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Discussion Starter #1
4G63 Block Vent

I have read a few threads on adding a block vent to the 4g63.
I know this not a new idea, and others have had done it before.
I also know that there is a kit so a block vent can be added in at the rear balance shaft timing passage.
Some of the locations I have seen used I did not like, or the size of the fitting being too small to be very effective.
After spending some time looking a block over, and looking at an assembled engine. I believe I found one of the better spots to install a block vent.

Since there is a factory vent from block to head, tapping into this spot makes the most sense to me. It is on the down side rotation of the crank, and is decently covered and high enough in the block not having to worry about oil slosh or oil return from the head. Also this should pull from the head as well as the block.


Also looking at an assembled engine, this vent looks to clear the starter and the intake support bracket.


I chose to use a 1/2npt 45* fitting with a 5/8 hose barb. This should give plenty of cross section and make an effective vent. The ID of the fitting is .530 The reason for a 45* instead of a 90* is so there will be less of a flow restriction through the fitting.

I scribed a simple circle for the location, then did a center punch dot


It is a basic drill and tap install.
For a ½ npt the drill size used is 23/32



Then tap a few thread, care needs to be used since this is a thin cast area.


Test fit the vent fitting and tap until the proper angle for the hose fittings face the desired angle.


Try not to extend the threaded portion of the fitting into the factory vent passage.
 

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Elite DSMtalker
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Im thinking of just using the balance shaft check bolt hole thats already down there, as long as you use a catch can that will seperate the oil mist out it should work I'm thinking.
 

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This is good,
I like this better than adding another vent on the valve cover, which can get tricky and expensive to do right.

Extra PCV is greatly needed on aftermarket setups pushing more boost. No more pressurized crankcase pushing oil dipstick up or pushing oil out of a weak oil-fill-cap seal.
 

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Discussion Starter #9
Has this been tested yet?
Since I posted this, I have sent out about a dozen blocks with the hole drilled and tapped, then plugged off with a pipe plug.

I have not heard of it being used at this time.


Im thinking of just using the balance shaft check bolt hole thats already down there, as long as you use a catch can that will seperate the oil mist out it should work I'm thinking.
Thats a common, done one, but that hole is a 10mm, also a baffle needs to be added in the balance shaft tunnel, due to the rotation of the crank and the oil roping off the crank gets slung right into that opening.

This is good,
I like this better than adding another vent on the valve cover, which can get tricky and expensive to do right.

Extra PCV is greatly needed on aftermarket setups pushing more boost. No more pressurized crankcase pushing oil dipstick up or pushing oil out of a weak oil-fill-cap seal.
Agreed, it can add a couple hundred to a build price by the time you get the fitting and have it installed.



I love the fact that this gives us an option that will maintain a OEM looking valve cover.



BogusSVO <--- Love this guy. Always contributing to the community.
Since this is under the intake manifold, it helps keep more of a "stock" apperance.


Ripper.... you're making me blush.
 
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