Blow-by Oil catch tank

Submitted: Thursday, Jun 23, 2005 at 08:48
ThreadID: 24096 Views:9094 Replies:5 FollowUps:13
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The oil from the top of my Diesel motor, 4.2Tdi Patrol, is routed into the intake after the airfilter and before the turbo compressor. I have noticed that it is coating the insides of all the pipes and presumably the compressor and intercooler quite heavily. The EGR feeds soot back into the intake after the intercooler and it is causing the the soot to build up faster with the oil. I dont think this can be a good situation and have alrady tinkered with the EGR.

I have been looking at options for putting a catch tank between the PCV on top of the tappet cover and the intake piping to remove the oil. There are a number of tanks available at a price from performance stores with various fittings etc. I would like the excess oil to gravity feed back into the sump.

Has anyone done this? What products did you use? How did you plumb it into the system? etc? etc? Any thoughts welcome.

thanks in advance for the astounding insight in your feedback, although in some recent posts it is more like incite especially if you have a kluger!!

JamieMac
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Reply By: Sea-Dog - Thursday, Jun 23, 2005 at 12:12

Thursday, Jun 23, 2005 at 12:12
I have an 80 series landcruiser, turbo diesel and had the exact same problem.. after searching around to see if there was anything on the market I ended up making a catcher up myself.

Basically it is a piece of PVC pipe about 60mm diameter and about 250mm long. I have put a cap on each end and have drilled a drain hole in the bottom which is fitted with a removable bolt to drain the oil over time.
I put the bottom hose (the intake line from the rocker cover) about 40mm up from the bottom with a baffle glued on the inside of the pipe to break the air flow as it comes in.. from the baffle to the top pip (returning to the turbo intake) is filled with a coarse gauze to help filter the air coming through.

I used 17mm heater hose for the lines in and out and went to the local hardware supply store and got hose fittings with threaded backs on them so I could secure them into the PVC pipe securely as they will get bent around a bit putting the pipes on and off etc.
Of course make sure it is all sealed properly and securely or dust may enter and go straight to the motor via the turbo.

I had to have 3 or 4 goes at it until I was happy but now I don't have the puff of blue smoke that I had the morning after a long drive up the highway due to the coated pipes running oil down to the turbo intake overnight.

Hope all this makes sense to you.... it is all fun and games and kept me interested for a few days until I got what I was happy with... painted it all black so it blends in with the rest of the stuff under the bonnet also.

Cheers
AnswerID: 117036

Follow Up By: ColinD - Thursday, Jun 23, 2005 at 15:24

Thursday, Jun 23, 2005 at 15:24
Sea-Dog, I love to hear guys not afraid to have a go and make-manufacture things for themselves. A small suggestion though, you will most likely find that the heater hose will be swelling soon as it will be breaking down because of the oil. You may need to replace it with an oil resistant hose.
Also, as you have no way for the oil to return, if it were to inadveratantly
fill or the vehicles angle alter there is a possibilty that your engine could ingest a quantity of oil causing catastorphic failure. This was a common occurance with the older oil bath filters that were incorrectly filled (over).
Just my two cents,,,,,have a great day,,,,,,,,,,,,,,,,,,,,,,,,col
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Follow Up By: Sea-Dog - Thursday, Jun 23, 2005 at 15:50

Thursday, Jun 23, 2005 at 15:50
you will most likely find that the heater hose will be swelling soon as it will be breaking down because of the oil. You may need to replace it with an oil resistant hose.
Also, as you have no way for the oil to return, if it were to inadveratantly
fill or the vehicles angle alter there is a possibilty that your engine could ingest a quantity of oil causing catastorphic failure.

G'Day Col,

I have considered the hose and am monitoring it as it is a work in progress.

