So, for my setup would I be ok to ditch the pcv and route only that side to a can VATM and leave the driver side the way it is?

I just don't want to keep blowing oil into the intake manifold. I removed it the other day to clean and paint and had alot of gunky oil build up.

Instead of a catch can, I plan to add scrubbers in the cam cover:
https://www.miataturbo.net/engine-performance-56/cam-cover-blowby-flow-crankcase-pressure-tiny-hole-modification-54742/

I also plan to enlrage the tiny 1/4" valve cover hole in the baffling, through which all the blowby gases are forced to flow.

Been there done that. Works fine on the street. Full cornering grip on a winged car and full throttle track abuse and it still doesn’t work. Turn 5 and I think 6 specifically up the hill at Laguna loads up oil in the right back corner of the head I think and spooges it into the baffle a heavy amount.

Bob

I didn't really think that setup would be good enough for you.

I will say it looks like the VVT cam cover looks as though it is set up a little better. I’m using a 94-97 valve cover on a 99 head and the opening for the baffle in the cover is further in the back corner and it is just above the raised hole in the head to the lower portion of the block designed as the main path for blow by gas to get from the lower to the upper crank case. My theory is in a hard right left turn with a lot of acceleration the oil in the top of the head all goes to that corner and blowby gas ends up pushing liquid oil into the baffle rather than just vaporized oil particles.

Bob

So for AN fitting attachments, what sizing is the best.. -10 or -8. I imagine that the holes in the cover aren`t even close to the size of -10.

drill it out.
your going to move the same volume of air... do you want high or low velocity to move that volume?


go -12 if you CAN.

I used -8 for the valve cover -10 for everything els. total guess on my part.

Bob

I bored my breather out to 1/4" NPT, and used 1/2" hose:
https://www.miataturbo.net/showpost....3&postcount=20

-8 is 1/2" hose. 1/4" NPT has a smaller hole in it than my -8 AN weld bungs though I believe.

Bob

I measured the i.d. of my fittings, and they were about 0.38" ~ 0.40". Ditto for typical 1/2" barbs. The enlarged hole inside my valve cover is 0.40".

Where is that $150 "racing" catch can system?
I can't find the post for the life of me......

Ahh bbundy posted it in another thread:
http://www.mann-hummel.com/industria...BVFLGOcGNM.pdf

THIS is what my car has (hopefully) and not a bad engine.
Now I only need to fix it's 2nd issue too: 6500rpm flat spot.

Btw venting to exhaust is working great

But

Despite no smoke clouds you will get a greasey rear bumper after a month or so.

Mine was sucking oil out the catch can and making huge clouds of smoke the first time I tried it on the track. A combination of some on off throttle, high G left turn, with hard acceleration off a left hand corner puked lots of liquid oil into the catch can faster than it would drain back.

Solution: eliminated the vent on the intake side that was the stock PCV port and problem dissapeard. I’m just using the valve cover vent that comes out on the exhaust side which is baffled to the center of the valve cover. I also have a vent hose going into the side of the block by the alternator same location as some 1.6l blocks have a capped off port. I also found a PCV valve that fit perfectly to work as a check valve in my return hose to the very bottom of the pan.

What I learned is the baffleing for the PCV port in the valve cover dosn't work. oil must pool up in the back right corner of the valve train where the stock baffling has its inlet on that side.

Bob

so basically the catch can is not necessary? I'm still a little unclear on how you have the return line. basically just a line with a check valve between alternator port on the block and a port you made in the pan?

yup you vent the alt4ernator VTA

and

the catch can to the power steering pump

Quick stupid question. I'm still out of a job and I need to fix my blow-by issues, can I get away with blocking off the IM port and placing a filter on the hole in the intake side of the valve cover?

I doubt it. When I ran with the intake side blocked I was puking out oil from the driver side. You should just vent both sides to a catch can like setup.