Found this in my - GT-R Register - Official Nissan Skyline and GTR Owners Club forum

Peter · 18th November 2002, 12:27 AM

catchtank!

First time of emptying, after a few months and 2 or 3 track days. The yellow liquid at the bottom isn't flammable so I'm guessing it's water based....?

Anybody else done their's, does this look a similar type of gunk?

DCD · 18th November 2002, 08:45 AM

Damn thats a lot of gunk!!

Looks like a pint with lots of head!

Peter · 18th November 2002, 08:57 AM

Not sure it would go well with a packet of crisps though Dino.

The grey 'head' is an oily emulsion so I presume that water vapour is present in the crankcase presumably as a result of combustion and blow by....?

There's about 1/2 litre in total so not too much. I've heard of several guys on here having to empty their catchtanks after a single day on track....

dan0h · 18th November 2002, 09:33 AM

I'd be very surprised to find any water vapour in the crankcase ventilator system ... Oil and water should never really meet in any engine.

Unless I'm a total gibbering muppet I'd say something doesnt look quite right there, check out that head gasket ... hopefully its nothing sinister (ie. Cracked head/Block).

I hope for your sake I'm completely wrong ... but I'd be quite concerned if I'd just got that out of a catchtank.

Cheers,

Dan

Peter · 18th November 2002, 09:49 AM

She never uses a drop of water Dan so no worries there. As I understand it, and I'm sure somebody will confirm this or correct me (Mycroft, Mark, Gary..?), when running higher boost, you get piston blow by whereby some of the combustion gases get into the crankcase. By their nature, these gases will contain water vapour so I presume that when these enter the catchtank, they condense and get caught there. This would also explain how people get petrol in their catchtanks which I've heard has happened to at least two of the guys on here.

I'm interested to know what others have found in their tanks.

Mycroft · 18th November 2002, 11:22 AM

As I don't 'know' your car and Gary or Mark do (they may even have serviced it) I do tend to see this sort of thing as being Gary and Marks 'province, but as far as I'm concerned this looks OK, if the timescale and use is as you say, but I would 'monitor' the tank very closely for the next few months to be 'safe'.

What I will add is that there is some evidence there of driving a little too quickly before the car has fully warmed or driving the car on lots of short journeys (one or t'other). I say this because I remember reading somewhere that more than 10% water content in a catch tank is indicative of this, but I have no direct experience of Skyline engine tuning.

Peter · 18th November 2002, 11:46 AM

Quote:

Originally posted by Mycroft
What I will add is that there is some evidence there of driving a little too quickly before the car has fully warmed or driving the car on lots of short journeys (one or t'other).

Definitely not the former but the latter is correct of late.

Thanks.

Has nobody else ever emptied their catchtank?

SteveC · 18th November 2002, 11:59 AM

Dirk was telling me about when he emptied his before Brands.

Said there was a layer of water, then oily type residues of various colours. kind of like a tequilla sunrise for a petrol head !!

I fitted the breather to mine the other day so there are no smells at all now.

It vents out the back so people behind can have the pleasure.

/Steve

RonS · 18th November 2002, 12:24 PM

Yeah... seen a mate drinking this, it's combination of guinness and lager, try it Peter if it tastes like engine oil and water, that'll be it

RonS

dan0h · 18th November 2002, 02:14 PM

Quote:

Originally posted by PeterE
...when running higher boost, you get piston blow by whereby some of the combustion gases get into the crankcase. By their nature, these gases will contain water vapour so I presume that when these enter the catchtank, they condense and get caught there...

Fair enough, I'm just surprised that its that volume of water, seems like it would take an amazing amount of vapour to create that sort of level of water. I would have thought the heat inside would bake any moisture out long before it gets into the catchtank ... Mycroft as always has the wisest words

Again, just seems a lot of water

I stand corrected

Let us know any developments though...

Cheers,

Dan

Peter · 18th November 2002, 02:19 PM

Quote:

Originally posted by dan0h
I would have thought the heat inside would bake any moisture out long before it gets into the catchtank ...

Where to? The vapour can't escape the engine, no where to go until the vapour exits the breather system, i.e. into the catchtank. Without a catchtank, it all gets sucked into the intake.

Ron,

Where you been hiding? I'll have a sip later, maybe bottle it for real petrol heads....

Peter.

lightspeed · 18th November 2002, 02:23 PM

Also when the weather is cold and the car left standing (typically overnight) condensation forms on the inside of the engine.

This will end up in the catch tank as well as any water vapour from blow-by.

This time of year it will really make a difference.

Peter · 18th November 2002, 02:27 PM

Yes, good point, hadn't considered that...

dan0h · 18th November 2002, 02:38 PM

Quote:

Originally posted by PeterE
Where to? The vapour can't escape the engine, no where to go until the vapour exits the breather system, i.e. into the catchtank. Without a catchtank, it all gets sucked into the intake.

I'll get my coat

Good point again... Ditto lightspeed...

