Author Topic: 1.6 Turbo Diesel - Oil Catch Can Project - UPDATED  (Read 4801 times)

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Offline The Bun-yip

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1.6 Turbo Diesel - Oil Catch Can Project - UPDATED
« on: December 22, 2010, 08:55:18 PM »
Introduction

I have been asked a couple of times for details of my Oil Catch Can or Tank project for my 2006 Mazda3 1.6 Diesel. It has taken me far too long to get around to it so I can only apologise to those I have kept waiting.  I needed to take some after the event photographs and produce a few sketches to illustrate what I cannot photograph. Hope this is of some help to someone after all this. After completing my project I discovered on the forum that Mazda dealers are fitting what sounds like a catch can from a Mazda6 to Mazda3s with the “oil contamination” on MAF sensor problem. It would have been more expensive to let the dealer do it but not as much fun.

OK the start point for my project was the discovery of oil on the surface of the Paper Air Filter prior to a service that left me wondering how it got there.
See third pic in this post for what I also found. http://www.mazda3forums.co.uk/index.php/topic,3279.msg34802.html#msg34802

The Crank Case ventilation system seemed the most likely source to me in a car with only about 12,000 miles on the clock … unless I had a dodgy Turbo. A routine Oil Level check following the service then revealed that my sump had been overfilled by about a litre. (As usual, I provided the oil. I should not have given the garage 5 L!!!) The oil level was smartly lowered to the correct level.

After the service I had planned to fit a K&N panel filter. When I removed the Air Filter box top I took the opportunity to take a look to see if my MAF was oily. The examination revealed contamination on the MAF and even more of a concern was a quantity of oil pooling in the concertina folds of the MAF to Turbo inlet hose. So the hose and MAF were cleaned. I thought about the near escape I might have had had if the PCV system had forced some of the excess oil out into the input air stream. I had read about the self destruction of diesel engines when they consume their own sump oil as fuel and claims that an overfilled sump can triger it.

The trouble with modern Diesel EGR & Crankcase Ventillation systems

Googling revealed that the EGR + PCV recycling system was a potential risk so far as I was concerned. Although in normal circumstances any oil mist coming through the PCV system should be sucked through the Turbo and supposedly burnt I read of far too many problems in the Air Intake system of high mileage Diesel cars. Inlet Manifolds and Intercoolers clog up with crud formed from the oil and exhaust solids thanks to the EGR system. To avoid this and other problems many Diesel Drivers seek to disable the EGR unconcerned with nullifying its important anti pollution role. Occasional removal of the intercooler for internal cleaning seems to be required in many Turbo diesels. In addition Oil vapour finds its way back upstream to contaminate the MAF reducing its effective life.

These Pics have been borrowed from a VW forum.





I have recently read a report that suggests that VW are now tapping into the exhaust stream for the EGR system after the DPF. An innovation that I anticipate will prove highly beneficial.

Back to my efforts... Not being an expert on fluid mechanics I can only guess at how the MAF is contaminated. There is plenty of discussion in the various Forums to suggest it is a very common problem in many Diesel engines including our PSA/Ford 1.6 Turbo. It seems to me that stopping the engine and shutting down the Turbo could result in some turbulence inside the air filter/MAF to Turbo connection tubing. The result may be some temporary back pressure flowing out through the Air Filter to atmosphere carrying oil vapour from the PCV to contaminate the MAF and produce the small amount of contamination I had found on the surface of my Paper Air Filter. As I plan to keep the car for several years I decided that a modification to prevent problems could be a good idea.

Finding a solution

Through Google I learnt that while sophisticated filter systems such as the ‘Mann-Hummell - Provent 200’ are available to insert into the  PCV to air inlet tubing they are too expensive for my tastes.   http://www.mann-hummel.com/company/index.html?iKeys=3.1.180.0.0&cScr=35&rec_no=192 I could see that solution costing over £200.00. I opted for one that cost about £35.00 plus some bits and pieces I already posesed.


Mann-Hummel - Provent 200

Fortunately for me removing oil from the PCV output is common in petrol engines using some variation of an “Oil Catch Can or Tank”. Several forums provided ideas for making the Catch Can effective. Lots of variety to inspire from one built from copper pipe and and a recycled Baked Bean Tin (True) to an elegant multi chamber CNC machined Catch Can tailored to fit the available space in an engine compartment. The many simple off the shelf systems are often advertised as being machined from solid aluminium which I guess would provide some thermal mass to help the oil vapour condense. One idea I picked up is to fill the can with wire wool to further encourage oil condensation. I finished up using some stainless steel scouring pads from a supermarket.

My project took a standard Catch Tank or Can sourced from eBay and modified it to incorporate the ideas I had encountered which aim to increase effectiveness. The can I chose is rectangular in section with a detachable lid to make it easier to fit my chosen modification. (Note these catch tanks can be supplied with various sizes of pipe connection nipple. Diesel Engines require the larger size of 15mm.)


