340BHP-WRX

iTrader: (6)

I've asked this question before but never really put my mind at rest so need some more advice !

I have removed the catch tank system that I previously had fitted and have the 2 rocker breathers and the crankcase breather all vented to atmosphere with some hose. I have also removed the PCV valve and blocked off the hose that goes to the manifold.

Once the car is warmed up im getting alot of smoke from the 3 breather hoses,alot of it is condensation and there is no oil coming out at all.

What's bothering me the most is when i'm sitting at traffic lights theres so much smoke coming from under the car that it looks like its burning oil-like when oil gets on the manifold. If I unscrew the oil filler cap or remove the dipstick there is smoke puffing from there aswell.

Has anyone else had the same as this ? If you have your breathers vented to atmosphere,do you get the same ?

My engine is relatively new so I hope its nothing serious !

Any ideas ?

340BHP-WRX

iTrader: (6)

Anyone ?

Slowboy Racing

From what you have said it suggests excess crank case compression being caused by blow by from the cylinders. I would have a compression test done to confirm this As it’s a sign of a tired motor.

.

340BHP-WRX

iTrader: (6)

That's what I was worried about but it's a fairly new engine-rebuilt by Api last year for the previous owner,approx 11,000 miles since rebuild !

Alan Jeffery

Have you tried it with the breathers connected up properly?

340BHP-WRX

iTrader: (6)

No I haven't. Would that make a difference ?

silent running

Well it couldn't do any harm seeing as that's how it was supposed to be in the first place. Just off the top of my head, having the two rocker breathers connected to your crankcase breather is just going to basically recirculate oil vapour round and round in a circuit, seeing as the rockers are supposed to be drawing in clean air, not the filthy air out of your crankcase. But they won't even be doing that because you have no vacuum pulling it out.

IMHO it would be surprising if a system with all breathers teed in together DID work properly, although I accept that a few people seem to have theirs working. I can't see how though.

340BHP-WRX

iTrader: (6)

None of my breathers are teed together-I have 3 hoses all vented to atmosphere.

The original setup could cause harm due to the oil vapour being fed into the engine reducing the octane of the fuel and causing det apparently.

rossi_classicwrx

hopefully this isn't the case with yours but thats the exact symptoms my car had when it melted a piston. It did what yours is doing at first then pretty soon after the engine was a write off. do a compression test and that will tell you straight away. Mine was the number 3 piston. i think the rings were screwed first then the whole lot went. Mine was caused by a very poor setup from a well known tuning company which made my car run too lean.
Hopefully theres another reason that can cause this but it does sound exactly like what mine had and it caused a very large repair bill for a new engine!

Slowboy Racing

I wouldn’t plumb the breathers back in, it could actually make it run worse if its breathing as heave as described.

Compression test will answer your questions; you can get a tester kit from Halfords for around 15. Bring the car up to temp disconnect the cam sensor so you have no fuel when cranking, remove one plug and connect the tester to that cylinder. Then you crank the motor over until you see the gauge go no higher take note of the reading reconnect the plug and move on to the other three cylinders the same way.

Your looking near even figures on all cylinders ideally when warm.

silent running

Yes sorry my mistake. You've got them all vented out. You still don't have any vacuum of any kind on the crankcase to pull out the gases because you've blocked off the PCV side and have vented what's left to atmosphere.

Oil vapour drawn through the PCV valve cannot cause detonation - it doesn't work when there's any kind of boost available.

You may have an ongoing problem with cylinder leakage in which case you need a compression test, or it may be that you've been running without the vacuum side of your breathers connected that the oil vapour has accumulated to huge levels and it's finally 'spilling out'.

Compression test is probably a good first thing to do though. If this comes up OK, then reconnect your PCV valve for starters. That will clear your crankcase of fumes straight away.

340BHP-WRX

iTrader: (6)

What compression readings should I get ? The car had a health check before I bought it and has a receipt for a compression test-all 4 cylinders were around 170-180psi.

If it is a serious problem as has been suggested would it not burn oil and run poorly ? Mine has no blue smoke from the exhaust and runs fine ?

340BHP-WRX

iTrader: (6)

The main reason for venting all 3 pipes as i've done is on high boost im running 1.4 bar and all of the tuners I spoke to said it's best to have the fumes venting to atmosphere or a catch tank which isn't plumbed back into the system as oil vapour will cause det !

340BHP-WRX

iTrader: (6)

Another thought-when I had my catch tank plumbed in and the PCV valve still connected I had the same smoke from the oil filler and dipstick and I had a pipe venting the catch tank to atmosphere and that had smoke coming from it aswell ?

jasonius

iTrader: (1)

So are you saying all the oily vapours/residue sitting in the intake-IC-TB won't lower the octain rating (potentially causing det)..?

Slowboy Racing

It’s really hard to no what one person sees as a lot of smoke or vapor to the next when not being able to see the car ruining. If you had a compression test done with the results 170-180psi I would say that’s very good, so you would be looking for the same or near results The most important being they are even..

mr_D

iTrader: (12)

im bringing this thread back to life, sorry about this. my friend has just started having this and i noticed i get a little but next to nothing compared to him. my smoke comes out of my catch can. but his comes out of his oil filler and crank case more than anything.

now i did a compression test on my car the other day and i got
9.3
9.5
9.5
9.7
(in bar)
bearing in mind my car is 13yrs old. and i know should be between 10 - 11 i think that was 1,3,2,4 or something like that.

did anyone ever find out what this cause was. i have a suspected lean issue and my friend thinks he has just done a piston due to running really rich.

340BHP-WRX

iTrader: (6)

Unfortunately it was my engine that was knackered !

I've since learned that excessive smoke/compression gasses coming from the oil filler/crankcase breather is a sure sign of engine problems. In my case it was a cracked piston ring land

DDS789

iTrader: (2)

Gutted dude

Had the same on mine in 3 pistons!! Would squirt oil out the dipstick lol

Running in my forged 2.1 now though

mr_D

iTrader: (12)

really?

see now i notice some little smoke every now and then but my mates just bellows it out

Baz82

I'm having the same problem maybe time to take th engine out

The Stitcher

iTrader: (12)

are you running big enough pipes to your catch can mr d ? eg 15mm pipe or bigger and also the outlet of the catch can the same ?