Engine block breather upgrade?

[terrybullwon]

yes of course i would weld fittings on, whats the diagnosis on where the oil is coming from Andy?

[Rusty]

I'll do some tests on the head breather with my k24 car.. I can see that the extra acceleration on a high power car will cause more of an issue for sure. I can't test this though

As ever, a combination of factors add up to the whole problem. Understanding the areas separately will give a clearer view of the whole thing.

IMO on my ABY:-

Any oil that does go down the union pipe from the head has to flow to the sump through the 30mm pipe that comes from the sump to the T joint. Under load this 30mm pipe will be venting the crank case pressure with any gaseous or suspended oil heading in the outward (opposite) direction. For high power cars this problem will increase due to higher acceleration (more oil surge in the head & higher turbo pressure), so any oil draining down will be going against the flow at high % throttle.

The situation is worsened still on track as there are generally more right hand corners as most are a clockwise circuit. With the crank breather on the LHS there will be some surge that is forced out the breather when the engine is under load and thus the maximum crank case venting condition. This will augment the problem as the oil breather is now under assault from the head and the sump with gas/vapour/oil trying travelling in the opposite direction to each other.

With the gas forcing the oil away from the sump and the oil flowing from the head, it is left with one place to go - the same direction as the gas venting to the inlet i.e. upward from the union pipe to the tank/inlet.

Thus, this overwhelms the oil system from multiple directions and leads to the worst case scenario for my car.

With higher acceleration, turbo pressure and RPM all the things above still apply to a stock ABY breather but will be worse still, thus occurring to a greater extent without the high cornering forces.

Having not studied the 3B breather/engine I must assume that the fact that Audi redesigned the breather for the ABY indicates that it could be improved on. Larger head breather, inlet routing and the union pipe are 3 things I can think of...

Phew! That's a lot to write on a slow touchscreen phone

[s2driveruk]

i lost about 1/4 of the dipstick level and it was brimmed before the 1st session and i topped up for the 3rd so i guess if the dip is 1ltr then 250ml guzzled in 20mins of tracking it . have to say it wasnt noticeable in 60kms of Ring driving, however the speed and frequency of the rights on Combe probably exacerbated it.

[andy10v]

yes of course i would weld fittings on, whats the diagnosis on where the oil is coming from Andy?

Ok, will talk to you later when I work out sizes/part prices.

From my observations of street driving the majority of the oil was coming out the back of the valve cover, I assume due to the ***** design of the 3b valve cover oil goes to the back of the head and straight out the breather, accelerate hard in a straight line a couple of times, pull over and find fresh oil in the head breather pipe, clean up and drive sensibly, no problem.

Not to many issues with the crank breather until pushing on a bit, however my dipstick tube is also acting as a breather at the moment due to naffed o ring so perhaps not painting a true picture

If I get a chance this weekend I will hook the breathers up to separate catch tanks and measure the output under different circumstances.

[A80Avant]

nice info in here, but i was wondering, what would be the solution for cars that just occasionally go on the track and want the breather system to be just a bit more efficient than stock. Sure, welding nips on the cam cover and redirecting etc is the permanent solution, but is there an in between one?

In my solution, which i have not tested in track but only hard accelerations, i have all stock valves in place, and route both PCV lines to the tank which has 2 inlets.The smallest of the 2 i take it to the tank via a T piece, so im partially getting oil vapours there rather than all of them. The tank's outlet goes to the cam cover and that in turn back to the turbo to allow for some constant vaccum.

What i have found so far is that the tank which acts as a separator, holds the vast amount of oil and allows mostly vapours to go back towards the turbo's vacuum, therefore the inlet track contamination is less than stock. On the other hand, i can empty the 0.5l tank after a while and either throw away the contents or reuse them if they seem just oil residue. This setup does tend to fill the tank faster than before and it seems to be working fine at the moment. Obviously you could just route the tank's exit to atmosphere and keep the inlet tract and IC completelly free of any oil vapours.

[URQguy]

Another solution, a couple of big breathers from the head, crankcase breather is vented to the head (in this case via the distributor port)

http://www.motorgeek.com/viewtopic.php?f=10&t=32530&hilit=breather

Wonder if that would work ghetto style; just drilling a few big holes in the valve cover and some kind of screw though fittings on fittings and venting crankcase>head>catch tank>atmosphere or intake. How much oil do cams throw off?

Mr terrybullwon, would you weld on fittings to a cam cover for a charge?

