ProVent Modification - Lowering backpressure

[Longranger1]

I did a little test recently and found that the ProVent 200 can be a little restrictive which is not a good thing for turbo compressor oil seals. These seals are often only a labrynth or piston ring type which do not like any rise in crankcase pressure above atmospheric. This is one reason why the turbo oil drain back to the sump is usually a good size.

A rise in crankcase pressure can force oil out through the turbo compressor seal which is exactly the opposite of the purpose of having a catch can device installed. Mann-Hummel acknowledge this by fitting a relief valve to the filter cap which supposedly should eliminate pressurisation problems. I beg to differ...

The material used in the filter once oil soaked, is too restrictive.

Here is my solution.

http://s1125.photobucket.com/albums/l58 ... =010-1.jpg

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http://s1125.photobucket.com/albums/l58 ... =009-1.jpg

I used synthetic flyscreen material wrapped around the original filter core after removing the original fine 'fabric'.

The inside was filled with stainless pot scrubber which is "de rigeur" for home made catch cans.

The result? A lot less restriction with no discernable loss of oil mist catching ability .

[Kegsy]

Never even considered there would be a problem with back-pressure with the provent!

I was happy before I read this Pete

[Longranger1]

Never even considered there would be a problem with back-pressure with the provent!

I was happy before I read this Pete

Geez Mate I am sorry! But my findings shocked me too .

I've set a cat amongst the pidgeons now...

[Kegsy]

Never even considered there would be a problem with back-pressure with the provent!

I was happy before I read this Pete

Geez Mate I am sorry! But my findings shocked me too .

I've set a cat amongst the pidgeons now...

Ignorance is bliss

No big deal, looks like an easy fix. Top marks for the skeptic within

[Longranger1]

Ignorance is bliss alright, this caught me by surprise after finding oil in the intake. The return hose from the ProVent to the intake pipe was spotless with no oil inside at all. It was as dry as the day I fitted the ProVent.

It doesn't take too much of a rise in crankcase pressure to cause issues though.

[Cowboy Dave]

I tried to edit your post to bring the images into the thread but it wouldn't work. I've got the links from Photobucket instead - makes it easier for tapatalk people etc. Hope that's okay (and that it works).

[Cowboy Dave]

I've been thinking about my provent of late. The drain hose leaks. I tightened the little hose clips as much as I could and it still leaks. So I ordered the proper drain hose from western filters to replace the crap one I put on but I haven't fitted it yet. Meanwhile I tied it to the chassis in an out of the way spot that was less likely to drip and now I have a well oiled piece of chassis near the passenger front wheel that drips a bit of sump oil sometimes. The other problem I have (one of many in truth... ) is squeaky rear springs. I was thinking on the weekend (as only a dodgy DIY'er could ) that perhaps I should just put a really long drain hose on the provent and run it all the way back along the chassis rail to where my squeaks are on the springs. That way the leaking oil will keep the squeaks lubricated and I won't have to worry as much about either of them. Not sure of the impact on pressure of a long hose though...

What would be interesting to watch though is whether my leaking drain hose is being pressurised and that is why I am getting my leaks, and if so how much pressure is there.

[coxy47]

Nice work Pete. Im keen to see how this goes in the long run. Judging from this i assumed you traced the leaking oil to the turbo then?

I was thinking on the weekend (as only a dodgy DIY'er could ) that perhaps I should just put a really long drain hose on the provent and run it all the way back along the chassis rail to where my squeaks are on the springs. That way the leaking oil will keep the squeaks lubricated and I won't have to worry as much about either of them. Not sure of the impact on pressure of a long hose though...

The length of hose should have no impact on the back pressure in the system. My only concern would be the oil getting to places you dont want and attracting too much dirt.

What would be interesting to watch though is whether my leaking drain hose is being pressurised and that is why I am getting my leaks, and if so how much pressure is there.

The easiest way to test if the pressure is causing the leaking is just to remove the filter temporarily and see how it goes.

