I spent the winter installing a turbo on my 91 1.6l. I finally got around to taking it out for some tuning sessions and saw a puddle of oil under it after one of the runs. Turns out the dipstick tube was leaking. I replaced the o-ring and it still is leaking. After hearing some advice from a local site I decided to pull the dipstick out of the tube slightly to see if oil would come out under boost, I figured that this would tell me if the bottom end was being pressurized or if the o-ring on the dipstick tube was just bad. Turns out oil squirted out the top of the tube leaving me to believe that the rings are either on their way out or are shot as is.

Is there a way to vent the block to maybe relieve some pressure? I really wanted to track this thing this summer but I'm not putting the time and/or money into pulling the motor and replacing the rings.

 

i had this issue once before on my old 93, it ended up being a combo of both the one way valve between the intake and valve cover not working, and that on the hot side, i had just placed a filter.

I got the one way valve that was made for the turbo version of that engine, the 323 or 626 (cant remember now) and ran a peice of tube from the valve cover to post filter/preturbo so it would help in creating vacuum there too

When i got the 97 turboed, I made sure to redo this

 

Two things. First, what he said. often its a bad PCV, not a blown set of rings. Honest to god I recomend just putting an oil catch can on there rather than routing it to the intake. Its only routed into the intake for emmisions and frankly its not doing the Earth any good that way in the first place.

Second, old trick. Crimp the end of your dipstick tube with some pliers a bit. Holds the stick in place and helps prevent that.

 

https://www.miataturbo.net/engine-performance-56/another-oil-catch-can-thread-46833/
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What part is recommended to crimp? Going through this problem now with a boosted 1.6. Any pics please

 

Wow, talk about a necro thread, did you notice the 2010 date?
Anyhow, the recommendation above has yet more info about all of this than it did back in 2010