Jump to content
SAU Community

Recommended Posts

Got a frustrating prob with my car at the moment.

It is breathing a significant amount of oil from the breather. If I nail it all the way through 2nd, 3rd and 4th ( RB20 - 225rwkw ) it will spew out approx. 5 tablespoons worth of oil.

Now before I am told the rings etc are gone and I need a rebuild etc a compression and a leak down test were carried out with the results not pointing to a stuffed cylinder instantly.

Compression was on average 150 with no other cylinder more than 5 away and the worst leakage was on cylinder 6 with 19%.

The mechanic told me that 19% isnt the best but should in no way let that much oil get out.

Is it possible that a cylinder with 19% leakage can let that much oil get through and indeed a do need a rebuild?

Or could it be something else?

I have been given two other possibilities as to the cause ( not from mechanics ):

The gauze that is meant to be under the breather hole has been removed at some time causing an excessive amount of oil to get in or the oil drainage from the rockers has partially blocked over time meaning the oil is getting up there fine but it cant drain back fast enough and its getting sucked up through the breather?

Any help on this matter would be much appreciated.

Thanks

Link to comment
https://www.sau.com.au/forums/topic/64529-heavy-breather/
Share on other sites

My friend had the same problem, his breather was like a kettle blowing, even went to the extent of making it harded for air to get out to his catch can by altering his cam covers, piston number six was stuffed. He never did a compression test though. you got to remember that with the compression test nothing is firing, so you have 19% difference. imagine how much gas get's blown by when the piston fires and then when your nailing it on boost! gas travels from the sump area blowing all oil up with it. if it was a serious wrecked valve stem seal you should see allot more smoke on start up.

Link to comment
https://www.sau.com.au/forums/topic/64529-heavy-breather/#findComment-1208628
Share on other sites

No,not 19% difference.

Besides having the compression test done I also had a leak down test performed and the worst leakage was 19%. Not a 19% difference between cylinders on the comp test. The biggest difference between cylinders on the comp test was about 3%.

Link to comment
https://www.sau.com.au/forums/topic/64529-heavy-breather/#findComment-1209045
Share on other sites

Are you using more fuel? If you are it could be your oxygen sensor gone which puts more fuel in as it thinks the engine is running lean this then washes the oil off the bore which gives you blow by as theres no sealing effect from the oil

Link to comment
https://www.sau.com.au/forums/topic/64529-heavy-breather/#findComment-1209093
Share on other sites

Interesting Ben101. At present my fuel economy is ridiculous. Approx. 18L/100km on CRUISE!

I have recently had an ecu fitted up and obviously it needs to go back as not much attention was paid to cruising mixtures.

I would be a happy chappy indeed if all the problem was is a rich tune, but honestly I had never heard of rich mixtures causing excessive blowby but it sounds feasible.

Link to comment
https://www.sau.com.au/forums/topic/64529-heavy-breather/#findComment-1209886
Share on other sites

The biggest difference between cylinders on the comp test was about 3%.

Hmmm, got my little mechanical mind stumped then. The only reason I can think of oil blowing out your breather is your getting allot of gas in your motor which would come from the piston. Has anyone ever had a valve stem seal let exhaust gas through blowing a heap of air into the cam journal? You should have smoke on statrt up then. Don't know my friend!

Link to comment
https://www.sau.com.au/forums/topic/64529-heavy-breather/#findComment-1210624
Share on other sites

To tell if its worn rings smoke will appear through out the driving range and idle if its valve stem seals you will only blow smoke under vacuum eg giving the car some but you have good compersion it sounds like the fuel economy is way to rich the ecu needs to be re tuned to much fuel going in can wash the bores down which then washes the oil away and will wreck your hone pattern on the bores which will lead to more problems down the road

Link to comment
https://www.sau.com.au/forums/topic/64529-heavy-breather/#findComment-1211242
Share on other sites

  • 2 weeks later...

It seems as though the problem is solved so I thought I would post this up to help out anybody in the future.