[ag9111]

I've been thinking about my provent of late. The drain hose leaks. I tightened the little hose clips as much as I could and it still leaks. So I ordered the proper drain hose from western filters to replace the crap one I put on but I haven't fitted it yet. Meanwhile I tied it to the chassis in an out of the way spot that was less likely to drip and now I have a well oiled piece of chassis near the passenger front wheel that drips a bit of sump oil sometimes. The other problem I have (one of many in truth... ) is squeaky rear springs. I was thinking on the weekend (as only a dodgy DIY'er could ) that perhaps I should just put a really long drain hose on the provent and run it all the way back along the chassis rail to where my squeaks are on the springs. That way the leaking oil will keep the squeaks lubricated and I won't have to worry as much about either of them. Not sure of the impact on pressure of a long hose though...

What would be interesting to watch though is whether my leaking drain hose is being pressurised and that is why I am getting my leaks, and if so how much pressure is there.

Nice lateral thinking Dave , unfortunatly rubber bushes and oil dont mix

[Cowboy Dave]

Maybe I'll find something bushes do like and then see if my engine will run with it... I've been meaning to get under there with a hammer for some attitude adjustment but everything is covered in dirt and dried mud so it didn't seem like a fun thing to do. Maybe Brendan or Fraz will take pity on me and do it for me. Or I could wash the truck I guess. See, lateral thinking all the time here...

[ag9111]

Urethane bushes

Arent you a mod, why are we so far of track

[Cowboy Dave]

I learned from the best.

[daryn]

Dave never goes off track, just pulls others up for doing so, don't we Dave......

[Tony]

This is why I dont particularly like these things. yea, is good to remove some (only some) oil mist from the intake but they do tend to add positive pressure in the sump with no question. I have seen oil weeps appear, seals pop out, dip sticks pop out and spray oil etc ,then.... as LR pointed out, if the positive pressure backs up the turbo oil return in effect you will have some oil pass the seals. Not usually a big issue but does sort of defeat the purpose.
As the engine gets more blow by with age the problem increases significantly.

Some of the fit ups I've seen on this site (not picking on any) are way to restrictive in the plumbing side. We dont want long runs of reduced diameter hose nor small elbows etc. This sort of thing will cause more restriction due to friction than the actual core material. Combination of the two are pretty tough on things.

I'm trying to avoid using these things on my fleet if possible. So far my MN hasn't needed it. Dont seem to get much oil mist in the intake to speak of. I do wash the I/C out at least once a year though.

Not over filling the crankcase with oil (So doesn't foam)does help in some cases too.

[Homer]

Beetroot tin guys...beetroot tin. I told ya's years back

Or in Tony's case a Jam tin...then it might start to sound sweeeet like the V6

[Longranger1]

Quick update on this. This definitely breathes a lot better than the the original ProVent filter media.

For the sceptics, just undo the hose off the rocker cover and give it blow like a lung function test (Alan Gray style of mechanical diagnosis ). This will show just how restrictive these things are .

The flyscreen mod works really well with little restriction and good oil mist catching ability.

As Tony said, it defeats the purpose of the catch can if it forces oil out of the turbo compressor seal. If that happens then the thing is pretty much useless.

[Pauly_t]

I thought the provent filters had a feature that negated this type of thing, I quote "Integrated safety feature
against irregularly high crankcase pressure". This is from their flyer thingy. Is this not what your talking about.

Not a expert by any stretch of the imagination.

Paul

[Longranger1]

It does indeed have a pressure relief valve, but IMHO it cracks at too high a pressure to stop oil being forced through the turbo seals. It doesn't take a lot of crankcase pressure to cause oil leaks.

Not an expert either, just learned this from my observations.

Just try blowing through a ProVent with an oil-soaked filter .

[Sky Miner]

Ahhh.....why not just buy a new filter if a oil soaked filter is causing this drama wouldnt this negate the overpressure prob.....i would have thought

[Mooons]

Are the filters reusable or throw away jobs

[Longranger1]

Throw away I think. Not cheap either.

[mattz]

Throw away jobs.
They are not cheap to replace either.
$60 or $80 rings a bell.

[mattz]

Great minds think alike.

[Sky Miner]

Throwaway jobbies......but you are spouse to get ...about 50k out of em ' thats not bad really

[Longranger1]

Flyscreen is cheap though .