1.4 TSI 118KW Oil catch can

[blower]

Hi,

As part of numerous performance upgrades to my 1.4 TSI 118KW Golf mk6 I wanted to fit a catch can. Having just fitted forged pistons and cleaned out the heavily carboned up intake and valves whilst the head was off, I wanted to try and reduce future build up.

Most catch can's on the market are useless as they don't contain an adequate or any baffle to catch the oil droplets, so I have taken a cheap ebay catch can and modified it with an internal baffle.

Also getting a catch can to fit the 1.4 TSI is tricky....

Cheap ebay can with narrow barbs and absolutely useless tubing thats too small, collapses under vacuum and turns into butter with the heat:







Internal baffle plates i made out of perforated stainless steel sheet and some stainless threaded rod to support it at the top of the can:





I also filled the gap with stainless scourer material:





Here are all the parts of the catch can, with the hole drilled and threaded for the side access and new barbs:





The baffle inserted...i filled some gaps at the top with high temp jb weld epoxy just to provide a better seal and make sure all oil vapours are forced through the baffle:





Here is how i modified the PCV pipe - cutting the pipe from the timing cover and jb welding in a barb:





With the outlet plastic part from the timing cover i cut off the end, threaded it and inserted a right angle barb:





I had trouble finding somewhere to put the can - the only real place is where it is now. I modified the battery tray, cutting off some of the corner edge so i could bolt a right angle bracket to it to hold the can:





The piping i used is designed for high pressure and also oil/fuel, 16mm ID - i have seen people that have used silicone hosing for PCV - this is bad, as unless its fluoro lined then at the PCV temps the oil will eat and break down the silicone interior.


Also i did think about routing the catch can directly to the air intake side and bypassing the valves on the PCV, blocking off the vacuum section to the intake manifold. Other people have done this but i really really don't like this setup as no vacuum is pulled on the crankcase any more. The main point of the PCV is to have a vacuum pull out blowby gasses and more importantly water vapour.


There is no vacuum of any use whatsoever on the intake side, especially since that's the point the camshaft cover breather is installed - there will be no pressure difference between the 2 if you install your pcv outlet to there so nothing will pull the gasses out of the crankcase - they will only be forced out when the engine is under load / on boost.


Usual driving patterns mean the engine spends the majority of time not on boost but in vacuum - so you can't rely on high crankcase pressures resulting from boost/loaded engine running to properly evacuate the crankcase. The result of bypassing the vacuum side of the intake manifold that's used to pull the waste gasses and water vapour out is that your oil will turn to sludge, with water vapour and combustion gasses contaminating the oil far more quickly - necessitating frequent oil changes and increasing the chance of corrosion inside the crankcase.


The way i have connected the catch can preserves the vacuum pull on the crankcase, with the catch can catching the oil vapors.


A final picture of the can in place with everything reassembled:

[ope126]

Great write up, I hope all works well for you!
Does the engine cover fit back on now?

[blower]

Nope! - engine cover doesn't fit anymore, but I stopped using it some time ago anyway as they have a tendency to trap heat and overheat coil packs.

[Mk R]

Awesome writeup blower, great pictures too!

[rygreen93]

Just what I needed!!! Thanks Blower.

Ordering my Wossner pistons this week. About 6 weeks without my car now hopefully a couple more weeks and I will have it back.

I will definitely be fitting a catch can.

[The_Hawk]

I have a Forge cold air intake on my 118TSI and swapped it out for the stock airbox recently and noticed a little bit of oil where the airbox meets the plastic pipe (near the green arrow). I figured this was coming from the pipe with the blue arrow given that's where it joins and had been considering installing a catch can... I hadn't really looked into it in any detail and didn't realise that wasn't the primary vent...

Fast forward a little while and I took off that bendy pipe and noticed a decent amount of oil buildup at the red arrow and got far more interested in an oil catch can, started searching found this thread. This really is a brilliant write up!




So my questions.

How is it doing a couple of years on?
Is there any reason (or way) to join in that second pipe (blue arrow)?
Any other advice you might have before I undertake this little job?

Your mounting location looks like it will be the go, although if I go back to the forge intake it takes up far less space than the stock airbox so that might be a little more accessible, although I will see soon enough.

Plenty of nice eBay options too:
JDM Alloy Black 1L Oil Catch Tank Can with 9mm or 15mm Fitting (Complete Kit) | eBay

New Billet Aluminium Baffled Engine Oil Breather Catch Tank Can Reservoir Black | eBay

Including this one with an extra input port for that second line:

Racing Car Baffled 3-port Oil Catch Can/Tank/Air-Oil Separator 0.4L/400ML | eBay

[The_Hawk]

A short five years later and I've finally gotten around to this little project

A trip to a couple of U Pick wrecking yards and many many Golfs later I managed to find exactly ONE vent hose assembly, although it's broken (like everyone including mine) with that back pipe broken. That back bit was completely missing on the wreckers, but easy enough to hook up to what I have.

Grand total of $11! + $2 x 2 for the two wrecking yards I went into.



The plan is to make up the various fittings so I can keep my car in working order and swap in the bits when I'm ready and have an option to put it back to stock should I ever need to. I'm thinking of outsourcing this bit to the local Pirtek.

I've also picked up a baffled catch can from AutoBarn which should do the trick. $100 from the local store seemed reasonable enough for this.



Once done, it should look just like the pictures above... watch this space.