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Keeping oil from coking up the intake valves on our DI engines

17K views 84 replies 27 participants last post by  cobrajet429 
#1 · (Edited)
Ford is doing some things with their DI engines to minimize this, but oil still gets in there through the intake because of the PCV/breather system and there is no fuel hitting the intake valves to keep them clean.

Sooooo, a budget-minded two phase plan. Phase 1 finished (edit: gonna go a different route):





Phase 2 coming:

 
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#4 ·
Oil can get into the intake from two sources. 1. The valve cover/cam cover breather system which I have just separated from the air intake and the PCV system which I am using h catch can for.

Most of it is from the PCV system, but the valve cover/cam cover breather gets some too.

The breather tube for the valve cover is mostly an emissions control system. Old engines, and racing engines, use an open breather here (many did not/do not even use a PCV system---on my Mustang I use a vacuum pump). The EPA does not want oil fumes into the air. Thus the tube I eliminated.
 
#16 ·
My buddy put a oil separator from the valve cover to intake air line and had not one drop of oil. It is possible oil vapors are far less. The main area is from the crankcase behind the manifold. James Baron Racing has detailed pictures of this.
 
#10 ·
Wouldn't the fuel being injected right into the cylinder help keep the valves clean? If you are using good fuel that it.
 
#24 ·
And I have a separate thread on the PCV system which has just completed except for the actual valve identification instead of a 'Ported orifice'.

Try starting here for the '12+ Focus:
http://www.focusfanatics.com/forum/showthread.php?p=4709595#post4709595

My other threads are in BITOG but they are incomplete since my attention has wavered greatly. I am not yet convinced that we have an issue, time and pictures of intake valves will show 'proof' but I don't know that we are there yet when it comes to time and miles on several engines for the 2012/13 models. We just don't have the miles and failures yet to say for sure.
 
#30 ·
Well, I've been thinking, in order for this system to function better as an open system, I am going to have to add another breather to the valve/cam cover where the oil fill cap is.

Although the hose to the intake hose supposedly pulls air INTO the valve/cam cover, there was still oil all the way through the tube. Not much in the intake hose, but of course this is an NA engine. But vapors were getting in there somehow, so it must not be completely efficient.

In the past, on non-race engines where I have kept the PCV system, I have always had a rather large breather in the valve cover with the oil fill (like I did with my Lightning, and many do with late model Mustangs), but in retrospect what I have now is really not big enough. Two would be ideal to allow fresh air into the engine crankcase and allow vapors to vent. Then a catch can on the PCV side would be ideal.

If I were just starting from scratch, then there would be no PCV and instead a catch can with breather coming from the crankcase port (since most inline 4cyls use such a port for the PCV---I could still use the stock oil separator) and two large breathers on the valve/cam cover.

Even better, I'd love to do a closed vacuum pump system like my Mustang (maybe use and electric pump instead--an '03-'04 Cobra Mustang is a good source for one).

The pump I put on my Mustang:


I am going to work on this Focus system some more.

This thread is great. Gets us thinking on this. I am going to end up with something completely different than what I started on.
 
#33 ·
I can see how the breather hose on the cam cover gets oil in it. While in normal operation the flow is from intake to cam cover for PCV supply (They use the main filter instead of a separate unit), when you are at WOT there is essentially no vacuum differential and therefore no flow since the butterflies are wide open you get no pressure differential for the PCV system. So, when at WOT there will be blowby and some small amount of oil would travel UP the breather tube. When I was playing with V8's I used to see some oil in the cam cover filters, it was not much but it was there.
 
#36 ·
I was gonna put a oil catch can on my Focus and make a how to thread. Then I found out what hose I would have to get at. Too much work to get to that little hose on the inside of the intake manifold. I am really curious how well that stock oil separator works though.
 
#40 ·
Same here on anything I build the engine for, or an older vehicle. I just need to find the best system on this engine. I will probably keep PCV valve on this car I am sure, but probably use 2 breathers on valve cover and a separator/ catch can on th PCV side.
 
#43 ·
Can someone explain this thread in plain english (noob) terms? Not understanding what this is about.

Sounds like it has to do with something about keeping oil off the valves but that's about all I understand.
 
#47 ·
I would like to see some bore scope images, preferably on some cars with higher mileage.
 
#49 ·
Maybe bring the borescope to FF? If you had that and some of the cleaner, you could definitely prove/disprove the need in person. Surely there will be at least some Mk3's with relatively high mileage[dunno]
 
#50 ·
That's a great idea and also a good sales tactic for Aron to take into consideration. Then you will have images to add to the website as well.
 
#51 ·
one of my coworkers performed a walnut service on a BMW a few weeks back. he took before and after pics of the valves. I'll see if I can find those for you guys.

And if you're wondering what a walnut service is, it's like glassbeading but the crushed walnut shells are degradable in the engine. still requires removing the Intake manifold though.
 
#53 ·
What about what I would do on my MOPAR's a sealed breather that has the hose attachment one on each cover hose goes to reed valve's at an angle in the collector of the headers so exhaust pulses would pull out vapors and burn in hot exhaust? Would also auto lube the muffler bearing....

[werd]
 
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