oil catch can non return valve

snaken · #1 (**permalink**) 08-27-2009, 12:09 PM

Has anyone fitted a one way valve in the return line back to the sump from the catch can.
I think my braided line and fittings are dash 6

Got any suggestions

Snaken

Philm · #2 (**permalink**) 08-27-2009, 07:06 PM

HI Snaken,
A question why do you have a return back to the sump?

I assumed an oil catch can is there for when the engine is in trouble and pumps the oil into the rockers. I will have to check but I think Cams require a can the same capacity as your engine, eg a 5lter requires a 5lter catch can.

In my engine I have a 7 ltr can and after a few months get a small amount of condensed vapour in the can that I drain and that is it.

Phil

snaken · #3 (**permalink**) 08-28-2009, 04:02 AM

Hi Phil, for some reason my Ford Motorsport 347 with the individual throttle bodies is a heavy breather, like I am a heavy drinker, and the catch can has vapour constantly breathing so I thought perhaps the pressure is coming up from the sump rather than from the rocker covers

Aussie Mike · #4 (**permalink**) 08-28-2009, 09:36 PM

I've got a 1 way check valve in a return line to the sump. There's an AN#6 fitting welded on the bottom of the catch tank. Earl's make a 1 way check valve with AN#6 connections on each side. This is installed in line. There's a return welded low down on the front cover. This keeps it above the oil level and from the crank's oil windage.

Mando · #5 (**permalink**) 08-29-2009, 03:13 AM

Snaken, do you run any air filters on your trumpets? If so could you post a pic for me please. As far as the non return valve from the catch can, I've got the same setup as Philm with a gate valve flush with the bottom of the chassis that can be turned on and off to drain the oil from the catch can. I would have preferred to return the line to the sump but had no provision on the sump. I hope it meets regs when the time comes for rego inspection.

Regards.

snaken · #6 (**permalink**) 08-30-2009, 05:27 AM

Mando,

Will try to attach air cleaner photos. If it does not work, PM me and I will send to you.

Snaken

Mando · #7 (**permalink**) 08-30-2009, 06:08 AM

Snaken, did you make your filters or did you buy them? Could you post some pics of your distributor for me, Im interested to see what you used with your cross over manifold.

Regards.

Leeroy · #8 (**permalink**) 08-30-2009, 05:05 PM

Snaken

I did what you are considering last year. I was alway getting at least 1/2 litre of oil in catch can after 15 minutes or so on the track (road use none)

I ran a AN6 line from bottom of c/can and welded a tee into the base of the dip
stick tube with one way valve. It works great without ever needing to drain c/can again. Check mine out next Sat. if you like as very easy to do.

Leeroy

Mando · #9 (**permalink**) 08-30-2009, 06:42 PM

Hi Leeroy, are you saying the 1/2 litre of oil is coming from the rocker covers? I was planning on running a hose from one of the rocker covers to the catch can and sealing the other rocker cover. Is this OK or should it be vented? Does anyone know what is needed by the rego people?

Regards.

snaken · #10 (**permalink**) 08-31-2009, 05:16 AM

Hi Mando,

I made the filters, stainless sheet drilled to size of trumpet openings, bent up the edges and welded s/s mesh in a semi circle. Glued on special foam rummer used on air compressor filters and other industrial uses.

The dissy drive is a standard Ford item, off Explorer I think used to connect with coil drivers and coil packs.
As you do not have a PCV valve you will need to vent both rocker covers to the catch can. As leeroy experienced mine is fine on the road but at high revs at the trak there is considerable pressure and associated oil. You need to run large (dash 1o 12) hoses to the catch can.

Cheers
Snaken

Aussie Mike · #11 (**permalink**) 08-31-2009, 07:28 AM

That's pretty much the same setup as I built. I've got 2x #12 lines coming off the valley cover rather than the rocker covers. There's less oil mist in there. Easy to do on a Gen3 as there's no distributor in the way. The tank is baffled and has an oil separator setup inside it. It's fairly large volume and would hold 3L or more I would guess. I don't get much oil mist through the filter but after that last track day at Winton it collected a liter or more of oil. That's why I've plumbed the return line now.

Cheers

Mando · #12 (**permalink**) 08-31-2009, 08:10 PM

Snaken, I wasn't as clear as I should have been. I've got a PCV valve on one rocker cover that's connected to the top half of the catch can. The top of the tank has a vacuum line connected to my vacuum block. At the base of the tank I have a drain line that runs to a small gate valve at the bottom of the chassis.
Does the other rocker cover need to be sealed or vented?

Regards.

snaken · #13 (**permalink**) 09-01-2009, 05:12 AM

Hi Mando,

I really dont know I am a professional bean counter. I would think you probably need both vented if you are going to avoid build up of crank case pressure. Interested in seeing a photo of your vacuum block.
Here is a better shot of the dissy area of my motor

Snaken

Mando · #14 (**permalink**) 09-01-2009, 07:59 AM

Snaken, this is my vacuum block.

Regards.

Aussie Mike · #15 (**permalink**) 09-01-2009, 08:33 AM

Mando,

I'd seal the other valve cover or run a line from each cover. The PCV valve is a 1 way check valve that's designed to promote a vacuum in your crank case. At part throttle when manifold vacuum is high it pulls from the crank case also creating negative pressure in there. When you put your boot down your manifold vacuum drops off but the PCV check valve closes keeping the crank case vacuum up.

All engines have a certain amount of blow-by where combustion pressure leaks down past the rings and into the crank case. It can also sneak out through the valve guides. The main reason for the PCV is it stops the crank case pressurizing and forcing oil out through your crank seals and other places. Crank case vacuum also promotes ring seal as the rings are pushed out against the cylinder wall by the combustion pressure. Crank case pressure works against this pressure.

It's been popular in drag racing to use a mechanical engine driven vacuum pump to generate high levels of crank case vacuum. The power used to drive the pump is more than made up by the extra power made by good ring seal.

Mine is just vented to atmosphere that creates the need for large diameter lines for max airflow. There's a school of thought that says burning that oil vapor actually drops the octane rating of your fuel. It may not be legal for rego but I rould rather catch and condense the oil vapor and return it to the motor than burn it.

Cheers

Gav · #16 (**permalink**) 09-01-2009, 09:34 PM

Oh Mike, how would you know how it works?
You won't even come to the Nationals to drive it!

I have tried positive encouragment, now trying negative..

Aussie Mike · #17 (**permalink**) 09-01-2009, 10:19 PM

Meanie!

I've forgotten what it looks like. 3 trips to Thailand and 1 to NZ in the last 2 months. Another trip to Thailand and one to the Philippines in the next month or so. I probably should just pay someone to paint it.

Cheers

sambo · #18 (**permalink**) 09-01-2009, 10:22 PM

Mike, look at it this way - at least the filler has plenty of time to cure.

Gav · #19 (**permalink**) 09-01-2009, 10:25 PM

That wouldn't be quite as fun though.

dadndave · #20 (**permalink**) 09-03-2009, 12:30 AM

I run a pcv off left bank through catch can then back to base of carburettor ( Road Demon) and I Run a line from the other rocker cover into the base of the aircleaner. Stopped all oil weeping problems instantly. Only thing I forgot was to put a baffle plate under the opening with the pcv. Filled the catch can with 1 litre in 20 minutes. could have been interesting when the catch can filled completely and pujre oil sucked directly into manifold