As far as the oil return goes the line placement is very little in difference to the original as I have placed the catch tank on the other side of the brake booster so the lines running in and out are pretty much at the same sort of angles as the original just with a catch tank in the middle. If anything, if this tank was to overfill for some reason and that oil was to be ingested by the turbo intake in any amount it would be because the car is standing on it's head and I will have bigger problems on my hands.

Point taken though, It is something that if tackled without forethought may end in a world of trouble.

I would add though that I have an older style motor with no sensors etc that may be "fooled" by changing these sorts of things and I would be hesitant to play with a newer car unless you are keen and have researched it well.

I don't believe the mod is illegal though as the motor is still using it's own gasses etc and if anything will run cleaner.
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Follow Up By: JamieMac - Friday, Jun 24, 2005 at 08:39

Friday, Jun 24, 2005 at 08:39
Thanks for the feedback Sea Dog I have mad a combined reply below

JamieMac
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FollowupID: 372644

Reply By: ColinD - Thursday, Jun 23, 2005 at 14:22

Thursday, Jun 23, 2005 at 14:22
Hi Jamie, firstly the most likely cause of the problem is an ageing engine that requires rings which is causing excesive blow-by. Secondly to meet ADR the engines own fumes are to be consumed by the engine, so a catch tank would most likely be illegal. Thirdly, tampering with EGR "can" impact adversly with engine performance, as it is an inert gas it is factered into the fuel timing etc.
However, as a factory fix (I think it was a Subaru model) I have inserted sintered bronze filters to the PCV line to combat oil being spat into the air filter.
I would recommend that you modify the baffle inside the rocker cover, in an effort to make the oil fumes condense before they enter the PCV pipe.
Hope this is helpful.......................col
AnswerID: 117059

Follow Up By: ColinD - Thursday, Jun 23, 2005 at 14:32

Thursday, Jun 23, 2005 at 14:32
Sorry, forgot to add that any significant restrictions in the PCV line are likely to cause a build-up of crank case pressure. This will cause oil leaks to appear in the main seals and others.
Also be aware that the position of the PCV is after the air fliter and therefore unfiltered. Meaning that any additions to the line need to be adequately restrained and of a sufficient material that will not breakdown or corrode ie steel wool etc. and end up in your favorite turbo.........col
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Follow Up By: Member - Jeff M (WA) - Thursday, Jun 23, 2005 at 15:32

Thursday, Jun 23, 2005 at 15:32
I was also told that this blow back was a sign of stuffed rings... My surf and just about every other 1kz-te I've seen has this same oil around the back of the rocker cover, the car doesn't use any oil between services and I wonder if there is another reason this happens other than the ol' (your engines stuffed mate) answer.
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Follow Up By: ColinD - Thursday, Jun 23, 2005 at 15:53

Thursday, Jun 23, 2005 at 15:53
Hi Jeff, every engine made has blow-by as there is not as yet a perfect way to keep combustion presures on top of the piston. Most comes from the rings gaps, some from the lands (top and bottom) and as the engine ages- the gap grows and the rings become softer due to combustion temp and cold-hot-cold re-tempering. Dont be confused with excessive blow-by, this can only come from too much of the combustion pressure leaking past the rings. This builds up crankcase pressure causing oil leaks that wont stop, and lots of oil being pushed through the PCV system. FACT. You may just have a rocker cover leak.
An engine with too much blow-by may not necessarily use too much oil, the oil control rings may still be doing their job (but unable to stop combustion pressure), also the oil may be topped up by unburnt fuel giving the impression of "no oil consumption". Is your oil thinning before oil changes?
Have a great day.....................col
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FollowupID: 372550

Follow Up By: Member - Jeff M (WA) - Thursday, Jun 23, 2005 at 16:02

Thursday, Jun 23, 2005 at 16:02
Ahhh, I see. No to the conatrary my oil is like vegimite when it comes out. Unsure weather that's good or bad... The way I see it at least the oil is collecting crap out of the engine, but it worries me as to how much is in there somtimes!! I'm just switch the penrite oil on the last change and will see if that make a differnce. I do oil and filter every 5k.

