuki assistance about the oil and idle.

For anyone else interested this is the article I was reading. http://www.naijacarlovers.com/2016/03/p ... n-pcv.html