Catch tank regs and scrutineer's?

[RobC]

Hi all

Just after a quick bit of advice. I'm moving away from my closed breather system to a catch tank and was wondering what the minimum MSA requirement was. I know about the 1litre minmum capacity but was wondering if it mattered what material the tank has to be made of? (can't see anything in the blue book) I am currently using a 1l hard plastic bottle (old brake fluid container) as a catch tank, it is firmly mounted and does the job very well. In my old bike racing days this would have been fine, but I am not sure what the scrutineer's would make of it? would this be accepted? or do I have to splash out on a ali catch tank?

Thanks in advance for any pointers

Cheers
Rob

[graham bahr]

i've used all sorts of things as catch tanks, the main requirement is that you can easily check to see how much is in them, and how big they are, they need to be 2 litres min for engines upto 2000cc and 3 litre min engines over 2000cc

[Chris Y]

I think the only rules applied really are common sense rules. i.e. Better to use 'rigid' plastics, rather than soft (food use) ones, make sure the oil doesn't corrode the plastic and put a hole through it (seen that done!), and make sure it will hold enough oil for your length of race. Also make sure it's mounted securely.

Couple of years back I used a windscreen washer bottle from a smaller car, mounted on the front inner wing. Sadly at Cadwell Park it got rather full, and then emptied some of its contents on to the front wheel. Oh what a laugh that was as I skated over the grass at the Mountain

Winscreen washer bottles are quite popular, as they're resitant to quite a few oils and solvents, are rigid, and have appropriate mounting points. Some are also quite capacious. Also, if you're not worried about washing your windscreen during the race, or passing an MOT, you can use the one that came with your car

Other things to consider are an easy way to empty it/return the contents to the sump. Some of the more professional tanks have a return line back to the sump fitted with a tap. Make sure you vent the tank in a safe way too - as you want the fumes to escape, but not the oil, so you really need the pipe coming in at the top and well secured, but you also need vents in the top to let the waste gasses out.

[Dom]

I'd second the washer bottle, mine happens to hold 2 litres and is sort of see through, I just have a hose running from my rocker cover in the the top opening in the container with a little clearance around the hose to let the gas out.

I've not yet had a scruitineer complain about it in the last 5 years (but theres always a first time ) Most other folks on a budget in the paddock seem to have similar solutions.

[zefarelly]

I use a pushbike water bottle and cradle screwed to the inner wing, it weighs nothing, is easily removed and emptied, holds a litre, is securely mounted and up to the job and cost only £2.99 . . . . I know it makes sense !

[scrutineer]

I've not yet had a scruitineer complain about it in the last 5 years (but theres always a first time )

I will be looking out for you Dom only joking

[R59]

I'm going through similar thoughts.

I have a dry sump system, and I'm running the rocker cover breathers back to the oil tank, then a breather from the oil tank to a catch tank. Lots of nice shiny aeroquip (and damned expensive fittings!).

The catch tank, which will act as nothing more than a vapour trap, will be be a former washer bottle, which thankfully holds 3L to complement the 6.6L engine.

Another query on the same subject - diameter/bore of the pipework - what would you consider a minumum? I'm using -12AN for most of it.

Rob.

[coln72]

Good question. My old man used tubing which was too small and blew the dip stick out of his motor...............

[graham bahr]

Originally Posted by zefarelly

I use a pushbike water bottle and cradle screwed to the inner wing, it weighs nothing, is easily removed and emptied, holds a litre, is securely mounted and up to the job and cost only £2.99 . . . . I know it makes sense !

good idea but you know the blue book says it needs to hold 2 litres???

[Chris Y]

Dunno what size mine is. I just call it the "F'in Large Pipe"

The problem with my engine (and similar ones) is that they breathe quite heavily, even when freshly rebuilt. One of the breathers is quite low down in the sump, so gets a lot of oil thrown at it.

So, I have a complicated 'expansion tank' idea, just above the oil filler pipe (which leads to the gearbox side of the sump). This enables the oil to shoot up under heavy load, and hopefully return to the sump in 'quieter' moments There's a pipe at the top of that leading to the catch tank. The expansion tank is another washer bottle - from a Furred Fester I think.

[Richy_Rich]

Hm, interesting. My current engine breathes back into the carbs (as the original car did), previous engines I've had set up breathing into catch tanks etc.

This wasn't really a concious choice, but it came back from the engine builders like that and gave more power than the previous one on the rollers, so I've left it.

Is there a compelling reason why I should change back to breathing into a catch tank?

[StephenRae]

Originally Posted by Richy_Rich

Hm, interesting. My current engine breathes back into the carbs (as the original car did), previous engines I've had set up breathing into catch tanks etc.

Is there a compelling reason why I should change back to breathing into a catch tank?

This is likely to mess your mixture up...if any crancase compression builds up you are going to lay down a sizeable smoke screen

[listernoble]

For hill climb and sprint cars I think the min size is 1 litre
Lister

[Richy_Rich]

Originally Posted by StephenRae

This is likely to mess your mixture up...if any crancase compression builds up you are going to lay down a sizeable smoke screen

Good point, it's not a hassle to switch back so I may well do that.

[zefarelly]

Originally Posted by graham bahr

good idea but you know the blue book says it needs to hold 2 litres???

thats the same size as the sump !!!

my engine doesnt breath anything much anyway the only time the catch tank filled up is when I put a rod through the block and the coolant displaced the oil

[RobC]

Thanks for all the replys.

You had me worried for a second regarding sizes, but it looks like the racing vs hill climb/spring regs are different and I only need 1ltr for sprinting. Looks like the only issue I have is that you can't see the level, unless you count removing the hose to see if its showing on there. Hummm...what to do...might have to go the bike bottle route (nice and cheap, spent enough on the dam car this spring!)

[Anuauto]

Never had problem with just looking in the top after pulling hose out of an opaque tank. As you have independently established after a lot of well meaning but conflicting information, min capacity for speed events is different from racing. Some racing orientated scrutineers have had to be reminded at speed events that the regs are different. Sometimes wonder why they turn up when vehicle eligibility in speed events never seems to be challenged and so many react adversely to the simplest of queries aimed at merely establishing a level playing field!

[RobC]

Valid point, I might make up a "dip stick" for it can't argue with that...can they As it is the engine doesn't blow anything out (odd for a K I know)

[zefarelly]

I've found on the Kent engines (pre or crossflow) the breathing is entirely down to where you put the breather . . .sometimes it pours out sometimes its virtually nothing other than a bit of vapour and steam if its been sitting for a few weeks

[Peter Mallett]

Originally Posted by StephenRae

This is likely to mess your mixture up...if any crancase compression builds up you are going to lay down a sizeable smoke screen

Not only that. It weakens the mixture and you can suffer pinking and at racing revs that will burn a valve.

First thing to do with those systems is to put in a catch tank and block the oil breather into the carb.

[graham bahr]

zef

you must have a very small sump then, most hold 4-5 litres of oil

[Tim Falce]

Originally Posted by graham bahr

zef

you must have a very small sump then, most hold 4-5 litres of oil

That would be a luxury, I need at least 10 to 12 litres to keep the oil pressure up when I rev the engine.

[graham bahr]

well yours is a little on the large side............

[RobC]

Originally Posted by falcemob

That would be a luxury, I need at least 10 to 12 litres to keep the oil pressure up when I rev the engine.

10-12 litres...sure your not mistaking your engine for a central heating boiler

[graham bahr]

Originally Posted by falcemob

That would be a luxury, I need at least 10 to 12 litres to keep the oil pressure up when I rev the engine.

with all that oil sloshing about your corner weights must go a mile out round the bendy bits