What the heck is this in my block?

[Lonestar]

Tearing down my L16 for rebuild and I found this screen hiding under a plate in the Crank area, is this part of the engine or is it something you do to help oil filtering?

 

 

 

Also, would it be better to have the block powered coated before or after I send it to the machine shop?

 

[DAT510]

Thats for the block vent. 

[Laecaon]

Yep, filter for crank case ventilation.

 

Clean it since its out. I let my sit overnight in brake fluid... might be better ways.

[ggzilla]

Yes, that's the block vent baffle. The steel mesh separates out the oil vapor from crankcase air.

 

 

 

It is why the block has a rectangular bulge under the Breather Pipe on the left side

[Lonestar]

Oh ok, that is what I was thinking and I'm guessing there is no way to get a new yeah? This is what the side on my block with tube, where does this hook up at, on the valve cover?

[datsunaholic]

It hooks up to the PCV valve on the intake manifold.  But someone cut the tube; it should be 6-7 inches long.

 

[Lonestar]

Well what the heck...will that mess anything up?

[ggzilla]

Sure you can buy new from Nissan. But yours looks perfectly reusable.

[ggzilla]

:-)

[banzai510(hainz)]

those are dime a dozen.

 

you could plug your intake manifold part where this hooks up to untill you get the lobger tube or just make it longer. I like the PVC sytem myself and keep blowby stinking up the car/truck

[DanielC]

In this picture,

There is a small tube with a bend that comes off the main crankcase tube.  In 1971, Datsun used this tube as part of the evaporative emission system.

Both the PCV and the Evaporative Emission system do not cause the engine to lose any horsepower, and in fact can potentially increase your fuel economy.

The PCV system can also help reduce oil leaks from the engine, because it causes the crankcase to be at a slight vacuum during engine operation.

[Lonestar]

I` see, I would like to keep for the PCV, can the tube be replaced or it part of the block?

[DanielC]

The whole tube can be replaced.  it is just a press fit in the block, and may have some sealer on the joint.

You might be able to fins a new one at a Nissan dealer, probably special order, or you might have to remove one from another block.

[Stoffregen Motorsports]

If you do find a used one, make sure it fits. If they are too loose, you might want to use some 2 part epoxy or at least some good silicone to help hold it in.

 

If you don't want to run the PCV system, you could always "T" the valve cover breather and the block breather together and run the T to the air cleaner housing. This doesn't produce the same results as a complete PCV system, but it does pull a vacuum. I do this when I don't want a PCV.

[Lonestar]

Cool, good to know, thanks guys. I guess I'm on the hunt for a new pipe then. I'll have to call the OP on this and ask him when, what, or if he remembers why he did this and for what reason.

[ggzilla]

It's not for PCV - that was tacked on later.

The block needs ventilation.

 

Datsun A-engines had these tubes before they added the PCV system in 1970. At that time they used the block vent to connect the PCV valve. Previously they just dumped crankcase air out the tube, curved down to the bottom of the oil pan. It smelled and let oil fumes in the cabin every time you stopped.

 

With no tube hooked up and just a gaping hole, there's a good chance you smell like oil after driving your car ...

[Laecaon]

Mine hasnt been hooked up since July.

 

Was at work, and a customers car needed a hose, tada the one on my car was perfect.

 

Then I switched intakes, and gotta find new hose.

 

I dont smell oil in my car. Course then again, my engine is freshly rebuilt.

[Stoffregen Motorsports]

It's not for PCV - that was tacked on later.

The block needs ventilation.

 

Datsun A-engines had these tubes before they added the PCV system in 1970. At that time they used the block vent to connect the PCV valve. Previously they just dumped crankcase air out the tube, curved down to the bottom of the oil pan. It smelled and let oil fumes in the cabin every time you stopped.

 

With no tube hooked up and just a gaping hole, there's a good chance you smell like oil after driving your car ...

 

That's why I hook to the air cleaner. The small amount of vacuum produced helps pull the fumes and vapors back into the motor and out the exhaust.

 

***Note*** If you haven't had this breather system hooked up and then decide to run it to PCV, you may have a tough time tuning the motor. Often times, the oil gets contaminated with blow by fuel and when hooked up to PCV, this extra fuel vapor is burned off. With no PCV there can be a buildup of fuel vapor in the oil which can make the motor run a bit rich, until it burns off.

 

I would do an oil change at the same time to minimize this possibility.