Oil catch can - AAN

[hunker7]

Does anyone have a diagram for oil catch can for stock AAN engine, or is it possible to add catch can to original system?

There is quite a lot of oil on lower boost pipes and would like to reduce that if possible.

[Tractor Dave]

There is no catch can on the original system. Oil fumes are passed back into the intake system when not on boost. The control valve for this may have failed. Easy to change and not expensive.
It's also quite easy to add a catch can and delete all the existing breather system. If you search the forum there are some good how to threads.

[hunker7]

There is no catch can on the original system. Oil fumes are passed back into the intake system when not on boost. The control valve for this may have failed. Easy to change and not expensive.
It's also quite easy to add a catch can and delete all the existing breather system. If you search the forum there are some good how to threads.

No I know there isn't a catch can originally fitted, but don't know if adding one would reduce oil build-up. Both of the valves seem to operate correctly.

I've searched old threads but unfortunately a lot of pictures have been lost due to photobucket

[Tractor Dave]

Ok, just adding a catch can to the existing pipework won't really help much. If you are adding one you might as well go full monty. I did one for another Forum member a couple of years ago on an aby engine and it was quite straightforward.

[hunker7]

Do I have the right idea? Inlet 1 & 2 going to catch can, and outlet feeding back into turbo hose?

[newsh]

Yes basically, cam cover and crankcase to can then can back to MAF hose (via tube through cad cover.
You can leave the larger black valve in place and go from there to the can. It restricts the vacuum to the engine at wot.

Also you can leave the small valve at the inlet manifold connected if you want, as it only opens on overrun when the throttle is shut to purge fumes from the breather system and CC.

[hunker7]

Small valve, can I just use a T piece to feed back into Inlet 1?

[hunker7]

After digging through threads and threads of discussions this is the setup I've decided to go with as it keeps N80 system intact, although I have 2 questions;

1. Majority of cans come with 1 inlet & 1 outlet, I imagine I could use a T-piece to run crank & cam vents together?

2. Would a 300-400ml can be enough, assuming only downside would be how often it is emptied?

[89 Coupe]

Here is some good inspiration, it should answer all of your questions
https://www.youtube.com/watch?v=j6zYaB5DBJI

[hunker7]

Here is some good inspiration, it should answer all of your questions
https://www.youtube.com/watch?v=j6zYaB5DBJI

Very informative

I'll probably go for something like this and take it from there, mine is only standard and wouldn't be tracked.

[newsh]

After digging through threads and threads of discussions this is the setup I've decided to go with as it keeps N80 system intact, although I have 2 questions;

1. Majority of cans come with 1 inlet & 1 outlet, I imagine I could use a T-piece to run crank & cam vents together?

2. Would a 300-400ml can be enough, assuming only downside would be how often it is emptied?

It's probably better anyway to T the cam cover pipe into the crank case pipe low down then come up to the catch can, then if you accelerate hard and get a bunch of oil running out the back of the cam cover most of it will drain back to the sump, rather than filling up the catch can. Using a large diameter pipe from the CC up to the van will slow the speed of flow and encourage oil to drop out on the way up.

[hunker7]

It's probably better anyway to T the cam cover pipe into the crank case pipe low down then come up to the catch can, then if you accelerate hard and get a bunch of oil running out the back of the cam cover most of it will drain back to the sump, rather than filling up the catch can. Using a large diameter pipe from the CC up to the van will slow the speed of flow and encourage oil to drop out on the way up.

Looked at it today and due to large crankcase vent I might just modify original metal cross pipe which will allow me to use single inlet and then route back to cam cover. Can't see myself going back to original setup anyways. For N80 I'll just replace original t-piece with 90 degree silicone hose.

[Mr G]

Following this thread.....please post pics of your install and maybe a write up (for a noob ) of what you did - TIA

[K Simmonds]

If fitting a catch can I would always avoid a return to the sump. Yes it does require more frequent emptying but you really don't want what's in the can back in the sump, it'll be mostly water anyway as well as some grotty oil.

3-400ml would be about perfect and require emptying every 5K miles, mine was about 500ml but it didn't need to be that big. I did mine about every 2K miles as I wanted to keep an eye on what was finding it's way in there and always found very little other than a bit of really crappy oil/water emulsion.

The above is assuming a standard car up to 400+ BHP, if your running some crazy power level then you may find you do need extra capacity.

[hunker7]

If fitting a catch can I would always avoid a return to the sump. Yes it does require more frequent emptying but you really don't want what's in the can back in the sump, it'll be mostly water anyway as well as some grotty oil.

3-400ml would be about perfect and require emptying every 5K miles, mine was about 500ml but it didn't need to be that big. I did mine about every 2K miles as I wanted to keep an eye on what was finding it's way in there and always found very little other than a bit of really crappy oil/water emulsion.

The above is assuming a standard car up to 400+ BHP, if your running some crazy power level then you may find you do need extra capacity.

Sump return seems to be very dividing opinion, but unless you have so much power it fills up with straight oil, return to sump makes no sense.

Mine is only 260hp so will do just fine and probably won't need emptying too often.

Current plan is to weld AN10 fitting on top of original crossover pipe for inlet to catch can to make disconnecting easier.