Oil Catch Tank

[Matt brown]

Im finding that the rocker cover has more fumes coming out which is why I got the tank, thought I could just run crack and rocker into one but doesn't look that simple from what others have said so looks like I'm going to run rocker into the catch then just vent the crack like it was before

[tractor]

Ooo venting the crack

Edited March 9, 2017 by tractor

[Guest mower man]

Im finding that the rocker cover has more fumes coming out which is why I got the tank, thought I could just run crack and rocker into one but doesn't look that simple from what others have said so looks like I'm going to run rocker into the catch then just vent the crack like it was before

Pm your home snail mail address and i'll post you some pics mick [free]

[Jez Morton]

Have you removed the one way valve from the crank breather, this will allow pressure to build in the block which leaves through path of least resistance the filler cap breather. I had this problem on my last car which had twin webbers it sprayed oil out all over top of engine. Pull crank breather pipe out of the engine and there should be a metal piece at the end with a hole in the bottom, cut the bottom off it and a plunger and spring should come out. I did this and just added a filter to the top of the pipe and no more issues.

I think the one way valve is to stop fuel getting in the block as its normally connected to inlet manifold, when the engine is running the vacumn in the inlet draws the fumes out and they get burnt in the engine.

 

Jez

[Matt brown]

Not sure as was already vented when i got the car, when up to temp you can see vapour coming out of the crack breather if that helps

[Jez Morton]

Sounds like the valve is out, if vapours coming out. On mine I only got a light mist around the oil cap that could be wiped off now and again but that was the old style cap without a vent pipe. You could try connecting the vents to the air filter through the back plate that may give enough draw to remove the fumes.

[Matt brown]

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Just went to check and that looks like some sort of valve to me if you could clarify that would be great

[Longboarder]

The breather consists of a holder/canister pushed into the block firmly. Like a little tin can on a stalk. This has a chunky rubber insert in the top. Into this the breather valve assembly is inserted and joined to the pipe by a black plastic elbow. The pipe, elbow and valve can be pulled upwards and out of the rubber insert. If you now look at the end of the valve you will see a central disc which is sprung closed but can easily be pushed open. Held by an internal spring you cant see and the lip of the valve. You just grind the lip off and the valve disc and spring drop out. Couldn't find a before picture but I have an after mod pic below.

 

Nigel

[Matt brown]

That's probably the most informative explanation of somthing I have ever had thanks, I'll have a look tomorrow

[Snapperpaul]

Excellent explanation from Longboarder as always

Can I just add a bit of related information, the pressure buildup and related airflow though an engine is a little contradictory.

Pressure in the crankcase is aided by ring blow by however on a standard engine the filler cap is vented and the crank breather sucks crank gasses out using manifold negative pressure.

There is a situation when the crankcase breather is pulling pressure out of the crank case and the filler cap is sucking clean into the engine to equalise because the crank case and the rocker cover are connected by the oil drains from the head to the block.

When you remove the vacuum savaging from the breather system only positive pressure has an effect, in a sense your only blowing out.

Some breather solutions run a pipe from the crank case to the side of the rocker cover and a separate outlet from the rear of the rocker cover to the catch tank freeing up one feed of the tank for a vent.

A lot of high performance Pintos run this system.

 

Proper catch tanks have baffles and wire wool to separate oil from air and vent the air.

 

I had a catch tank that had 2 inlets and no filtered vent so I put a Y connected into one of the feeds and attached the filter to it the result was that pressure built in the tank as both inlets were tacking pressure and oil spewed out of the filter.

 

I'm sorry this is a long winded post so here are my conclusions.

 

You can effectively run a crank and rocker vent feed to a vented, baffled catch tank with wire wool in the top section

Or

You can run the crank case breather to the side of the rocker cover and run a second breather to a non vented catch tank and put a small filter on the spare feed.

[fry61]

Out of interest -- how much oil is caught in the catch tank say per 1000 miles? The 1800 CVH engine in Florin is piped crank to rocker cover & rocker cover to back of remote air filter ( in the nose ) I wonder if this is where Florins smoking habit comes from.

[Snapperpaul]

The first bit is good, but no catch tank? well you can't catch the oil in the vented gas

The other issue is the filter is lower than the rocker so fluid will just flow out.

Have a look at the Burton catalog as it has a good diagram on Pinto catch tanks.

[Matt brown]

So it turns out the crack valve was still there

 

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So modified it and re fitted, the engine seems to run alot smoother and alot less vapour coming from the filler and more from the crank.