oil catch tank

[red vtec]

Hi,

Is there a guide on how to fit one? I was speaking to an owner at Hethel yesterday (Red Turbo had come down from Scotland, Hi if your on here, also had 300sport wheels ) and he was recommending that it was a good mod, he showed me his installation. But me being me I can not remember the plumbing of it.

[Quicker]

http://www.lotusespritworld.com/EGuides/EM.../CatchTank.html

[red vtec]

God. I'm uselees at finding bits on there!! I had a look in mods part of the site, thanks

so its not needed to feed that pipe back to the airbox? i can just feed to the catch tank? there is then no pipe back to the air box? i'm going to make my own and save some cash.

Edited September 24, 2007 by red vtec

[bzguy]

God. I'm uselees at finding bits on there!! I had a look in mods part of the site, thanks

so its not needed to feed that pipe back to the airbox? i can just feed to the catch tank? there is then no pipe back to the air box? i'm going to make my own and save some cash.

oil catch tank shouldn't cost too much from Ebay

[Dermot]

The idea of a catch tank is that you don't vent the dump oilmist back to the airbox.

[Quicker]

normally - the crankcase venting goes back into the intake for emissions. on supercharged ot turboed vechiles the increased crankcase pressure and intake suction will cause more oil to be sucked up out of the engine and back into the intake.

You normally place the catch can in-line of the crankcase venting line - so the air still goes from the crankcase into the airbox - but passes through the catch can first and has the oil removed.

[red vtec]

normally - the crankcase venting goes back into the intake for emissions. on supercharged ot turboed vechiles the increased crankcase pressure and intake suction will cause more oil to be sucked up out of the engine and back into the intake.

You normally place the catch can in-line of the crankcase venting line - so the air still goes from the crankcase into the airbox - but passes through the catch can first and has the oil removed.

Thats what I was thinking that it must act as a filter? otherwise I cannot see why the manufacturers would have piped to the airbox in the first place. I was going to make mine from an old aluminium bottle, and some brake pipe fittings and wire wool. The pipe will feed in on one side low, the wire wool will be packed in the can to catch the oil mist and then the pipe will feed out of the top back into the airbox taking the clean air. I may as well pump the air back into the airbox as the can obvioulsy has to vent or it will blow up. How does that sound?

Edited September 24, 2007 by red vtec

[Quicker]

in the US - you must vent the crankcase back into the intake to remain emissions legal, you can't dump it the air.

The older style cans were exactly what you described - stainless wool in the can to seperate the oil. However after time, heat and oil, little bit of wool would break free and end up in the intake...

The modern ones use two different methods:

- baffles the attempt to route the air around in the can enough, cooling it, and seperating the oil - these are all over e-bay

- in-line filters - like what is used on air compressor lines - which do a great job and very cheap

Edited September 24, 2007 by Quikr

[red vtec]

Thanks for your help. I'll have alook at ebay. I had seen a DIY one on another site but if you risk the wool breaking up I'll give it a miss!

[Dermot]

Lotus plumbed the dump vent pipe back into the airbox as a cheap method to meed global requirements. They put an oil separator in line but it is not 100% effective. Oil mist in the inlet is really bad on turbo engines as it increases the tendency for the engine to knock. Look in the air intake ducting, most of the older cars will have pools of oil collecting in there.

Of course a catch tank has to be vented otherwise you pressurise the sump. A 100% effective catch tank can of course recirculate the air back to the inlet but they are not. I vent my catch tank to air via a breather filter, it is up to you what you do.

[Jonathan]

Done a fair bit of work on this myself.

1st option was a catch tank - the oil level stick (notice how I avoided saying the dip stick as not to be confused with the owner) kept blowing out showering engine oil all over the lip.

2nd I opened the ports on the tank to about 13mm diameter - any less than that and the increased turbo engine crank case pressure cannot be vented at high rpm quick enough.

Prob with that is as the pot filled up the back pressure on the system increased and again I got oil level stick lift (but no spray).

Essentially you should plum the exhaust port of the catch tank to the intake again as this will provide a vacuum (when the turbo runs) to help suck the fumes through and reduce crank case pressure.

Currently I am running a 7/8" pipe out of the breather port to a filter and it's STILL over pressurising slight - It may be a weak piston ring (have to do a compression test sometime). The filter on the end sits ontop of the engine under tray so when the C service is done the oil collected is wiped away, nothing is dropped on the road that way. The level stick is still poking up a bit under high and sustained boost (ie prolonged 5th gear loads of welly sessions).

On the race car I am going for a larger tank (which is easyier to fit becuase I dont have a trunk/boot to worry about) but I will be using a larger diameter pipe and bigger filter to help reduce the crank pressure.

Just my findings.

[Glyn Harper]

I have my old catch tank up for grabs if anyone wants to offer me

[Jonathan]

Had a chat with one of the engineers at Lipscomb and he was of the opinion that venting it was perfectly OK - so we're off for a compression test sometime soon as mine might be having some internal probs, we'll see.

The filter I have goes right down into the tray so when the belts are changed you just clean the crud off and away you go again.

Using 7/8" copper pipe helps reduce any back pressure - the filter is 25mm inlet as well - came to about

Edited September 26, 2007 by Jonathan

[Artie]

I just got a nice catch tank off ebay for $30 with shipping. I too had vented the crankcase vent and capped off the inlet on the airbox for the oil line. The problem I developed was a lot of oil mist covering junk under the car, like suspension and such. I will post a guide to what I got, how I installed it etc. I plan on putting a K&N cap filter on one inlet and a breather hose from the crankcase filter/air seperator to the can(probably use clear vinyl tube so I can inspect it regularly.

Artie

[bzguy]

I have my old catch tank up for grabs if anyone wants to offer me