Rear Head Drain/breather

[kev_31t]

my 30/25 has a rear oil drain fitted, as i have seen heaps of people say these are useless whats the best thing to do with it?? cheers

[XKLABA]

It's more a crank case breather then a drain either way if it isn't a problem leave it there

[Ben C34]

Read the oil control thread to get an understanding.

[kev_31t]

at the moment it is plumbed into the turbo drain, i wasnt to keen on that idea as it runs real close to the manifold

[GTRPSI]

Whoever did that assumed it was to be used as a oil drain then.

These days its been established that its a breather, usually run to the top of the sump, above oil level on the drivers side.

[XKLABA]

Sump is to low, it needs to come of the block

[kev_31t]

Sump is to low, it needs to come of the block

so is it ok to T into the turbo drain? as the 30 block only has one drain where the 25 block has the vct drain bung aswell

[GTRPSI]

Sump is to low, it needs to come of the block

Up near the block flange is fine on the sump, no oil there, minimal if your turning sharp left and for some reason your under a lot of boost at the same time.

Only hole ideal for a block breather is on the hot side, but im not a fan of running escaping gasses up the pipe that the turbo oil is trying to drain down from.

Also wouldn't try boring a dirty big hole and tapping a thread on the cold side, too chicken to go that radical.

[XKLABA]

That's what I did, drilled and tapped a an -16 in the block webbing on the hot side and run it to the back of the head and two an -12s on the intake side going to the cam covers, car has made 623hp at all 4 so far with no issues so far, RB30 block

I have found over the years if you track your car, which I do, and you over fill the oil to the bump in the stick which you should if you track your car then turning hard left under boost does happen, as PIGGAZ experienced at SMSP last year when his catch can over flowed making a big mess in his engine bay

James, yes but it's best to run it to an open area ie the Nismo catch can, to slow the flow of air/oil to give it somewhere it can seperate before joining the head and use as big of a hose as possible to reduce the air/oil velocity through volume

[GTRPSI]

In your case, tracking the car, do you have a larger capacity deeper sump with trap doors?

If so did you feel it still needed the extra oil to cover for pooling in the head with extra breathing mods done?

Just interested in your angle of approach.....i like hearing of things from a different angle, might pickup something i didn't know or think of.

There is always more than i way to skin a cat.

[XKLABA]

Yeah, 9.5ltr performance metalcraft sump and with the platinum sump adaptor it puts it around 10 ltrs, plus overfilling to the bump

Yeah, I always fill to the bump, the more oil you can get in the sump the better without overfilling it to the put it hydraulics and the bump seems to be the norm nowadays, there are many reasons to have extra oil in the engine, oil pooling in the head is just one

When you understand the why of why oil "pools" in the head then it is actually fair easy to rectify and I have done what I think is enough to stop this happening, on top of what I have mentioned I also have a an -12 line as a drain from the bung between the exhaust manifolds and all the internal drains have been drilled out to 10mm and the rear drains opened up to the gasket holes, so oil getting traped in the head shouldn't be an issue for me now

Lol skinning a cat, I like the 12gauge approach, hit it with as many things as possible and hope it works