Should I drill a hole in my engine block?
 

I'm in the process of building my motor now. It has been discussed about how to vent the gasses from the block under boost. I was looking at the vent hole that is raised and located at the back on the passenger side. It appears that port and the one ahead of it connect together along the side of the block right where the BP lettering is and then goes down to a very large casting hole, you can see it when you look inside the block. Has anybody drilled a block vent hole there? It's high enough in the block that G-forces on the oil wouldn't be a factor there. 3/8" NPT with a 90 pointing up would ensure any stray oil would drain back. Has anybody else thought of this? Downside?

https://www.miataturbo.net/attachmen...ine=1351826252
https://www.miataturbo.net/attachmen...ine=1351826252
https://www.miataturbo.net/attachmen...ine=1351826252
https://www.miataturbo.net/attachmen...ine=1351826252

or just run ALLOFIT and let the block vent itself

AIDSthread.

why?
you can weld a single -12AN bung to your valve cover and not have any blow-by issues with a single catch can.

So how much boost are you running?

80psi?

No.

VTA block FTL.

yes

Drill a bigger hole, make it a 5 cylinder.

I was looking at the catch can thread and it seemed that BBundy was trying to come up with a solution for this.If I recall, you cot all the oil draining back down and its competeng with gasses that are trying to get to the valve cover. I've done the improvements to the valve cover. Boost will be in the low 20's down the road. (What's max psi a 2560 can be used at?) I just if seemed like a logical location then drill and tap it, install a plug, then down the road it could be of benefit later.

lol 20psi on a 2560

Vlad, OK, maybe I phrased that wrong. The question was what is the safe maximum operating pressure for the 2560. This spring I will be looking at an upgrade.
Sav, you say no, Bob was looking for a solution. I thought there was research to support that block venting was a good thing?

Just run a dry sump with a vacuuum pump. That is what the cool kids are doing now

Probably no more than 18 max and even then it will probably taper.
But even if you do upgrade later, unless you run something sized like FAIRYFLOWERS BORGWARNER S366 I just don't see the need for anything fancy. And drilling block for vents just seems like an insanely crazy idea.

Only one hole? Weaksauce...

Can we be constructive and support someone trying something new for a change? I want to see how this turns out. Do we know what that boss is there for and whats behind it? Its obviously an intentional casting boss either there just as a surface for the machinist to pick up on later or as a potential spot to drill for something.

I have been running with a hole drilled in my block for a breather port for a couple years now. It works and was an improvement I believe.

I drilled up by the oil filter just behind the #1 squirter though. This is the same location that Mazda cast in a block breather port on 1.6l B6-T and early 1.6l Miata blocks but they never used it on cars imported to the US they just put a rubber cap over the nipple. They removed the port from the casting for the 1.8l blocks.

I Drilled and tapped to a ½” NPT to -10 an and JB welded the fitting in the block. Runs up to a T with a line coming from the Exhaust side valve cover vent then to a catch can with oil separator. Intake side PCV port is blocked off.

I have the catch can setup where I can vent it to atmosphere or to a slash cut that has the exhaust flow pull a small vacuum on it. It works better and makes less mess to have the exhaust flow sucking the blow-by gas out the tailpipe though technically not legal pre SCCA GCR.

Bob

low testosterone post.

It takes someone with Balls to drill a hole in there block.

we already have Fae for that:fael: