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93 Civic HB SI, 95 Civic HB CX
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Is this a Z6? Do I spy a double gasket? Meaning, did you put:

Red RTV ----> Oil Pan Gasket <---- Red RTV

If so, can't tell you how many times I've seen this leak. RTV on two sides of a gasket is BAD PRACTICE, it is not needed!! The oil pan gasket should only need a little RTV at the block seams by oil pump and rear main holder, then around the crankshaft main 180's. Anything more is compromising the intended seal of the oil pan gasket rubber.

Clean and DRY surfaces (use copius amounts of brake clean and compressed air to remove oil before install) is all the pan gasket needs to seal effectively, with RTV only along the places specified in the manual.

Also, red RTV blows. It seriously has no place on an engine. I've never personally used it in my 15+ years as a tech, after fixing an unbelievable amount of previous work that leaked from other shade tree techs using the stuff. Get some Permatex Ultra Black, stuff made specifically for oil resistance. Red RTV naturally balloons when exposed to oil, not a good trait for an oil seal.

Fix this, then continue diagnosing. If you really have high crankcase pressure after this, your pan gasket wont leak, but your crank main seals will push out and let you know, making it seem like you have leaks from those seals, but will fix itself when the pressure dissapates. Although, main seal push out is HARD to do in NA form, unless the cylinder seal is seriously compromised.

More than likely, your double gasket job simply leaked and has failed. Your engine is probably fine.
 

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93 Civic HB SI, 95 Civic HB CX
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Id start by just replacing the sump gasket and following the correct procedure for installation. If you've still got your original gasket laying around don't forget to swap over the little metal spacers. Follow the torque sequence and review where Honda recommends putting the sealant ie: not on the top and bottom of the seal around the whole perimeter.
This :)
 

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93 Civic HB SI, 95 Civic HB CX
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DING DING DING
Well shit now that Ive paid extra attention to it and tested it, yes it smokes. Even when just revving it in neutral and blipping the throttle it does it. This really frustrates me as this was the reason I rebuilt and built the entire thing. How could this be with brand new valve stem seals. The shop that I took the head to said the guides were fine.

Im at a loss now. Even with my upgraded pcv system it still has lots of crankcase pressure. I even added the an10 adapter to the block.
I'm still not convinced you have massive crankcase pressure, maybe just high blowby.

What are your compression values again? Have you done a cylinder leak down test?

What is the actual crankcase pressure? Its one thing to have higher crankcase gas flow, which is pretty typical if you've upped compression, its another thing entirely to build pressure. Have you put a pressure gauge in the dipstick tube to see what it is?

Usually a manometer is used for this because pressures arent that extreme, using an inches of water column scale to indicate pressure:

Rectangle Measuring instrument Tool Font Thermometer


One inch of water = 0.036psi

But if pressure is massive as you say, a gauge that reads vac/pressure like those for testing engine vacuum usually have a pressure side to read like up to 10psi.

Gauge Tool Measuring instrument Font Auto part



Stick the hose in the dipstick tube and tape it off. Close the oil cap and leave your pcv setup like it is.

Then test pressure, at idle, and while revving. If pressure is as massive as you say, you'll see positive pressure values easily.

If you never see the gauge barely go positive (<1psi), you don't have excessive crankcase pressure.

With as much ventilation as you've provided the crankcase, I highly doubt you are building any significant pressure, more likely you just have a lot of blowby.

The only time I've ever experienced "massive" crankcase pressure symptoms was on large worn out diesel engines, and their customers complained of oil leaks. One I worked on had 20+psi actual crankcase pressure non loaded while revving before every main seal rolled over and bled off pressure, and 8psi at idle. This was enough idle pressure to blow the oil cap off the valve cover about 10ft in the air if you unscrewed it, slowly, with your eyes covered and your arm fully extended to unscrew it lol. Me and the guys at the shop did this about 20 times because it was fun, and went even higher if you revved it up haha.

THIS is what high crankcase pressure looks like. Anything less than 1psi is just blowby.
 
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