ALFAGTV6.COM

Vince · Post by **Vince** » Sun May 29, 2005 11:14 pm

I have recently discovered that there is quite a lot of oil in the intake accordion hose and which is burnt in the engine, giving off some smoke in the tailpipe. The smoking stopped after plugging the hose(to the oil trap at the cam cover).

It seems like there is too much vacuum in the crankcase, sucking out some of the engine oil/fumes. I only noticed a hose from the accordion hose to the oil trap that provides for vacuum. Is there a vent for the crankcase where fresh air is drawn in...ala the positive crankcase ventilation setup? I suspect this vent is clogged creating the the high vacuum in the crankcase. Or maybe there is a PCV valve that is faulty?

Appreciate if anyone can advise if there is a PCV valve installed on
the GTV6? How does the crankcase provides for ventilation? Thanks in advance!

Vince

David · Post by **David** » Sun May 29, 2005 11:36 pm

Vince,

There isn't an air intake in the crankcase. I put an oil catch can on my GTV6 but I must admit I don't think it helped that much.

I would be careful about plugging that hose. I originally restricted the flow through the catch can and 2 tappet cover gaskets gave way over a few months after a couple of sessions of hard driving and high revs. I can only put that down to too much pressure in the crankcase. After refitting hoses close to the original size, I haven't had the problem again.

Could be a coincidence but others may have some thoughts on this.

David

Jim K · Post by **Jim K** » Mon May 30, 2005 12:06 am

The link hose between the O/V separator and the throttle intake pipe is the only connection from the crankase to the 'outside' world. If you plug that up and all engine gaskets are tight, you may see the dipstick jump out, especially in a worn engine! Technically, when the motor is idling, pulling the dipstick out should increase the revs, as supplemental air is induced. A sealed crankcase is a prerequisite for proper emission control anyway, all vapors being directed to the intake and burned(?). The only way to keep your engine clean, is to route the vapor hose into an air-vented catch tank, just like all racers have to do. If you want to experiment with gaining some additional power (1-3% as they say), you can dump the vapor hose in the exhaust pipe at an angle (so there's a constant suction) and the crankcase will operate in a a 'vacuum', minimizing windage losses! There, i've said my bit for the day, laugh all you want!

Jim K.

Vince · Post by **Vince** » Mon May 30, 2005 12:33 am

Thanks for the opinions...

Dave: Sorry, I could have been clearer....nope, I plugged the hose to the intake accordion hose. The outlet(to the accordion hose) from the oil separator is left open to the atmosphere. Maybe a separate oil catch tank is the solution. But so far, there hasnt been any smoking!

Jim: U are a genius with those great ideas! But I am quite baffled with the excessive oil being sucked into the engine. Is the oil separator ineffective; it doesnt seem to be serviceable?

Vince

Jim K · Post by **Jim K** » Mon May 30, 2005 12:45 am

Personally, I think the very simple V6 separator is too small in size, not giving enough time for the vapors to cool and allow suspended oil drainback, a fact made worse by the hole in the aluninum fitting going to the intake beeing too large.
Jim K.

Seb · Post by **Seb** » Mon May 30, 2005 1:00 am

My problem after the 3.0QV conversion is that I have no runback. The dizzy is mounted there now... Guess I´ll just place a small container hidden somewhere.

Seb

David · Post by **David** » Mon May 30, 2005 2:18 am

Jim,

I agree, that separator will never do a thing at high revs which begs the question, were these engines always designed to burn some oil this way?.
I've only ever noticed black smoke at full power and I seem to recall reading somewhere the L-jet goes into 15% enrichment at full throttle over a certain revs.

David

Mats · Post by **Mats** » Mon May 30, 2005 3:00 am

Have you tried to carfully clean the oil separator?
That is a common problem here up north, they freeze in the winter and then the car starts to smoke like crazy. Clogging would give the same symptom.

Maurizio · Post by **Maurizio** » Mon May 30, 2005 3:31 am

If you want to experiment with gaining some additional power (1-3% as they say), you can dump the vapor hose in the exhaust pipe at an angle (so there's a constant suction) and the crankcase will operate in a a 'vacuum', minimizing windage losses!

Guess what I am brewing lately, I’m still looking for a good one way valve, like this one http://www.rockauto.com/ref/SMP/SMPDeta ... l?AV11.jpg .

Seems ok, only the fun part is shipping to Europe for $75,- and part is ~ $17

Greg Gordon · Post by **Greg Gordon** » Mon May 30, 2005 7:46 am

The problem is the stock Alfa air/oil separator sucks. Check out the first picture on this page www.oldebottles.com/italiancarspage5.htm . We are using that separator on our cars. With the hose pointed up and the transition to a smaller hose on the uphill side zero oil gets into the intake, just fumes.

This separator is a common parts store item, ie NAPA, Vato Zone, etc.

Mats · Post by **Mats** » Mon May 30, 2005 12:01 pm

omg, Greg. I think there is a Neon octopussy trying to mate with your engine...

Maurizio: Why not the one-way to the brake booster? You are getting rid of the booster anyway, arn't you?

Greg Gordon · Post by **Greg Gordon** » Mon May 30, 2005 3:31 pm

You think that's neon. You should see the all Yellow set up on my daughter's car!

Vince · Post by **Vince** » Mon May 30, 2005 4:26 pm

Found this Sard oil collector tank, wonder if it works? Anyone have one of this under their hood....

Vince

Maurizio · Post by **Maurizio** » Mon May 30, 2005 11:17 pm

Mats wrote:Maurizio: Why not the one-way to the brake booster?

Yep, thought of that one too, have several one-way valves laying around for testing. But the problem is finding a hose (exhaust to valve) which can stand the heat. The valve I posted is somehow designed to isolate the heat.

You are getting rid of the booster anyway, arn't you?

I have not decided to throw it off, yet. (Still drive the car on the public road also, home to ring and vv). Haven't driven a car whithout booster.

Greg Gordon · Post by **Greg Gordon** » Tue May 31, 2005 6:07 am

You can't connect the air/oil separator to the exhaust. The smog police will shoot on site if they find that.

Crankcase Ventilation Valve (PCV)