Breather / Catch Tank system

[smckeown]

I'm looking to optimise the system on my Peugeot 205 sprint car, and replace my existing too small catch tank.

I found a good article on the burton power website with some good information. http://www.burtonpower.com/technical_1/ ... ystem.aspx

Showing an example race engine breather setup:



It raised a number of questions and provided some guidance also.

The article also advised that you can get excessive oil coming through the cam cover breather if located directly above the cam (to which my 8v one is an example) without some form of shield.



So on this basis, I should either fit a shield to the inside of the cam cover, or get it moved tothe end like the mi16.

Here is my existing setup (not far from the OE setup)



It now seems the cam cover is feeding excess oil back to the oil filler hose. I assume it's not venting air (or aireated oil) as otherwise it would join the oil fiiller at the top in order to vent. So my first question is what's the bloomon point of that then, as the head has oilways back to the sump?

It seems outlet in blue is the only actual breather hole; i'm assuming this because it's the only hose that joins the oil filler tower at the top. Is this correct ?

So what about these 2 proposed systems:





As you can see from both proposed solutions i'm not draining back to the sump. I have seen catch tanks that are a 2 part system, one compartment with de-arieated oil to go back to sump, and another section with vapour/water/gunk to be drained

[smckeown]

The background to this thread, and a previous one regarding crank case pressure is I've had very bad luck with this engine (built by 2 different engine builders) and for the last 3 years has not lasted more than 1 track day (and i'm no damon hill) without significant work needed afterwards, like new bottom end bearings. I'm aware the first engine was havibng excessive crankcase pressure due to a broken ring. But i'm thinking that it's an inefficient breathing system that was the cause. I cannot believe it was installed incorrectly as the engine builder is reputable.

Since rebuild by another engine builder, well the car has never reached it's power potential, or been reliable.

So I'd like to try an eliminate/enhance one of the aspects that have been constant throughout my ordeal.

More recently, when I was running in the rings a few weeks ago, my oil catch tank (about 1 litre in capacity) filled up completely with what looked a very poor resemblance to oil. It was very light brown in colour. It was setup like the 'existing setup' picture above, and did not have a filter/breather installed on the catch tank at the time.

So I'm pretty paranoid about this area now, and would appreciate some experienced advice.

thank you
Sean

[pacman]

So you filled up 1 liter breather tank with light brown oil substance (mayonnaise?)...
Sounds like water in the oil. As described, it´s more than just normal internal condensation.
Blown headgasket? Are you loosing cooling water?

//PeterC

[smckeown]

I would be extremely surprised with HG failure, i'm convinced there's another reason. Maybe the main one is that i've not been running with a filter on the catch tank.

The engine is not very old, maybe 2k miles since rebuild, professionally rebuilt, has copper head gasket, wire ringed liners, not losing coolant..changes of HG failure are low i'd hope.

Changed the oil yesterday for the first time since new rings, the oil was very black indeed, but so signs of water. Next time i'llremember to let is sit overnight and have a jamjar ready for the initial drainage to see if there's any coolant. Just read that tip here http://www.carbibles.com/engineoil_bible.html

[smckeown]

OK i've read the burton power guide again and looking more closely at the arrows highlighting flow, I now see what the ideal setup is, and what the problems are with my current setup.

Here's my setup again (enhanced the diagram to show the flows)



The problems with my system are:

1 - The breather from the cam cover is unbaffled. So with the breather being directly above the cam at high revs (OE rev limit is 6300, my engine is built to withstand ~8200) that's going to spit out too much oil, so that needs to be modified with a baffle, or moved.

2 - My cam cover breather route is like spagetti junction. It firstly travels downwards (that's a no no according to the burton guide, i.e. should be horizontal or on same level) then joins the oil filler pipe almost at the block then needs to travel upwards to then travel out from the oil tower to the catch tank.

3 - Both the block and cam cover breather both join at the oil tower and that's a single small hole outlet to the catch tank, so a possible situation (along with 2) of insufficient breathing.

So the resolution seems to be:



1 - Proposed solution 2 above (which is a copy of burton power suggestion with some additions needed/checked). In summary this is a breather from the cam and a separate breather from the block, with an additional catch tank breather/filter

2 - Baffle the cam cover breather

3 - Raise the catch tank to be horizontal to the cam cover

The mocal oil catch tanks seem to fit the bill perfectly. They don't have the option to drain back to the sump, but I don't want that option anyway.

thank you
Sean

[Rich Ellingham]

Hi, so the plan is the same as what I have in my Fiat side eixt with baffle on the head to the catch tank and block to catch tank - although the Fiat has a small device to reduce the oil vapour in the gases going to the catch tank (GC please correct if I'm wrong).

