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I have some questions about Oil catch cans

14K views 8 replies 6 participants last post by  NooNoo  
#1 ·
Are they damaging to the engine or are all pros and no cons?

Whats up with these two diffrent connecting setup?

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Why do people connect it up diffrent?
 
#2 ·
No cons that I can think of - the difference between the two setup is that one is venting directly to atmosphere. Personally I wouldn't do it that way as it apparently stinks!
 
#3 ·
No cons that I can think of - the difference between the two setup is that one is venting directly to atmosphere. Personally I wouldn't do it that way as it apparently stinks!
The venting directly to atmosphere is the second one or the first picture i posted?

And im thinking of buying an oil catch can kit of ebay. is that okay or? http://www.ebay.com/itm/Racing-Engine-Oil-Catch-Tank-Can-Reservoir-Hose-Set-For-VW-GOLF-LUPO-POLO-GTI-/401054992162?hash=item5d60bd8722:g:IegAAOSwT~9WlxVU&vxp=mtr
 
#5 ·
Cons include a huge increase in crankcase pressure with those vent to atmosphere set-ups as the small diameter pipe coupled with that tiny little filter which saturates with oil vapour hugely reduce gas flow.

That diameter pipework is used when it is syphoned via the inlet, you need something less restrictive when venting to atmosphere.

The second picture will work and will catch a lot of oily water condensate, but does not stop hot, low-oxygen vapours returning to the intake
 
#6 ·
As above; venting to atmosphere is bad for the block because it can't breathe and when W_O_T there's no way of the vapour being drawn out of the crankcase - whereas if it was vented back to the inlet it would.

People that VTA are people that either don't care, don't understand or don't know what they're doing IMO. Out the rocker/crank, through a can and then back to inlet is the only way!
 
#7 ·
If the VTA setup is not restrictive then it will breath fine without the need for it to be drawn out..... But crucially it has to be a large enough bore. A single 19mm pipe is no good. and one with a stupid little filter on the end simply won't cut it

The benefits of a VTA setup means you don't have that hot, oil rich vapour going back in to the intake replacing the cool, dense oxygen rich air you would otherwise be drawing in through the intake/filter.

On a high compression oil burner I would certainly go with image 2 above.
 
#9 · (Edited by Moderator)
Cars vented to atmosphere for years before emissions came about.

At W-O-T blow by gases on turbo charged engines ensure positive pressure in the crank area so venting isn't an issue.

The issue is at idle if the PCV system has been removed. The crank does stagnate with gases in this case.

The gases simply aren't sucked out by the near vac behind the throttle body.

:Y: