Oil catch tank question
Discussion
I recently picked up my Fulvia from a well known indie near me and as part of the work an oil catch tank was fitted. Unfortunately I didn't get a chance to discuss the plumbing or location, but I do notice having had a look today that the breather pipe feeds nicely into the tank, but that all the other ports are closed off.
Now, am I being dumb, or is that basically defeating the object of 'breathing'?
Now, am I being dumb, or is that basically defeating the object of 'breathing'?
hermes said:
Now, am I being dumb, or is that basically defeating the object of 'breathing'?
No dumbness at all, you'd get very little breathing with only one output breather pipe. Are there any other breather pipes elsewhere? Engine breathing is critical to ensure no over pressurization. There must always be a filtered air input to the engine, normally via the rocker cover...air/pressure output from rocker cover to the oil catch tank with an additional filter breather output for the catch tank positioned at the highest point of the breather system. It may be there's a return pipe back into the engine, normally fed in near to the timing chain/front cover where the condensed oil vapours can return to engine/sump, negating the need to frequently empty the catch tank. It's also worth asking if the catch tank is baffled, or not? And if not, is there a baffled filter or PCV before the catch tank?hermes said:
I've not had a proper look yet, but it appears that all they've done is re-routed the original breather pipe output from the air filter box straight into the catch tank. It looks like a Mocal tank so I'm assuming it is baffled (like me!)
Not all Mocal tanks are baffled, it's worth checking. If just an output re-route do look for the air input breather otherwise it's restricting output pressure, a proper breather system when not under vacuum needs both filtered input and filtered output with the output being of a larger pipe diameter. Post some pics up so we can take a look. BTW what type/size engine? Well, I'm back from sunny Simferopol and have had a proper look. Basically, as I thought, just a line plumbed from the breather into the catch tank. No baffles in the tank.
Basically a dumb job. Picture attached hopefully, but I think I'll just take it all out and do it properly myself. It's a 1.6 V4 engine.
Basically a dumb job. Picture attached hopefully, but I think I'll just take it all out and do it properly myself. It's a 1.6 V4 engine.
A bit of misconception as to what a catch tank is, I think.
For most post war cars, they are wet sump and an added catch tank does not have to do much - unless the engine fails big style. In this event, although it may be doing lots of miles per hour at first, it doesn't keep on doing them, so no great stress on the new contents.
A catch tank itself is usually quite tall, but does not have a very large section. Think of carrying a glass of water - not too difficult, but then put the same volume of water in a plate and carry that without spilling the contents; not so easy.
Now sold but my 1972 Morgan had one, and like most people with one, I never needed to empty it as there was no volume of oil produced. Perhaps did 30000 miles with it too.
As a contrast, my 1930 Morgan has one, and I empty it quite often via a tap I put in for the purpose. But that engine is total loss lubrication (predecessor of dry sump) and gets through about a gallon of oil every 1000 miles. I could have baffled it, but really no need as the tank is perhaps 3 inches cross section and over a foot tall. Far more important was designing a good condenser to make sure all the oil fell out of the air before venting to atmosphere.
For most post war cars, they are wet sump and an added catch tank does not have to do much - unless the engine fails big style. In this event, although it may be doing lots of miles per hour at first, it doesn't keep on doing them, so no great stress on the new contents.
A catch tank itself is usually quite tall, but does not have a very large section. Think of carrying a glass of water - not too difficult, but then put the same volume of water in a plate and carry that without spilling the contents; not so easy.
Now sold but my 1972 Morgan had one, and like most people with one, I never needed to empty it as there was no volume of oil produced. Perhaps did 30000 miles with it too.
As a contrast, my 1930 Morgan has one, and I empty it quite often via a tap I put in for the purpose. But that engine is total loss lubrication (predecessor of dry sump) and gets through about a gallon of oil every 1000 miles. I could have baffled it, but really no need as the tank is perhaps 3 inches cross section and over a foot tall. Far more important was designing a good condenser to make sure all the oil fell out of the air before venting to atmosphere.
Venting/breathing is indeed the question. The cap isn't vented, so for now I'm just running with it loose. A hole in it is the temporary solution, but I'm still trying to get to the bottom of how a properly plumbed solution works. Most pictures are like the one below, where it all remains a secret!
hermes said:
Venting/breathing is indeed the question. The cap isn't vented, so for now I'm just running with it loose. A hole in it is the temporary solution, but I'm still trying to get to the bottom of how a properly plumbed solution works. Most pictures are like the one below, where it all remains a secret!
take a look here for the basicshttp://oilcatchcan.com/
a proper tank should have 4 ports.
1 from the crank case and
1 from the cam/rocker cover
1 drain back to the sump(although not essential if you would rather empty it periodically)
1 back into the atmo side of the induction system(this should be a cross section area of a minimum twice the above connections to prevent pressurising)
and you should have good baffling inside with adequate volume to allow the oil mist to condense as has been said.
1 from the crank case and
1 from the cam/rocker cover
1 drain back to the sump(although not essential if you would rather empty it periodically)
1 back into the atmo side of the induction system(this should be a cross section area of a minimum twice the above connections to prevent pressurising)
and you should have good baffling inside with adequate volume to allow the oil mist to condense as has been said.
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