2 holes on top of I6??

[714guy]

anybody know what those two 2 holes are for? there the one under the intake tube that goes across the the engine and there also two spouts front the tube that flows into the holes too.

Thanks

[CKlasse]

Originally posted by 714guy
anybody know what those two 2 holes are for? there the one under the intake tube that goes across the the engine and there also two spouts front the tube that flows into the holes too.

Thanks

I believe you are talking about PCV Valve - whose function is to relieve the vacuum created by engine compression. Make sure you clean these tube once awhile. Sometimes, it's filled with engine oil... and oil eats out rubber/plastic hoses.

[speedybenz]

CKlasse,

If your motor is getting a vacuum in the engine block, then you are one hell of an engine builder, HaHaHa.

Just let'in you know that most motors will have positive pressure in the engine block and so your PVC valve is there to let the positive out and then it closes to try to keep atmospheric pressure from flowing back into the block.

Typically engines with poor ring seal will generate lots of block pressure. One way race teams and other high performance shops deal with that is too put a vacuum pump on there motors to suck out the air in the engine.

This negative block pressure helps the piston rings seal better and allows the oil inside your motor to flow to the pan faster reducing parasitic drag on the crank, etc. The neg. pressure also reduces the effort it takes for the pistons to up and down, which is refered to as pumping losses.

I put a small vacuum pump on one of the 600cc Yamaha engine I built and it picked up another 4 HP from 10,000 to 15,000 rpm.

Jeff

[714guy]

i dont know about the PVC valve, these holes are big about 1 inch in daimeter each, maybe it is the pvc valve, b/c on friends then drilled two hole on his valve cover for the catch can.

[CKlasse]

LOL... Sorry for the confusion. The term 'vacuum' in my training is used to describe two different atmospheric pressures. It doesn't necessary mean 'vacuum.'

[speedybenz]

You want to keep the PVC valve. Maybe find a bigger one that flows more air.

But you want to keep the PVC valve and then route the tubing to a catch tank to keep the oil out of the intake and combustion chamber.

Oil in the combustion chamber will cause detonation real fast and cause lots of Hp to be lost. This is very important to you guys hooking up turbos to your engines.

Keeping the engine block/valve cover vents routed to the intake is a good thing if you have a working air/oil seporator in the system and a big PVC valve. The air/oil seperator keeps the oil out ofthe engine and the intake pressure which is negative can pull a slight vacuum to the engine block. Free Hp.

Jeff

[BongC36]

They are the Positive Crankcase Ventilation (PCV) valve ports. You might want to inspect them. On mine the rubbers lips are a little off-center and when I reinserted the little tubes beneath the main one they were slightly off, creating a vacuum leak and playing hob with my idle RPM.