The only thing I will say about the mocal tank is the plastic cap has a fine thread which becomes problematic are opening an closing a number of times, the pressed alluminium thread in the tank abrades the thread a bit, I find mine takes a bit of getting on. When the engine was damaged it breather heavily this vapour did no condense well inthe tank and ended up blowing out of the top of the tank which made a mess and ended on the drive shaft then on the tyre. You can drain it back to sump if you wish via the tapping on the bottom anf the side entries are left right hand specific, but can be change to a 90 degree inlet fitting - think automotive being who they are, are well equipped to sell you alternative fitting in addition, you could probably get a fitting to replace the cap to a breather filter.



a little clearer here on the 08 engine


Regards

[smckeown]

Thanks for the update, it's good to know more people have implemented the breather system as per the burton power article.

I was reading another book last night from Graham Bell and it was good to get his thoughts on breathing. One of his concerns is matching breather outlets, such as the one on the block, with the fitting on the catch tank.

So I have been looking at all the catch tanks generally for sale and none match my block or cam cover breathers very well..far too small generally.

There are plenty of places that fabricate custom catch tanks, with no significant expense (sometimes cheaper than the manufactured ones), so i'm waititng to hear back fro ma few enquirees.

Thanks for the warning on the mocal breather top

Sean

[smckeown]

Another update on my research....

I was looking into oil seperators in conjunction or in place of a catch tank. Of all the informed sources I read from they all stated that the return pipe from the de-aerieted oil should go to the bottom of the sump/oil level.

So where does the oil return go from the cam cover on the standard setup ? to the block, therefore at the top of the oil level. Thanks peugeot! A double whammy being they didn't baffle the 8v cam cover outlet so plenty of aereated oil could flow down to the block, especially on higher reving engines.

So rather than going to the expense of tapping the sump, i'm sticking with my design of not having a return from the catch tank into the block. It's less road friendly/needs more maintenance, but for a track/sprint/race car that's not a concern

I had a secondary idea regarding the oil filler modifications I am contemplating. On the basis people like A Graham Bell recommend more than 1 crankcase breather in times of oil surge, I was thinking rather than blocking the oil filler outlet off, I could use it as another breather. Also as you increase the power of your engine increses, increased breathing is a must. They are similarly positioned in the crankcase as per here

If I remove the existing oil filler tower and have a filler cap fabricated into the cam cover. I have an additional crankcase outlet available for additional breathing.

Here are the pics of the 2 fittings:

blue = oil filler
yellow = crankcase breather





So here's a picture of my latest proposal:

[SteveninNI]

your last diagram is how i do it on my clients engines.

Should work fine.

[smckeown]

your last diagram is how i do it on my clients engines.

Should work fine.

That's good to hear, which version of my diagrams, the 2 pipes (head/block breather) to catch tank, or 3 (oil filler as well) ?

thank you
sean

[SteveninNI]

the last one with the 2 from block and new baffled one from cam cover all into catch tank.

Last Super 1600 Saxo I did, I had to add an additonal one from block into cam carrier then another from cam carrier to catch tank, also had to add breather from sequential gearbox

[smckeown]

the last one with the 2 from block and new baffled one from cam cover all into catch tank.

Last Super 1600 Saxo I did, I had to add an additonal one from block into cam carrier then another from cam carrier to catch tank, also had to add breather from sequential gearbox

Thanks ever so much, it's great to get race proven examples, and to help stop me making a BANNED out of myself :D

[smckeown]

I'm now looking into the next evolution of this design.

Essentially i'm looking to adapt it so there is a return tothe sump.

Firstly I read that you want the return to attach to the sump below oil level, and that you may want a one way valve. I can imagine putting the return at the front of the sump without a one way valve may cause issues as the oil under hard beraking would sheet up the return pipe.

So is there any more experience from people in this area ?

Secondly fitting the union to the sump. Should I weld a boss to the ali sump, or get a self sealing union ? I'm concerned about crank clearance with a self sealing unit, as well as lack of lingevity of the seal.

any input appreciated

thank you
sean

[Guy Croft]

I have exp in this area - on engines working well and badly!

Sorry to cut right across this but no way do you need a drain back to the sump. I have never fitted nor recommended this in my life. Firstly because on an engine where the catchtank is located above the breather vent and which has good ring sealing because there shouldn't be much by way of oil in the tank - ever. A catchtank is really there to allow oil vapour to condense - the droplets are tiny so you shouldn't get much by way of accumulation. So you're stopping them blowing to atmosphere (or over the racetrack).

On a good engine you can get a lot of oil going to the catchtank - straight up the breather hose - and not just vapour - in high G if the sump isn't well baffled or - if the sump is overfilled. Or if you have an accumulator and hook it up wrong it overfills the sump and never draws off. On an engine that's in trouble you can get oil thrown out if a bearing is badly worn. And, naturally, an engine with poor bore-ring sealing is going to chuck oil out all the time.

One reason for not draining the catchtank is that you can get a pretty good idea of how the engine is running by examining the amount collecting in it.

GC

[Uros Piperski]

What about turbocharged engines? Both Dedra and Delta integrale (8v) have a catch tank with drain back to the sump.