First Post, Interesting CCV Routing, C5 4.2

Howdy.

Heard about this board from a new 'Ziner, thought I’d check it out.

While thinking about deleting my SAI valves again, I had an idea. Since the N/A V engines tend to have problems with carbon buildup and gummed up rings, why not delete the CCV system? Better yet, rather than delete CCV and end up with an oily mess somewhere, why not plumb the gases into the exhaust system instead?

And what better way to vent the crankcase into the exhaust system than through the ports formerly reserved for the SAI? My 1000RR was equipped with a system called PAIR, a check valve which used negative pressure pulses in the exhaust system to suck fresh air from the airbox, through a port in the head, and into the exhaust. Assuming such negative pulses exist in the 4.2 exhaust system, the same type of system could be used to suck crankcase gases and residual oil vapor from the crankcase, through the SAI port, and into the exhaust. Sure, oily catalytic converters and o2 sensors don’t last quite as long as clean ones, but outside of that small problem, I wonder if a net benefit could be realized. Imagine cleaner combustion chambers, higher resistance to knock, eliminating the problem of sticking rings, and possibly improving the performance of the CCV system. Sounds like a win-win!

What do y’all think?

I don’t believe the C5 4.2 engine suffers from carbon build up as it’s a multi port injection engine versus the newer “FSI” engines which are direct injection.

Sludge was more of a problem with the 1.8t’s (B6 A4’s, mk4 Jettas etc) but I wasn’t aware of any build up problems with the 4.2 C5 engine.

Now I’ve said that, weren’t there some bastard versions of the C5 4.2, with early ones being timing belt MPI, then chain driven MPI then chain driven FSI at the end of the run? Beem?

He’s referring to SAI though, a little different banger.

Ooops should’be read the post properly. But is SAI buildup a huge problem for the older 4.2’s?

Welcome new member ;D

Thag could work… I would take the two valve cover ccv hoses off and run them into a one wsy catch can and measure the amount you catch over say 90 days. If you do that you get a better idea on how bad the ccv system is effected

I probably used the wrong wording. When I had my intake manifold off, the ports were nasty with CCV buildup and the backs of the valves were all oily. As you know, oil in the combustion chamber reduces an engine’s resistance to knock, but the CCV system is nice because it handles crankcase pressure and prevents an oily mess in your engine bay.

So, in the interest of keeping my ports and combustion chambers clean, I’d like to route the CCV into the exhaust system.

Great idea…my question would he how long amd how much oil actually comes out…this should work as you suggested… I would just wonder how much improvement is there… it might take 5000 miles before you even get a little oil collecion…or you might get considersble oil aftr 5 miles… I would say get a cstch can amd see how much oil actually collects after 3000 miles…

could a pad pcv valve cause oil consumption or oil burning problems?

yes this is one of the main issues with a bad PCV

thats chrisk, im gonna pop mine off and see what it looks like inside. and replace it

They get stuck and that causes serious issues. Also check the valve cover gaskets if yo uhave a bad PCV if the PCV is bad it can take out the gaskets and cause issues there

well i had car on lift and there not a speck of any fluids leaking. the car runs smooth, but i seem to have to add oil every month. 1 quart. i get freash oil changes and then 3-4 weeks later im adding 1/2 to 1 quart of oil

Have you done a leakdown or compression test?

yes…all is good on compression test and leak down test.

Its rare to have the belt driven motors eat oil. Check the PCV and when you pull the intake for the spacers look to see if the valves are real clean and if there is any oil in the intake. That can be a sign of oil flush

yeah i did the spacers already just have not had time to put the DIY pics together and post it…been busy with work. intake ports where pretty damn clean. so intake runners where pretty much spotless of black gunky oil build up. there was however freshy fresh oil in there.

here is a pics i have now on my phone…will post full DIY ASAP

http://i.imgur.com/40Gbll4.jpg

http://i.imgur.com/zcrVn6Z.jpg

http://i.imgur.com/enttCrt.jpg

http://i.imgur.com/liGBCYD.jpg

yes this is one of the main issues with a bad PCV

thats chrisk, im gonna pop mine off and see what it looks like inside. and replace it

They get stuck and that causes serious issues. Also check the valve cover gaskets if yo uhave a bad PCV if the PCV is bad it can take out the gaskets and cause issues there

well i had car on lift and there not a speck of any fluids leaking. the car runs smooth, but i seem to have to add oil every month. 1 quart. i get freash oil changes and then 3-4 weeks later im adding 1/2 to 1 quart of oil