I hope I can throw some light to my testings.. You are seeing V-1 in that picture, and you description is accurate. Since, I have deleted the tie in from the block breather to the distributer port. You see, I am using a WR block without the breather provisions so I was just using -10 bungs welded high on the oil pan. I now rely solely on the drainback in the head to relieve crank case pressure. I have run guages on both the bottom and top end to measure and log pressure under 30psi, hta35r situations. I have those two ports routed to a swirl type catch can, and vented to atmosphere. Honestly, I think I will delete the catchcan on the next revision, as no liquid leaves the modified cam cover.



To answer your question, tons of oil flicks off the cam lobes. I wish I would have taken more pictures of the process, but I basically drilled a couple dozen 1/4" holes in the valve cover where the oil does not flip up. I then layed a screen down, and then a bunch of stainless steel wool, then put the lid on. I started off with a 7a valve cover. If one does wanna duplicate the idea, those two ports ar ehwere they for the reason that they still serve as the access ports for the two allan head bolts that secure the gasket around the spark plug holes. to get the cover off, you simply have to take off the hoses and take them out.

HTH guys.

Hank

[terrybullwon]

OT Hank where did your Camber and castor plates come from?

[S2central.net]

I'm seeing LOTS of great info and detail here, but its getting already quite confusing. Can I ask someone to distill this down into something easier to digest without understanding all of the pros and cons and small details. I'd like to see a somewhat generic list of recommendations or some kind of table for some nominal power levels on our mighty engines and whether the application is pure road, some trackdays or pure race/sprint. Obviously things get more specialised at the high power levels in race mode but I hope there is a fairly simple set of options for the majority of folk who want a better breather for daily use - that is up to the job for the occasional track day.

There is definitely a market here for someone that can solve this problem with an affordable kit that works and is simple to install by mere mortals.

[JP]

My setup, combining rocker cam baffling oil separator and catch tank straight back into the turbo intake.

Pipework is as follows

-Crankcase to intake manifold through pcv valve disconnected but left connected to evap canister.
-16mm back of rocker cover into the original junction box/pipework on crankcase.
-16mm from top of rocker cover (baffled, breather holes inbetween lobes) into an oil separator which has a 16mm drain back to below oil level in the sump
-19mm from crankcase junction box into oil separator
-19mm from oil separator into the daddy of oil catch tanks (thankyou rusty)
-19mm back into intake before turbo



I can confirm that I haven't emptied anything out the catch tank since July, the level is still below the sight glass and I've only had to top my engine oil up 1ltr over the last 3-4k miles. To say that the car has a hard life is an understatement and anyone that has been in the car with me will know what I mean.
When I used a very basic catch tank on it's own it would fill up relatively quickly as the vacuum of the turbo would siphon the oil out on hard cornering as the oil surge would block the pipes. I could go through 0.5ltr of oil in less than 5 minutes.

So I decided to go for a more elaborate catch tank to make sure that at least the oil didn't make it back into the intake which worked very successfully.
Unfortunately the catch tank would still fill up quickly it just took longer due to the larger capacity.

So I knocked together an oil separator which combined with the catch tank (which is now a little overkill) I get no oil residue in my boost pipes and a very minor mist on the intake of the turbo.

Now the original Audi breather of the back of the rocker cover returns to crankcase before entering the rest of the breather system because it again can suffer from oil surge under hard acceleration, but more importantly it also doubles up as a pressure balance bar between the crankcase and head of the engine.

The plastic breather extension posted earlier in this thread is quite an effective way of offering extra rocker cover breathing without permanent mods and incorporates a baffle. You can buy them of VW and are found on MK4 2 ltr 8V Gti's, 1.6ltr 8V SE's etc... There is probably other models to but those are the ones I've seen them on. They screw into the filler cap location and subsequently your filler cap screws ontop of them. All you got to do is check for clearance.

If you are wanting to successfully scavenge crankcase pressure of the cylinderhead it is important you do 2 things
1) have a pressure balance bar to the crankcase as this is where most of the pressure is to be found from ring blow by as opposed to stemseal blowby at high rpm/boost
2) ensure the breather coming of the top of the rocker cover is baffled as camlobes at 7000rpm fling a heck of a lot of oil around!

