I just finished rebuilding a 22r. It had a massive oil leak when driven at freeway speeds-- I'm assuming due excessive crankcase pressure. I had just bought the truck, when after driving it for an hour on the highway, it spun a bearing due to oil starvation. At the time, it didn't seem to leak when traveling below 50.

Now I've finished the rebuild, and it is overpressurizing the crankcase in a big way. Oil is laking from many of the freshly permatexed gaskets. Blowby is coming out of the fresh air breather. I have not changed the pcv yet, but it does rattle, and has been cleaned.

I'm really at a loss for what to do because I've just replaced all the rings, bearings, etc. and permatexed all seals, only to have oil piss out of every single seal.
I did a compression test and got 125 psi, which is lw for a 22r. Still, I'm pretty sure the rings have not completely seated yet. It doesn't seem to be burning oil, just leaking from excessive crankcase pressure. Thinking about maybe doing a leakdown test, or just blowing some compressed air into the cylinders. Wondering if it might be something stupid, like valve timing being slightly off. But it runs very well apart from the high crankcase pressure.

Any help would be great.

That's a lot of blow by. Sounds like the rings are too loose. You did stagger the ring gaps, right?

The easy thing to check would be clogged/stuck PCV valve.

A compression check will tell you a lot.

You're not going to like this, but huge amounts of well pressurized blowby rarely comes from engine compression. Usually its from a spun engine bearing. The bearing spins, vaporizing the crankcase oil, producing huge amounts of crankcase pressure.

A big key in this is the appearance of the blowby. If it's hazy appearing, it's almost assuredly from oil vaporization. If it's crystal clear, then combustion gasses are more likely.

I had the same problem when I got my reman 22RE. I thought it was the rings, so I checked compression and did everything I could and possibly think of, and yet the compression was good, the oil clean. Finally, I pulled off the valve cover (I can't remember why) and found that I had a defective gasket- it was distorted badly in the back allowing air to get in (pressurizing the crankcase) and oil to get out in large quantities. I was losing 2 quarts per day, though only at highway speeds. Just a thought!

Did your rebuild include machine work, new pistons and rings?

If so, I'd do a leak down test and see if you're pressurizing the crankcase.

Yeah, I haven't yet gone the way of doing a leakdown test. I was thinking about actually blowing some compressed air into the cylinders one by one. Sort of a poor man's leak down test. If I can hear where the air is flowing, I might have a better idea what the problem is.

The rebuild di include machine work. I had the block hot tanked and inspected. It was not magnafluxed, but the machinist mic'd the cylinders up to make sure it didn't need to be bored. The engine had only 109,000 miles on it, and he said the lower end looked good. It had spun a bearing and consequently wore out the bearing mating surface on that connecting rod. I wound up getting a reground crank and a replacement connecting rod.

Had a professional valve job done shortly before spinning the bearing. My feeling is that the oil problem was pre-existing, but since I rebuilt the engine, it actually seems quite a bit worse.

I'm puzzled, though, because clearly the crankcase is getting pressurized--it shoots smoke out of the fresh air breather even at idle! But the cylinders are holding 125 psi, which isn't terrible, and the rings aren't done seating yet.

Its been too cold here in VT to do much on it, but I've got to get this truck going. I've been driving my in-laws car for 4 months now!