oil catch cans

[Darren]

I've often read about the oil drainage problem the Holden V8 experiences at higher rpm and after the recent QR track day, it's become apparent to me that my engine suffers from it when pulling 6000+rpm out on the track.

So I'm looking at the idea of fitting up an oil catch can - the legal way of course ie venting back to the engine. I haven't had a lot to do with these things so was wondering if anyone with some experience in this area has any tips before I purchase one. On a Holden V8, do you run both rocker covers into the catch can or just the left side (keeping in mind the right bank draws in fresh air, whilst the left bank pulls out crankcase fumes via the PCV). And I assume you retain the PCV valve ?

And any recommended brands ? I'm not into 'bling' factor, mainly functionality.
One of our sponsors Hiro has one here http://hiroperformance.com.au/hiroperformance/products/GReddy-Oil-Catch-Tank.html Do you reckon it would do the job ?

[Carbon]

I have the ASE Turbo one Darren. It is purpose built for the VE's and VZ/Vy's but I'm sure you custom fit it.

[Darren]

this one Adam ?
http://www.aseturbo.com/skins/Sandbox/php/getImg.php?src=/images/uploads/thumbs/thumb_VE-catch-can.jpg&width=178&height=130

those ones vent to the atmosphere - defect material :p
I've edited the link to the one Hiro has on their site. That's the one I was thinking of - it vents back to the engine
http://hiroperformance.com.au/hiroperformance/product_images/q/greddy_oil_catch_tanks__70311.jpg

[Carbon]

mine kind of looks like that......

[Darren]

mine kind of looks like that......

lol, I didn't see it :hit head:

[John]

I would just run the one side into the catch can. You can leave the other side without issue as the pressure will just alleviate itself through the sump and back up the other side along the oil return paths.

I run my oil return line from the turbo into the drivers side rocker cover for 2 years without a issue (Same as if you plugged your drivers side). No leaks or oil overflow problems.

[ghz28]

Darren, I know Dan the guy I go racing with has had issues as you describe, with his VK, but they are now resolved. I will find out from him what his system is like. I believe the real problem is like the skylines, the oil gets trapped up in the heads so you need an alternative drain back to the sump.

Will let you know what I find, but I do know he has two things, an oil/air separator near the radiator, and then the catch can plumbed off that. He revs to 6700 odd all the time and no issues now.

Garry

ps you could always dry sump it and the scavenge pumps will get rid of your problem once and for all.....lol The skyline guys I know run scavenge lines up to the head there is so much up there when they rev hard.

[Darren]

well Gary I might just try the catch can idea first, before dry sump - might solve my rear main oil seal leak though lol :p

as you mention I suspect it's the oil pooling up in the heads/rocker covers. If I was aware of this common problem at the time I built the engine, I would have had the oil drain in the heads enlarged (apparently a fairly common mod these days).

wasn't burning oil out on the track, but after parking it in the pits between stints, I'd start the engine for the next round and it would create a smokescreen out the exhaust for about the first 10 seconds or so, and then clear up again. And hasn't occured again since the QR day. So obviously the sustained higher rpm was the culprit

[DC347]

I have an ELITE 1 that was a group buy on the ls1 forum. Saw the other day the thread has come back up maybe another group buy on the way. The ELITE one looks good and is very functional

[pvk308]

Hey Darren mate yes you will need to run both covers to the can or other wise you still you get windage and frothing of the oil. You can still run the pcv valve but run it off of one of the rocker covers that works best mate. Any oil that does go into the catch can can be returned to the sump through a drain that drains back through the fuel pump plate on the side of the timing cover..... these are only minor mods and wont make a big difference, to get the most out of the oiling system your going to have pull the engine down and do mods to the oiling system inside the motor

[MonaroMick76]

I ran a HQ headed 308 in my Monaro up until I took it off the road 5 years ago to do some modifications to the driveline and never got it going again due to lack of funds.

I constantly used to have problems with it pushing oil out through the rocker covers gaskets onto the headers. I never fully solved the problem as I didnt get a chance to install my ultimate oil catch can.

