You don't really need to do that, just swiss cheese the valve cover. All the Spec Miata folks do it.

 

TOO LATE ............

I have two BP blocks. The stock block that I bent the rods in and the built block. For this the stock block was used. Started with a smalish bit and worked my way up. There's at least 1/2" of space behind the hole. Tapping the threads went fine. So Just after I get done Lordrigamus (Jeff) stopped by and wasn't looking an it more than 30 seconds and said "I don't think the starter's gonna fit where ya drilled the hole". Completely forgot about the starter. (nobody else thought of it either) It's right there where the BP is. SO, I drilled another hole above where the P is on the slant of the casting. This is actually a much better place. Even more room in this part of the casting. Clears the starter, no problemo. The old hole gets a plug. The new hole is at the perfect angle to vent gasses without any engine oil getting into it. Also win is this part of the engine block is a non stressed area and I don't have to worry about the first hole creating any stress cracks. I will post some pics tomorrow.

 

**** you and your lack of picturrrrrrrrrs!

(not that I'ma do this at any point in the future)

 

Lol'd pretty hard here.

For reals just get a catch can setup and be done with it.

 

I tried several versions of valve cover weld on bungs. They all ended up with oveflowing the catch can with oil. but it only ever did it on a race track. never driving it around on the street for testing.

FWIW I also now run with the ceramic coated pistons and the oil squirters blocked off.

Bob

 

OK, pics. As you know the first hole was fail, in the way of the starter. It will get a plug with JB weld on the threads. The second hole above the "P" also makes more sense. This is where it will go on the built block. Even with two vacuum cleaners going it was still a PITA to clean and ideally should be done at the beginning of a build. This would be impossible with the pan on. You couldn't flush all the shavings out the oil hole.



Here's the fail with the starter in place.

Some clean up stuff.


And finally the correct location.
Before:

And after:

 

damn the block looks thin. And the pics of you drilling it made my weinis twitch

 

I wonder why that web and pocket are there to begin with? It certainly does not seem structural.



Where does this plug go, into that cavity?

 

Keep us updated on how this works when you have it up and running. This is just down from the drain back through the block from the right rear corner of the head. Same area of the head that the PCV breather picks up in that and based on my experience the drain back doesn’t work fast enough to keep liquid oil from filling up the PCV baffles. I wonder if putting the breather where you are putting it will allow the back right corner of the head to drain back faster instead of pooling oil in the head.

 

agreed, i was kinda shocked looks really thin.

 

EO2K, I believe that's where Mazda machined the oil galley. You can see the bump in the block running past the oil filter. So it kinda makes sense that they would have to move the drain/vent out of the way.
Bob, theoretically yes. Both the vent and the drain hole converge in this same area, this would give the gasses a better path of least resistance.
If you have a 4qt system, how many quarts do you think are up in the motor trying to drain back?

 

That plug caps off the main oil galley, carrying the pressurized oil exiting the filter out to the main bearings. The passage which goes up into the head intersects with it.

 

Awesome, thanks guys. With the main oil channel there and the block drain above, that makes a lot more sense.

I didn't think this was that much of an issue with the BP. Its not like a FE series Ford V8 where you have to put an extra 1-1.5qts in the sump if you plan on running on the highway for any length of time. It makes sense though, blowby heading up and oil heading down, add to that boost, high RPM and high volume oil pump and you are probably outside the factory design envelope for drain operation.

As long as "we" are drilling holes in things, I wonder if its possible to open up the drain on the head/block/head gasket to improve the issue? Anyone tried it? I understand its a completely different application, but it seems to help the FE boys

 

In for results.

 

My guess is it could go as high as a couple quart sitting in the top of the head at times. Both driving the **** out of it and hard cornering reduce the ability for it to find its way down the drain back holes to the pan. I never could reproduce the serious breather issues on the street.

Also adding more and bigger breathers in the valve cover reduce crank case pressure from blow by but increasing the gas flow running back up the drain back holes to the head to find their way out the valve cover breathers tends to impede the drain back action. Imagine trying to poor oil through a funnel with somebody blowing on the bottom of it.

 

Nm, ignore this post.

 

So, does it blend?

 

Seems to be the same concept that is found of the Ford 2.3 SOHC

Hole in block > baffel can> Hose> PCV Valve> Hose> Intake ( Behind the TB)

This set up is used on both Turbo and NA, carb and FI

 

Sorry, not sure what blend means. Motor is almost done. The plan is to run this vent separately to atmosphere via a clear hose and clear container to see if it's playing nice with the rest of the motor. Next step would be clear hose to the rest of the catch can system and see how that works, then black hose.

 

In your defense, I should have said "So, will it blend?"

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But I was really just fishing for an update