On advice from another forum member (from NSW I think :) ) I checked the pcv for the prob as I was told if it was not shutting properley it could blow boosted air into the head.

I removed the hose to it and took the car out for a spirited drive to come back to find not a single drop of oil had breathed out.

I repeated this test several times and same outcome everytime, no oil at all.

So once again, SAU forums has saved me some money and I learnt something at the same time.

Thumbs up!

Link to comment
https://www.sau.com.au/forums/topic/64529-heavy-breather/#findComment-1230815
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Yeah, all the crude is used for fuels and petrochem feedstocks (pesticides, many other chemicals, etc etc). But increasingly over the last few decades, much of the petrochem synthessis has started with methane because NG has been cheaper than oil, cleaner and easier and more consistent to work with, etc etc etc. So it's really had to say what the fraction either way is. Suffice to say - the direct fuels fraction is not insigificant. Heavy transport uses excruciatingly large amounts. Diesel is wasted in jet heaters in North American garages and workshops, thrown down drill holes in quarries, pissed all over the wall to provide electricity to certain outback communities, etc etc. Obviously road transport, and our pet project, recreational consumption camouflaged as road transport, is a smaller fraction of the total liquid HC consumption again. If you're talking aboust Aussie cars' contribution to the absolute total CO2 production of the country, then of course our share of the cubic mile of coal that is used for power generation, metallurgy, etc adds up to a big chunk. Then there is the consumption of timber. Did you know that the production of silicon metal, for example, is done in Australia by using hardwood? And f**king lots and lots and lots of hardwood at that. Until recently, it was f**king jarrah! There are many such sneaky contributors to CO2 production in industry and farming. NG is used in massive quantities in Australia, for power gen, for running huge water pumps (like, 1-2MW sized caterpillar V16 engines running flat out pumping water) for places like mine sites and minerals/metals refineries. And there are just a huge number of those sort of things going on quietly in the background. So NG use is a big fraction of total CO2 production here. I mean, shit, I personally design burners that are used in furnaces here in Oz that use multiple MW of gas all day every day. The largest such that I've done (not here in Oz) was rated to 150MW. One. Single. Gas burner. In a cement clinker kiln. There are thousands of such things out there in the world. There are double digits of them just here in Oz. (OK< just barely double digits now that a lot of them have shut - and they are all <100MW). But it's all the same to me. People in the car world (like this forum's users) would like to think that you only have to create an industrial capability to replace the fuel that they will be using in 10 years time, and imagine that everyone else will be driving EVs. And while the latter part of that is largely true, the liquid HC fuel industry as a whole is so much more massive than the bit used for cars, that there will be no commercial pressure to produce "renewable" "synthetic" fuels just for cars, when 100x that much would still be being burnt straight from the well. You have to replace it all, or you're not doing what is required. And then you get back to my massive numbers. People don't handle massive numbers at all well. Once you get past about 7 or 8 zeros, it becomes meaningless for most people.
    • @GTSBoy out of the cubic mile of crude oil we burn each year, I wonder how much of that is actually used for providing petrol and diesel.   From memory the figure for cars in Australia, is that they only add up to about 2 to 3% of our CO2 production. Which means something else here is burning a shit tonne of stuff to make CO2, and we're not really straight up burning oil everywhere, so our CO2 production is coming from elsewhere too.   Also we should totally just run thermal energy from deep in the ground. That way we can start to cool the inside of the planet and reverse global warming (PS, this last paragraph is a total piss take)
    • As somebody who works in the energy sector and lives in a subzero climate, i'm convinced EV's will never be the bulk of our transport.  EV battery and vehicle companies over here have been going bankrupt on a weekly basis the last year. 
    • With all the rust on those R32s, how can it even support all the extra weight requirements. Probably end up handling as well as a 1990s Ford Falcon Taxi.
    • Yes...but look at the numbers. There is a tiny tiny fraction of the number of Joules available, compared to what is used/needed. Just because things are "possible" doesn't make them meaningful.
×
×
  • Create New...