There is not excessive oil around the rocker cover, but it just get's caked on all round there, a big black mess of oiled up dust and sand. It's deffinatally not the rocker cover iteself as it's on top of the rocker covers where the hose goes in. Interesting though, thanks for the explanation... There is no oil in the inlet pipe to the turbo, but I assume if there was a problem the oil would be building up on the other side of the turbo (exaust side)? I havn't had a look at that side, but I did recently look at the intake side as I had to replace the hose.
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FollowupID: 372552

Follow Up By: ColinD - Thursday, Jun 23, 2005 at 16:17

Thursday, Jun 23, 2005 at 16:17
Jeff, only be concerned if there are reasonable amounts of oil entering the inlet tract. Checking for oil after the turbo (pressure side) is a great way to tell the condition of your turbo bearings and seals.
Maybe all you need is a hose clamp over the offending PCV hose.
By the way, PCV stands for Positive Crankcase Ventilation.
Seeya...........................col
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FollowupID: 372557

Follow Up By: Member - Jeff M (WA) - Thursday, Jun 23, 2005 at 16:18

Thursday, Jun 23, 2005 at 16:18
LOL, you're probally right. Thanks very much for the info!
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FollowupID: 372559

Follow Up By: ColinD - Thursday, Jun 23, 2005 at 17:24

Thursday, Jun 23, 2005 at 17:24
Jeff, me again.... 'bout yer oil.
Oil thickening in the smaller high performance diesels is not unusual, some oils are better than others in this respect.
There are factors though that contribute to the condition:
1). Frequent cold running, (short trips, or a thermostat that is too cool or stuck open).
2). Driving hard.
Observe a gentle approach during warm-up (15-20 mins for best combustion efficiency), and make sure the engine is running sufficiently warm during normal operation................col
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Follow Up By: Member - Jeff M (WA) - Thursday, Jun 23, 2005 at 18:29

Thursday, Jun 23, 2005 at 18:29
Oh well, that'll explain it. I have a 10minute warm up button on the dash so you can run the car at high idle for 10minutes without the keys in and it get's that on the cold mornings, but pretty much during the week it's got a 10k round trip to school and back twice a day. Short runs, as you say...

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Follow Up By: JamieMac - Friday, Jun 24, 2005 at 08:40

Friday, Jun 24, 2005 at 08:40
Thanks for the feedback Collin I have mad a combined reply below

JamieMac
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FollowupID: 372645

Reply By: nomad - Thursday, Jun 23, 2005 at 19:12

Thursday, Jun 23, 2005 at 19:12
I made a good catch can for my 84 forrunner diesel (415000 km), like you, I couldn't find anything commercially available that self drained back to the motor, so I made my own.
First you need an old receiver drier off an air con system, then you cut the top off with a hack saw, fill it with stainless steel wool, or scourer pad as the case may be,
then weld the top back on with the tig, or oxy.
I fitted a 16 millimetre pipe into the bottom of mine, and put a 10 mm into the side of the top.
Mount the whole thing up on the fire wall above the engine so the oil has to be dragged up hill.
This is important, so the oil that has defused in the steel wool can gravity feed down.
Because of the diameter of the can, the oil filled air looses villosity, and runs back to the bottom of the can and into the tappet cover.
Had mine in service now for three years no probs, also been using this trick on rally cars for years, because they suffer a similar problem due to high revs.
Hope this helps.
Nomad.
AnswerID: 117112