As a side note, because I disconnected the crankcase to intake manifold breather pipe it was essential for me to return it back into the turbo to aid crankcase scavenging at idle. When I tried breathing to atmosphere the end result was that the car started to smoke heavily at prolonged periods of idle due to increase crankcase pressure causing the turbo exhaust seals to not seal properly. A common problem found on sealed dry sump systems which are not running enough pump stages.

[GazzaG60]

that breather part posted earlier is a beetle rocker breather. its a common item on 16vt. i got one here. doubt it fits the I5 though.

its sandwiched between cap and cover. the 16v though doesn't have the breathers of the I5 T.

personally i think james is right. the real way is like audi did. if your wot driving then id block and can it and weld and fit like that to the front side.

in the past i have spoken to guys on 16vt who fill a can with a quart on the 1/4 mile. gotta get rid of that pressure for nailing it.

[JP]

^^^ beetle engine is a 2ltr 8v gti

Can't see why it wouldn't fit an I5 though other than bonnet clearance?

As for most of the 16v turbo's filling catch tanks there is an issue with the location of the front block breather relative to the oil level when the dipstick reads full. I always advise 16v track cars to run their oil level half way between min and max to reduce oil consumption through the breather system.

The other problem is most of them are cheap knock togethers using already worn KR blocks and fitting S2 pistons in them or stacking gaskets on the 9A or ABF without rebuilding an already worn bottom end. For the one that I did see done properly I've never seen breathing issues.

[GazzaG60]

agree on the s2 pistons not being best. i used wiseco 83mm on a bores 9a.

most i have seen run big boost in the states. using aba blocks and proper pistons. i think the lack of head breathers on the 16v is an issue.

bonnet clearance i think may be an issue.
good post on breathers there rwd

[URQguy]

I agree with most of the suggestions above, but extensive testing does show one error in thinking.

The port on the block is for convenience and a more elogant solution for pulling ventalation on the i5. The same sort of breather could be done on the head with the same effect. The top and bottom end have sufficient balance just in the oil galleries in the head that flow back to the head. Under Accerleration, the front ports are open, under heavy breaking, the rears are open. Hard left hand turns? Slosh makes the left hand side galleries open, and vice versa.

Why do I say this? Just to bring home the fact that if you can get a good baffled outlet from the longblock, you can get very nice seperation. The stock location on the block serves as a blowhole like you would find in the ocean. As you mash the gas on high hp cars, the slosh affect rams all your oil into that galley and shoots it up that breather. If you are pulling soley from that location, you will have to do extensive seperating acts in the ways of catchcan in order to seperate everything. The better solution is baffle the head in a location and pull it off the head there.

You see a lot of early group b rally cars with valve cover ventilation for the same reason. They are the old kx/WR castings running 80mm bores WITHOUT the provisions for the side port on the crank. They understood that balancing the longblock was not nessisary other then the nessisary drainbacks.

In drysump apps, pulling just off the bottom end via the oil pan works well for the same reason. The top end balances out just fine with the bottom end stages pulling out all the pressure.

I Hope that sheds some light into what I did and tested. As I said, with big enough vents off the valve cover, you can get close to 0psi under boost.

[URQguy]

OT Hank where did your Camber and castor plates come from?

Ground control supplied the plates. They are very reasonable and have nice spherical components. I highly recommend them. An American named Haydn makes really nice waterjet parts to make it much easier to weld them in. He sells a pre-boxed top that just needs to be trimmed and welded in. You can contact him on Motorgeek using the handle Timmmy. He is good friends with Marc Swanson as well, and I am sure he could supply them as well. HTH

[JP]

The blowhole effect is a good way to describe it, one of the reasons the oil separator is required to filter out the oil and return to sump on my simplistic setup.

As for the breathing side of things drain back from the head happens in 3 locations along the exhaust side, these due to the slope of the engine and design of the head are rarely in a situation that they are not submerged irrespective of the motion/direction of the vehicle. Whereas the breathing balance is done through the 3 on the intake which amount to the equivalent of around a 16-19mm tube once the cross sectional area is added together. I can only assume that the VAG group came to the same conclusion for road going vehicles and decided to add the extra pipe on the later model engines in order to aid longevity in use.

You are also correct in saying that if you provide enough ventilation through the rocker you theoretically require nothing other than that, because if your engine is breathing so heavily it cannot vent through say a 19mm tube then there is other issues to be concerned about. In the same token it is not an easy solution for the average person however for an out and out race motor it is easily achievable.

Just out of interest I assume you are venting to atmosphere, as on a well balanced sealed system I would hope to see a vacuum?