20XE breathing heavy

[Iain]

Just replaced my injection setup with carbs. In doing so I've blocked the small rocker breather hole and left the large one going to a catch tank on the bulk head.

It's very visible that it's breathing heavily out of this catch tank filter. When stationary there's smoke coming from the scuttle vents and after a hammering the filter is oily as is the top of the tank and that corner of the engine bay!

The only other change is a Z20LER oil pump.

Never used to be like this. Should I look to put a smaller vacuum back on into the inlet some where?

[Scottcooper85]

Mine runs a pipe on the small vac pipe just loose down the back of the engine. But surely the big one must be doing its job if it's expelling such a volume of gas and oil? What's your oil pressure like mate?

[Iain]

High. About 85psi and doesnt drop much on idle either. But does that increase crank case pressures?

[Will F]

They all breath a bit... And under heavy cornering at high revs you will get oil surge... What it like at idle and static revving?

[Iain]

Smokey from the breather tank filter... Will get a video.

The catch tank has been there for ages and never done this.

If its like this with road use it'll plaster the bay in oil on a track day and they'll probably question smoke coming out the scuttle area...

[Scottcooper85]

Only car I've seen do it before had a breather filter that was blocked with oil inside mate

[Balley]

I have read about this in the past. I believe you need a vacuum from the inlet still just to help loose some pressure. It is certainly worth a try if nothing else.

[Iain]

Might have to have another union welded onto the manifold for that then. Figured it'd just burn most rather than venting. Not ideal as it'd be on 1 cylinder only...

[Scottcooper85]

On nearly all the bodied and carbed engines I've seen though they just block the small breather like you've done and run fine with a catch tank. Just seems weird

[Iain]

Well its just blown up with no compression on #1 and lots of oil in the bore so all in all going well lol

[Scottcooper85]

Well its just blown up with no compression on #1 and lots of oil in the bore so all in all going well lol

One of those weeks then lol

[Benn]

Iirc the small on is the high idel breather... Might be better it being there...

[Will F]

On the plus side, you've found your problem! Lol

[Iain]

Yeah hopefully its just a head gasket and I'll stop pressurising as bad.

[Dar]

Have you done the cam cover modification? It's not your root cause (obviously) but if you take the thing on track you will find that under hard cornering you will pump loads of oil out of the breather without it.

[Iain]

Yep cam cover mod is done, this is breathing heavy on the road.

I think I may have discovered a slight bottom end problem that has contributed lol Pics here pngclub.com/forum/showthread.php?114446-Iain-s-20XE-Trackday-Nova&p=2263450#post2263450

[Dar]

Converted to a link for you.
www.pngclub.com/forum/showthread.php?114446-Iain-s-20XE-Trackday-Nova&p=2263450#post2263450