Reply By: Steve West - Friday, Jun 24, 2005 at 00:15

Friday, Jun 24, 2005 at 00:15
Hi Guys, Where do i start, 1 hz with after market turbo and inter cooler from the day i bought her she used a bit of oil 3 months down the trak on my way to port augusta i got 200 odd kays and low oil lite came on took nearly 2 lt. By the time i got to p/a she'd blown 5lt of oil through the intake. made an oil trap out of a 2 lt cordial bottle breather hose goes in just a little lower than the outlet hose goes out.
on the way home every 150 kay's 1.5 lt oil court in trap. next 2 years or so trying to find cause have now got shares in oil company's repeat company's. previous onwer had new rings put in but d@#k head mechanic didnt hone out bores. possibility 0ne, valve stem seals two,, flap in rocker cover three, there are more but it's late and i carn't think when i'm typing. for the last couple of trips the oil trap has been empty except for a smear of oil which would be common, on saturday i start making my way to birdsville so looking forward to hopefully a good trip but this will be the test to see if i've fixed the problem but it dose seem like i have touch wood. the all mighty turbo was wound up to 12 / 13 psi. And with minimun fordward excelaration on the pedal 10 psi. I wound the waste gate back 10 full turns to achieve 7psi under heavy pedal and 5 psi keeping forward motion.
To much pressure in the bore for the rings to keep up top so pressure slip down into crank case and oil come up and out. i think thats the short version i even ajaxed the poor old girl it worked for a while but didnt last. But i have found the cordial bottle handles the heat pretty good, melt the holes through with a heated up brass fitting the same size as heater hose and yes heater hose dosen't last, by the way outlet hose just drops down behind the axle no fumes while moving if i havent crt any oil by the time i get to p/augusta i'll hook it back up to the air cleaner.
two more sleeps for me and i'll be away for three weeks. Time is to short when it come to holidays. And thanks to Ruth, Karsten and the OZ team for the rd reports I have'nt called Ruthy to cancall accomidation as i'd prefer to do it in person ( the day after when we are leaving )
Regards Steve West
AnswerID: 117165

Follow Up By: rig pig - Friday, Jun 24, 2005 at 02:01

Friday, Jun 24, 2005 at 02:01
Who called the mechanic a d@#k head?

No, who called the d@#k head a mechanic?
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FollowupID: 372631

Reply By: JamieMac - Friday, Jun 24, 2005 at 08:38

Friday, Jun 24, 2005 at 08:38
Thanks all for your input.
I will look at building one myself without too much welding etc if I can help it. Any futher info, pics etc would be appreciated. I do akcnowledge the hints at not load up PCV and dont think this will be a problem with what I intend to do

For info the motor has only 40k on it so I dont think the issue is worn rings. The rings bedding in from new would allow some more blow by I suppose. I also played around with a boost controller and had it peaked at about 15psi at full noise but that was only for a week and it is now removed (fuel pump stayed the same). Regardless that pressure is no where near extreme for a solid motor though I do believe that turbo motors do create more blow by pressure.

The turbo decreases the intake pressure considerably and in combination with the restriction caused by extra piping for the snorkel may drag more flow from the PCV and hence oil with it?

As for legality. I do intend feeding the air after the oil is separated out back into the same position in the intake. I want a closed system where the oil will gravity feed back to the sump or rocker cover and there is no chance of dirt and water ingress.

As for EGR, I think it is the most self defeating piece of junk fitted to this engine. It may be suited to the Euro engines such as the 3.0 litre in the Patrol and Prado but this engine was never designed with it in mind. The net result is that a heap more fuel gets used how can that help the environment. Yes I know its all about certain gases.

Here is my quick environmental balance of risk:
It feeds soot back into the intake = increased wear = earlier engine replacement
Soot is building in the intake = reduced air flow = increased fuel consumption
It robs it of power = more throttle = increased fuel consumption

My GU definately uses more fuel than my GQ ever did and thats enough proof for me!! When I have my way the whole system will be ditched so the motor looks like the pre intercooled model (intercooler will stay though). Nissan have only shoehorned this stuff onto the motor to keep up apearances at a specific engine operating point. In the real world the results are not the positive desired. I'll fold up my soapbox now.

Thanks again for the informative input
JamieMac
AnswerID: 117199

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