SPOOLIN · 19th November 2002, 07:58 AM

Mine looked similar to that when i emptied it (had to replace parker globe which is behind catch can). Although mine was a little creamier and i didn't let it sit so i could separate. It did smell strongly of fuel.

Does your engine only vent to the catch can through the 2 breathers on the top or do you have bundy (ally tube) coming from the sump aswell?

Hope this helps

Lee

18th November 2002, 12:27 AM	#1 (permalink)
Peter GTR Register Member Join Date: Jun 2001 Location: East Sussex. Posts: 9,029	Found this in my catchtank! First time of emptying, after a few months and 2 or 3 track days. The yellow liquid at the bottom isn't flammable so I'm guessing it's water based....? Anybody else done their's, does this look a similar type of gunk?

18th November 2002, 11:59 AM	#8 (permalink)
SteveC GTR Register Member Join Date: Jul 2001 Location: West Sussex Posts: 1,836	Dirk was telling me about when he emptied his before Brands. Said there was a layer of water, then oily type residues of various colours. kind of like a tequilla sunrise for a petrol head !! I fitted the breather to mine the other day so there are no smells at all now. It vents out the back so people behind can have the pleasure. /Steve __________________ tdi

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18th November 2002, 08:45 AM	#2 (permalink)
DCD GTR Register Member Join Date: Jun 2001 Location: Tokyo Posts: 9,336	Damn thats a lot of gunk!! Looks like a pint with lots of head!

18th November 2002, 08:57 AM	#3 (permalink)
Peter GTR Register Member Join Date: Jun 2001 Location: East Sussex. Posts: 9,029	Not sure it would go well with a packet of crisps though Dino. The grey 'head' is an oily emulsion so I presume that water vapour is present in the crankcase presumably as a result of combustion and blow by....? There's about 1/2 litre in total so not too much. I've heard of several guys on here having to empty their catchtanks after a single day on track....

18th November 2002, 09:33 AM	#4 (permalink)
dan0h GTR Register Member Join Date: Jul 2002 Location: Essex Posts: 2,004	I'd be very surprised to find any water vapour in the crankcase ventilator system ... Oil and water should never really meet in any engine. Unless I'm a total gibbering muppet I'd say something doesnt look quite right there, check out that head gasket ... hopefully its nothing sinister (ie. Cracked head/Block). I hope for your sake I'm completely wrong ... but I'd be quite concerned if I'd just got that out of a catchtank. Cheers, Dan

18th November 2002, 09:49 AM	#5 (permalink)
Peter GTR Register Member Join Date: Jun 2001 Location: East Sussex. Posts: 9,029	She never uses a drop of water Dan so no worries there. As I understand it, and I'm sure somebody will confirm this or correct me (Mycroft, Mark, Gary..?), when running higher boost, you get piston blow by whereby some of the combustion gases get into the crankcase. By their nature, these gases will contain water vapour so I presume that when these enter the catchtank, they condense and get caught there. This would also explain how people get petrol in their catchtanks which I've heard has happened to at least two of the guys on here. I'm interested to know what others have found in their tanks.

18th November 2002, 11:22 AM	#6 (permalink)
Mycroft Banned Join Date: Apr 2002 Location: Up someones nose, apparently Posts: 3,561	As I don't 'know' your car and Gary or Mark do (they may even have serviced it) I do tend to see this sort of thing as being Gary and Marks 'province, but as far as I'm concerned this looks OK, if the timescale and use is as you say, but I would 'monitor' the tank very closely for the next few months to be 'safe'. What I will add is that there is some evidence there of driving a little too quickly before the car has fully warmed or driving the car on lots of short journeys (one or t'other). I say this because I remember reading somewhere that more than 10% water content in a catch tank is indicative of this, but I have no direct experience of Skyline engine tuning.

18th November 2002, 12:24 PM	#9 (permalink)
RonS New Users Join Date: Dec 2001 Location: West Sussex Posts: 806	Yeah... seen a mate drinking this, it's combination of guinness and lager, try it Peter if it tastes like engine oil and water, that'll be it RonS

18th November 2002, 02:23 PM	#12 (permalink)
lightspeed GTROC Member Join Date: Jul 2002 Location: South-west Posts: 1,812	Also when the weather is cold and the car left standing (typically overnight) condensation forms on the inside of the engine. This will end up in the catch tank as well as any water vapour from blow-by. This time of year it will really make a difference.

18th November 2002, 02:27 PM	#13 (permalink)
Peter GTR Register Member Join Date: Jun 2001 Location: East Sussex. Posts: 9,029	Yes, good point, hadn't considered that...

19th November 2002, 07:58 AM	#15 (permalink)
SPOOLIN GTR Register Member Join Date: Sep 2002 Location: Sth Australia Posts: 18	Mine looked similar to that when i emptied it (had to replace parker globe which is behind catch can). Although mine was a little creamier and i didn't let it sit so i could separate. It did smell strongly of fuel. Does your engine only vent to the catch can through the 2 breathers on the top or do you have bundy (ally tube) coming from the sump aswell? Hope this helps Lee