My eBay purchase

Improving Modifications?

Rather than pass the blow-by gases and Oil Vapour through a simple chamber I would attempt to cause the flow to pass through my Stainless Steel wire wool and hopefully leave any oil in the ‘can’. Many Catch Can installations seem to mount the ‘can’ on the Firewall behind the engine and run piping to the PCV outlet and Turbo intake. As diesel engines can move significantly on their mounts when the engine stops suddenly I decided to follow the example in the VW Tdi forum and hang my can from the engine itself and so reduce the movement to which the connecting piping would be subjected. I also replaced the small (easy to drop down behind the engine) drain plug supplied with a 1/8 BSP tap so as to make maintenance easier. Fortunately the can was manufactured with 1/8 BSP tapped holes for the sight tube and drain plug. :)
This ‘Mini Brass Ball Valve 1/8"bspp’ was also sourced from eBay.


The Tap

My internal modifications to the can looked something like this sketch.


Exploded Can

The lid was removed and modified with a piece of B&Q ‘L section’ aluminium edging strip cut to shape and Screwed/Araldited between the two Inlet/Outlet holes. A second piece of the same strip was mounted at the top of the can splitting the top section of the can into two chambers. On reassembly I used some liquid gasket to reseal the lid and the join between the two part divider. The lid was also reversed to place the can mounting holes for the bracket in front underneath the hose nipples and the Sight Tube and Tap on the easier to access LHS after final mounting.


Can Components.

To mount the can in a suitable space where any engine movement would not cause a problem I chose the void behind the engine above the LH end if the common rail. This required fabricating a bracket that could be attached to the existing mounting that is used to provide the fixing for the rear LH end of the engine cover.


Bracket Drawing

The bracket was made from some scrap steel sheet left over from the days when I welded bits of steel to my Ford Escorts every time an MOT was due. ::)  In order to avoid buying a bit of steel bar for the horizontal section of the bracket I made a composite one. A strip of the steel sheet that would not have supported the can on its own was bonded to some of my ‘L section’ aluminium edging strip with Epoxy Adhesive. It is amazing what ideas you remember from working in the Aerospace Industry 40 years ago. :) The vertical mounting piece for the can was simply screwed and Araldited to the composite beam. A tidy up with a file when complete and a coat of Hammerite finished it off.

Installation

A couple of holes drilled in the Engine Cover support bracket were used to fix some metal screws in place and act as studs on which to mount the bracket for the Catch Can. I also cut the heads from some screws and fixed them into the can body with some Loctite and lock nuts. (I always had a talent for over-engineering) To connect the diverted PCV output via my Catch can I used heater hose as others have done rather than invest in expensive silicone hose much favoured by those who like to add ‘bling’ wherever possible. The heater hose inside diameter was too large for the catch can nipples but fitted snugly over sleeves fitted to the nipples that were simply short pieces of the plastic pipe supplied with the can. They were secured with Jubilee clips. To join the Heater hose to the original PCV to Turbo inlet hose I simply cut that hose and found it fitted snugly over the end of the heater hose. A couple of 15mm copper Yorkshire Straight fittings extracted from my Plumbing ‘Bits & Bobs’ box inserted into the ends of the heater hose provided a suitably rigid reinforcement to tighten the Jubilee clips against. Before use I heated the fittings to remove the solder rings to prevent any risk of loose debris finding its way into the Turbo Intake etc.

Installation started with fixing the modified Catch Can to the fabricated mounting bracket and then attaching it to the engine cover support bracket and adding the hoses. The result looks like this.


Finished

From Left

From Right

Mounting Bracket

Piping connections

The last task was to cut some foam from the underside of the Engine Cover to allow it to be refitted over the new hoses. As you can see my project is more Heath Robinson than good engineering. It does seem to be functional.

Finally

Now that I have clocked up about 3500 miles since the modification I can report that it does not seem to have achieved much. There is no sign of liquid oil in the sight tube although it is now stained and opening the tap has not drained any oil. So perhaps the majority of my oil contamination resulted from the overfilling of the sump and my Catch Can is not good enough to catch any slight Oil Vapour contamination coming from the PCV. So it is possible that my mod may not have done anything other than give me a chance to use some long dormant metal bashing skills.

On the other hand I shall be very happy if I have what proves to be a suitable protective device in my engine’s Air Intake System. Hopefully, by removing the oil from the Oil + Particulate matter mix I  might avoid the blocking of my Inlet Manifold and Intercooler with the amount of ‘crud’ illustrated in the VW TDi manifold at the start of the post. Of course modern low sulphur fuels may be clean enough to avoid the “crud blockage” problem anyhow. Time alone will tell if it will protect my MAF sensor. A recent inspection revealed no obvious sign of MAF contamination.

I should know for certain when we have some warmer weather and I clock up some reasonable mileage.
« Last Edit: January 23, 2011, 05:06:17 PM by The Bun-yip »

Offline Willpower

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Re: 1.6 Turbo Diesel - Oil Catch Can Project
« Reply #1 on: December 22, 2010, 09:44:01 PM »
Stickied
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Offline The Bun-yip

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Re: 1.6 Turbo Diesel - Oil Catch Can Project - UPDATED
« Reply #2 on: January 23, 2011, 12:08:08 PM »
The Mark II Catch Can

One of my original concerns when planning the project was the selection of suitable size piping. It is pretty obvious that should a size that is too small be used it could generate Back Pressure that might not do the PCV valve and crankcase pressure any good. There are scattered Forum reports of people having problems which they blame on using narrow pipework for Diesel Catch Cans. Initially I hoped that by selecting a pipe size to match the larger connection nipples I would be OK even if that was smaller than the existing CCV outlet hose. So, for the MarkI, I used 16mm Internal Diameter hoses.

UKZMISR another Forum member contacted me to discuss the oily PCV output problem. We exchanged a number of PMs. He has opted to have Mazda’s solution taken from a Mazda6 fitted to his Mazda3 1.6 Diesel. One of the interesting pieces of Information he came by is a Mazda3 service bulletin that applied to early (Euro3 non DPF) examples of the 1.6 Diesel. As part of the strategy to address the excess oil in the CCV hose the internal diameter was increased in subsequent production. So I decided to bite the bullet and replace my hoses with something as near as possible to the ID of the current CCV hose. Crude measurement suggested that I should aim for about 22mm.

Now if I was going to use 22mm ID hose the thought occurred that it would be better if I did not create an obstruction by narrowing the hose down onto the 15mm inlet ports on my Catch Can. So I set out to modify my Catch Can to use 22 mm ports.  Dismantling my Mark I Can revealed that a quantity of water and oil had been collected in the can but the outlet port showed signs of oil contamination. All the oil vapour had not been condensing in the Can.

Because of the size and position limitations imposed by the existing port holes I decided that I would not be able to use larger tapped holes for the ports and opted to mount my replacement ports in two new holes fixed in place with some “JB Weld”. (A steel reinforced epoxy adhesive suitable for high temperature applications.) The inlet port was enlarged (filed) with its centre moved to the right. This meant that the adjacent hole could not be used as the resulting hole for a 22mm connector would be too close to be able to affix the hoses. So the redundant hole was sealed with JB Weld and a new exit port inserted in the top of the lid. It too was fixed with JB Weld.

The inlet port was cut from a section of standard straight 22mm silicon hose conector. The outlet port was assembled from a standard domestic plumbing 22mm right angle connector reinforced and extended slightly to provide a raised connection lip by inserting a section of the silicon hose connector cut from the one used for the inlet port. The insert was fixed with JB Weld instead of the usual solder for that fitting. After assembling in stages to make the use of the epoxy easy the top was given a coat of paint to tidy its appearance.


Underneath view of modified Catch Can Top.


Completed modified Top


Catch Can Body ready for reassembly. A couple more stainless steel scouring pads were added to the original three to help condense more of the oil.

The 22mm hoses needed some flexibility as the pipe run would not be perfectly straight. In addition I did not want the hose wall to be too thick and create space problems. Fortunately eBay came up trumps with some suitable 22mm hose. I have used 22mm silicon Vacuum Hose which because it is not constructed with fabric reinforcement layers is reasonably flexible and has an acceptable 3mm hose wall thickness. It is also cheaper than the rigid reinforced hose. To connect the Catch Can hoses to the original CCV hose I used standard domestic plumbing 22mm straight Yorkshire Connectors having first removed the solder rings. Standard Jubilee clips were recommended by the pipe supplier for use with this type of hose.


Reassembled and connected.

Now all I have to do is run it for a few months and see if I have succeeded in stoping CCV oil vapour fouling my MAF. I also cleaned the MAF, MAF-Turbo inlet hose and my K&N panel filter so that I start with a clean system.

Offline Willpower

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Re: 1.6 Turbo Diesel - Oil Catch Can Project - UPDATED
« Reply #3 on: January 23, 2011, 05:00:33 PM »
If any member wishes to discuss this procedure or has any questions, would you please start a new thread to avoid contamination of this sticky.

Thankyou
Willpower
Look at life through the windscreen, not the rearview mirror.
2004 Winning Blue 2Ltr Sport Saloon.  Laser Blue Main beams.

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Re: 1.6 Turbo Diesel - Oil Catch Can Project - UPDATED
« Reply #3 on: January 23, 2011, 05:00:33 PM »