Oil Catch Tank...

[Longfield 0]

Today I thought it'd put my plumbing back in on my 205. When it was built, in addition to an oil cooler an oil catch tank was installed. But, I can't see how it would actually get any oil in it and thus am curious to understand if it's really worth having it or not. The reason why I can't understand how it's ever get any oil in it and thus 'catch' the oil is because the feeder pipe into the catch tank is right at the top of the plastic bit that you actually use to put the oil into the engine. So I honestly can't see how oil would get from the sump and vertically [against gravity] try to escape the engine. I never had this problem when my 205 was a road car so I can't see how it'd be a problem now it's a competition car.

 

Could someone please enlighten me? I've attached a photo to try to help in my explanation.

 

thanks

Longfield

[MerlinGTI 3]

its carried in the vapour and gases, not a lot but its there. Ever looked in the bottom bit of the standard inlet mani for an 8v? theres usually a couple of tablespoons worth in the bottom. Your probably never fill it up, but its nice to know your engine is munching away on clean air rather than the TB / intake mani etc.. getting gummed up with mankey oil contaminated stuff.

[steve@cornwall 100]

Is it a closed container or does it allow venting somehow? If closed and sealed I would have thought it would have helped to over pressurise the crankcase?. Just having a kink in the standard pipe (cap to inlet hose) made mine spit oil from the dipstick when revved high. I'd have thought it more effective to "feed" the tank direct from the crank breather hose by the sump and return / vent it back to the inlet.

[Longfield 0]

Is it a closed container or does it allow venting somehow? If closed and sealed I would have thought it would have helped to over pressurise the crankcase?. Just having a kink in the standard pipe (cap to inlet hose) made mine spit oil from the dipstick when revved high. I'd have thought it more effective to "feed" the tank direct from the crank breather hose by the sump and return / vent it back to the inlet.

 

It's interesting reading your reply as the first time I took it on track we thought we had an oil leak. It turned out oil was getting chucked out the dip stick which had never happened before. Also the pressure is very high, even though the catch tank has a vent in its lid.

 

When you said feed the tank from the crank breather hose by the sump and return / vent it to the inlet my questions here are:

1 - is the feed on the oil catch tank the top or the bottom hose?

2 - am I right in thinking the 'inlet' is the top hose on the plastic bit where you put the oil in the engine?

 

Thanks

Longfield

[steve@cornwall 100]

It's interesting reading your reply as the first time I took it on track we thought we had an oil leak. It turned out oil was getting chucked out the dip stick which had never happened before. Also the pressure is very high, even though the catch tank has a vent in its lid.

 

When you said feed the tank from the crank breather hose by the sump and return / vent it to the inlet my questions here are:

1 - is the feed on the oil catch tank the top or the bottom hose?

2 - am I right in thinking the 'inlet' is the top hose on the plastic bit where you put the oil in the engine?

 

Thanks

Longfield

 

When you look at the breather/filler hose on the bottom of the block, I would expect the small breather hose that splits off from the main flller pipe to go to the catch tank. If there are more than one pipes on the tank (maybe 1 at the top and 1 2/3 of the way down?) I would use the lower one for the "feed" pipe.

 

Return would be to the inlet manifold ("sucking" against the crank pressure)

 

This would give the required closed system for road use. If it's a track car I guess you could just take the cap off the tank and vent to the air

 

I must stress this is only my theory based on what I am thinking of for mine to aid crank ventilation and hopefully cut down on "mayo" blocking the breather tubes as my car is not used too often.

[Longfield 0]

When you look at the breather/filler hose on the bottom of the block, I would expect the small breather hose that splits off from the main flller pipe to go to the catch tank. If there are more than one pipes on the tank (maybe 1 at the top and 1 2/3 of the way down?) I would use the lower one for the "feed" pipe.

 

Return would be to the inlet manifold ("sucking" against the crank pressure)

 

This would give the required closed system for road use. If it's a track car I guess you could just take the cap off the tank and vent to the air

 

I must stress this is only my theory based on what I am thinking of for mine to aid crank ventilation and hopefully cut down on "mayo" blocking the breather tubes as my car is not used too often.

 

Given your theory... is mine set up ok? I have two pipes comming off my block and one off my sump. A large one that the filler pipe goes on and a second smaller pipe. Off the large one that goes to the filler pipe, there is as you suggest a smaller hose that splits off it. This smaller hose feeds its way into the rocker cover and not, as per your theory into the catch tank. The second pipe comming off my block is of medium size and returns to the filler pipe which you can see as the shiny black [kinked] pipe just below the filler cap. The pipe that comes off the sump is for approx a 10mm hose that goes into the lower part of the oil catch tank with the hose from the upper part of the oil catch tank also going to the top of the filler hose. So I have a total of 2 return hoses going to the top of the filler hose. Does this make sense?

[Longfield 0]

Reading again what you have written, I think what you have suggested as a potential 'return' is the breather for my brake servo as the pipe from from servo goes into my inlet manifold.

[steve@cornwall 100]

Finally managed to sneak a look under the bonnet! You are correct about the smaller breather pipe that comes off the filler going to the rocker cover - I had this confused. It's the other breatherpipe from the bottom of the engine block (that goes to the back of the filler tower) that I woyuld expect to run to the catch tank.

 

Without a vent for the tank , the crank case pressure would just build - If you run a return to the tower, you're just putting the pressure straight back! Where you have taken the tank feed from at the minute usually goes to the large intake pipe between AFM and Throttle body - you don't have this anymore (carbs, yes?) If you run a closed filter box, you could vent to that ( oil droplets should be gone, just pressure would return to be eaten by the engine). If not , duplicate of the union that the servo pipe comes off could be used.

 

I would most probably run with the catch tank cap off, if you have a MOT tester who requires a closed system for the test ( My tester would not test for emissions on the 1.1 without all pipes in place, which was a shame as emissions plummeted with the breather pipes off) run a return pipe to the tower for the test only and replace the cap!

[wardy18 33 1 Cars]

i have exactly the same tank on mine but i also use it for oil filling too

 

mine has 2 smaller inlets at the top and one larger outlet at the bottom and is plumbed as follows:

 

Crank Breather to 1 smaller inlet

 

Rocker cover breather to other smaller inlet

 

Oulet going straight down to sump filler pipe

 

Im a bit confused on how it "catches" oil as surely its more of a recyling tank (just like the standard oil tower breather unit) cause any oil to come in the 2 inlets at the top will then run down to the bottom of the catch tank and surely out of the outlet directly back into the sump