Blowby-too much smoke!

[zmanoside]

Well I just bought this car. It's a 1970 240z with a P79 head and a F54 block out of a 81-83 280zx non turbo. The complete engine was rebuilt less than 6000 miles ago by a very reputable Datsun engine builder, Eiji Hosomi, out of Datsun Spirit. When I bought it the PCV was capped with a freeze plug and there was a breather hose coming off the valve cover. This was smokey and stinky since I've had it. The previous owner said that it had always smoked a little but recently had smoked more. Doing a lot of reading I figured I would uncork the PCV hoping to reduce the blow by coming out of the crankcase and setup a catch can with a breather filter on top. I did just that this morning and this thing is smoking even more now it seems. There is white gray stinky gas smelling smoke almost billowing out of the catch can breather filter. I drove it around the block and she runs SOLID. She just smokes a lot out of the catch can to where it's coming into the cab and it's unbearable. I've read and read. Rings are shot? Compression test? Leak Down? The car runs just fine I would think the compression is fine....I'm bumming. I have money left over from buying the car to cover fixing stuff, that I was hoping to break at the track, not to get it ready for the track! Any insight is appreciated. I need to hit the sac. Night shift sucks. I've been up since 3pm yesterday and I am beat!

[Zed Head]

Run the hose to the intake manifold like the factory did.  You'll need to seal the system so you don't suck too much air through the crankcase and screw up your air-fuel ratio.  It's not "P"CV until it has vacuum pulling gases through.

You might also confirm the "rebuilt by Datsun Spirit" story and get some details.  Wouldn't be surprised if they keep records on their work.  You could call them with the engine serial number.

Nighty-night.

[zmanoside]

Running triple mikuni carbs.

[Zed Head]

There's always a way.  If you don't want to use the intake vacuum you can use the Bernoulli principle - http://datsunzgarage.com/weber/

If you're using an air filter you can plumb both vents to it.  If you're using three air filters you could run a three-way T to each.  You could probably place the tube ends in front of the air horns and suck the fumes in that way also if you're running individual filters.  You could run a long hose out to the back of the car by the exhaust pipe.  I'd find a way to burn them myself.

[siteunseen]

Where is the PCV valve on your intake? I don't find one on this Cannon.

And that's something I've not even thought about before. I'm gonna put these on someday and will have to deal with your same problem. 

You should PM "blodi" and ask what he did. He's the one with the plugged block like your's I showed you earlier. 

[Zed Head]

Just had a similar conversation on a different forum, about a 4 barrel carb.  The carb manufacturers suggest the power brake port as dual purpose with a T.  So it would be the port on the right.  But this would run all of the blow-by through two cylinders.  I think that people run vacuum logs for situations like this.

Two problems really - one is what to do with the blow-by, the other is why is there so much.

[siteunseen]

There's a flat spot on the second runner that looks to be there for tapping. 

[Mark Maras]

2 hours ago, zmanoside said:

 There is white gray stinky gas smelling smoke almost billowing out of the catch can breather filter. I drove it around the block and she runs SOLID. She just smokes a lot out of the catch can to where it's coming into the cab and it's unbearable. I've read and read. Rings are shot? Compression test? Leak Down? The car runs just fine I would think the compression is fine....I'm bumming. 

 Don't assume the compression is fine just because it runs solid. There's reason for that much blow-by in the crankcase. I'd want to find out why, before I dumped it all back into the intake and then fret about, is there anything wrong, how long will it last. A compression test is cheap and easy.

[grannyknot]

Sounds like your rings.

[Patcon]

I suspect if Eiji built it, he has records of that. If there is a problem with the engine I would talk to him first. He has a very good reputation and has built engines for several forum members

[zmanoside]

The previous owner send over 10k of receipts along with the title of the car. Receipts from Datsun Sprit were included. The only reason I mentioned that is that's a big reason I'm so suspect that anything is seriously wrong with the engine. I will do a compression check. I'll look at the intake manifold and see if there is spots to tap into. I suspect not. It is a very short manifold, harada is the make. I was just reading the article about routing the blowby to the exhaust. That may be the best option if there is no other way to rid of the blowby and the compression is good. I'll see if I can talk to Les from Datsun motorsports too as his shop is two blocks from my house

[Zed Head]

Could be he got a rebuilt head from Datsun Spirit and a short block from California Datsun.  I'd go through the papers and try to suss out what's what.

 

Why does Datsun come up redlined for spelling?