viriiguy

iTrader: (1)

Hey gang,

On my SC'd Miata I currently have no PCV system and both sides of my valve cover are just vented to atmosphere. The obvious problem with this is I lose ALOT of oil.

Should I build some type of catch can to capture the oil and then pour it back into the motor every day or two? Or what should I do?

I figure you Turbo guys have touched on this once or twice

Thanks

sixshooter

iTrader: (12)

Use a 323 GTX pcv valve is often plumbed from the valve cover and connected to the intake manifold and yes, a catch can on the other opening. But I would hesitate returning the oil to the engine as it is often laced with condensation moisture upon exiting the valve cover. But even homemade catch cans are quite effective.

m2cupcar

iTrader: (5)

If you're not running ALOT of boost, then you shouldn't be losing ALOT of oil.

musanovic

iTrader: (2)

catch can + http://www.summitracing.com/parts/SUM-120108/

fooger03

iTrader: (2)

do it like mazdaspeed does? run a return line from the bottom of the catch can, through a check valve, and into the oil pan.

I'm running a JAZ 1-Pint mini breather tank (get it in natural plastic instead of black if you want to see a 'fill level')
http://www.jazproducts.com/breather_tanks.html
I imagine you could make it work while you're planning on replacing your piston rings.

ARTech

iTrader: (34)

I agree. Sounds like excessive blow by. Maybe you need a rebuild.

thagr81 us

iTrader: (5)

Agreed with m2 and AR... If you are losing enough oil to where you would have to pour the oil from the catch can back in every day or two, there are other problems. Get a compression and leak-down test done on that engine.

viriiguy

iTrader: (1)

I am running 16lbs of boost and I loose about 1 quart for every 400 miles. Or so it seems. I had a compression and leak down test done prior to buying the car and all looked ok. I will look into doing it again. I will also grab a catch can this weekend if I get a chance and run the system into that. At least that way the oil isn't blowing all over my engine bay or garage floor.

thagr81 us

iTrader: (5)

1 quart every 400 miles!? O.o Something is definitely up with that... I had a blown oil pan gasket and didn't even lose that much.

viriiguy

iTrader: (1)

It is an estimation... But I figure it to be fairly close. I will monitor it a bit closer the next couple weeks. The car does not see a lot of road time atm. So I MAY be looking at rings, but I sure hope not. The motor only has 20k miles on it. I would think that Weisco pistons and rings would last longer than that. The oil is definitely coming from the drivers side of the valve cover where it is just vented to atmosphere.

I had not really been paying a lot of attention to it until I changed the oil last week.

m2cupcar

iTrader: (5)

If you're venting to atmos, and you're losing 1 quart every 400 miles, then you have one of two situations: 1) you have an engine bay covered with oil 2) you don't have an engine bay covered with oil because the oil is being burnt and sent out the exhaust.

saint_foo

Or someone is siphoning it while you sleep!

There's really the only 2 places it should be going. One thing you can do is get a huge piece of cardboard and continue to park on top of it. If you notice oil dropping there, great, get underneath the car and try to trace it up to a source.

When you floor it, is there a huge cloud of blue smoke behind you?

gospeed81

iTrader: (51)

When mine was losing a quart every 400 miles (my exact number) it was parked within 2 weeks, and had a new motor within a month.

Cococarbine3

iTrader: (1)

+1. In my case it was 3 seized oil control rings, which I suspect is the main problem with mysteriously disappearing oil in many miatas.

miatamike

Gary at Trackdog Racing had a similar problem. He took two catch cans welded them together made a bafel between them and now it doesn't have any oil in it. Its the weirdest thing, before that he couldn't even go a full session at MSR without it over flowing his old catch can. You should call him and ask him about it.

viriiguy

iTrader: (1)

miatamike, I will probably give him a call.

After reading thru this.. maybe my estimation is a bit off. I get it based off of the fact I changed my oil, run the car for 15 minutes, then checked my levels and topped off. Then after a 400 mile drive I had to add another quart.

I KNOW the only place the oil is getting out from is where I have vented to atmosphere. To prove this I removed the small air filter I had there and put a rubber hose. All the oil I find comes from that hose.

Maybe I am WAAAY off on my oil loss. Like I said I will keep a closer eye on it now. It could be possible that I had an air bubble in my oil lines that caused me to be a full quart low. I did after all have most of my oil lines off for engine clean up and re routing.

But regardless, I need to get a catch can, install it and monitor just how much oil really is going in there.

m2cupcar

iTrader: (5)

Put that hose in a beer/soda can and you'll find out just how much oil you're losing from the vent. Put both the vent port and the pcv port (cap the mani port) to that can and you'll find your total loss from crankcase pressure.

viriiguy

iTrader: (1)

That is a good idea. I do not have a intake manifold port and I have a custom Intake Manifold.. hence the no PCV system. But I can easily run the hose to a soda can when I get her back out this weekend.

Thanks!

Why the heck didn't I think of that.......

mazpr

iTrader: (1)

On a 1.8 dohc engine, maybe an ounce every 3 to 4 months.