The main problem with pretty much any 308 is that they pump too much oil up to the cylinder heads at high rpm especially if they have a high volume oil pump. They really dont need a high volume oil pump you just need to restrict oil flow to the heads using edge-orifice lifters or the like, and in turn that will help oil flow to the critical areas like mains and conrod bearings.

I would suggest that most of what the guys are saying above is correct, especially the comment made about dry sump systems, unfortunately they are probably too expensive for most people to run though and you need a good gasket seal otherwise it will suck the gaskets in with too much suction from the pump.

The best design of catch can is something that you dont have to empty all the time so has a drain back system back into the sump, separates the oil fumes from the oil, condenses the oil and can be collected and only allows the minimum amount of oil vapours to be sucked back into the engine.

Oil vapour fumes can actually reduce the knock point of the air/fuel mix entering the engine and can bring on engine destroying knock earlier if the oil vapours are too strong. I would recommend having a catch can that breathes fresh air through the engine filter via some sort of one way valve, so the oil vapours cant be sucked or pushed back into the motor under load. And definitely take the oil fumes off both rocker covers as this will ensure both sides of the engine work in a similar fashion.

To help with separating the oil inside the catch can a labyrinth style system can be used to take the oil on an elaborate path to make the oil stick to the walls and condense with other oil and for the vapours to return to the engine. Stainless steel mesh is also good used inside a catch can as it helps
to separate the oil and vapour better.

I hope I havent confused anyone with my suggestions and that it may help you out.

[Darren]

yes that was very helpful Mick, Steve (and everyone else) cheers.

Been doing a bit of reading up in my VN V8 factory manual, it explains the way the PCV works on the 5L. L/H bank is connected to a vacuum port, drawing fumes from the engine via the PCV valve (there is supposed to be an oil/air seperator built into the elbow coming out of the l/h rocker cover). The R/H bank draws in fresh air from the throttle body (no vacuum).

So for starters, I was thinking of trying (to keep it simple), is to hook the catch can up to the l/h rocker cover (basically fit it between the pcv and the existing vacuum hose coming from the engine). That way, the catch can is still using vacuum to draw out the fumes/oil, and the engine is still breathing fresh air from the r/h rocker cover (connected to the throttle body). Next track day I'll see how it goes, if the problem still exists, I'll look at hooking both covers up.

Ideally I'd plumb the drain of the catch tank back to the engine (as Steve suggested) however the later EFI engines don't have a fuel pump hole/plate in the timing cover, it's moulded over & I don't want to drill & tap a thread into anything or bits of metal are going to end up inside the engine. The track day at QR was the first and only time I've experienced the problem. Usually the engine doesn't use oil, so I'm figuring the only time it's going to fill a catch can, is on a track day. I can handle emptying it after a day out on the track. I don't forsee it trapping large quantities of oil for normal street driving, because the engine doesn't normally use oil.

I can't really afford to regularly hit the track, more than likely I will only get the car out on the track a few times a year. So yeah, not looking at spending a fortune with dry sumps, pulling the engine apart etc. A bandaid solution in this case is fine ;)

[pvk308]

Darren mate i would install the set up in the car with out a pcv and plumb the set up for track days ie rocker covers to catch can (should give you an extra 200rpm on idle as the engine will be breathing freely) like that, then for the drive home make sure the its set up as per factory its functional and will comply with adr when on the road (I know your thinking that already mate). There isnt much you can do apart from an engine rebuild except as you said drain the catch can after each short run etc i would hate to see you starve a mains bearing or rods

[Darren]

I should be right for oil reserve Steve, got a high capacity sump which takes about 7L to fill
I lost maybe 1/2 a litre on the track day, that's 150km of track work

[pvk308]

Thats not a bad ratio at all im assuming the sump is baffled etc which would have helped keep us posted mate and good luck

[Darren]

thanks for the advice Steve, will let you know how I go

[pvk308]

no worries mate and good luck with the old girl