Hello everyone! Proud new owner of a 1970 240z. HLS3007326 to be exact! A beautiful car. This is my first Datsun ever, and let me tell you, I am in love. I'm at work right now but I will add pictures asap! First off, the car has a rebuilt F54 block with a P79 head, both have less than 6000 miles on them. Issue at hand: The PCV tube coming off of the block is capped off with a freeze plug, the crankcase breather has quite a large hose that is venting directly to atmosphere and seems to have excessive blowby, which is pretty stinky (which is funny because one of my top reasons to buy this car was no smog checks!) and this can lead to ring failure I've read.. I've done my fair share of research on this and seems to point in the direction of a catch can of sorts. So, my issue is there is no PCV tube coming off of the block, at all. just capped. I cannot find this tube online anywhere (I can find the pcv valve and hose, but not the tube). Also, if and when I do find this tube, will venting this along with the crankcase vent to a catch can solve the problem? Will venting the PCV and the crankcase reduce the blowby? Why would the engine builder cap this off? Thanks in advance to any insight and help you can provide. I added a couple pictures 

--Zach

Edited March 29, 20168 yr by zmanoside
Added pictures

This guy has a plugged PCV on a motor he's running.  I think this link will take you to the 2nd page where he discovers it, then you'll have to read what he did???  You could send him a PM.  Cool car and welcome to the club. 

 

Hmmm. Confusing still. Some say it's ok to have plugged but most say have it vented. Looks like he chose to have it vented which is what I want to do. Looks like he got the pcv tube off of another block. Does anyone know where I can get one that doesn't have to come off another block? Can I just buy the tube?

If you consider what PCV offers, you might want to keep it.  It purges the crankcase of fuel, and exhaust, and moisture.  Keeps things clean.  The only real downside is if you're racing and you need every fraction of a horsepower.  It does allow some small amount of oxygen-deficient air (blow-by) in to the intake manifold.  It won't fix a blowby problem but will cover for it.  You have an L28, but it must have carbs.  Right?

Here's a link to MSA where they talk about the early PCV.  Later Nissan FSM's put the description in the Emissions chapter. http://www.thezstore.com/page/TZS/PROD/18-9050

Yea it has a L28 with triple mikuni carbs. I need to figure out how to fix this issue. The blowby is noxious and stinky. When I'm at a stop it appears as if my engine bay is smoking but it's just blowby. It's a lot. I need to figure out how to get that pcv tube

So I found one on eBay. Now is this thing welded in or just fit in?? And is there a seal? I'm running a F54 block from a 280zx so it should fit right in..

Edited March 31, 20168 yr by zmanoside

Tap it in with a rubber hammer.

Perfect thanks! Another question. After endless searching, for a catch can setup...do I route both the PCV breather AND the crankcase breather to it? or just a breather filter for the crankcase and PCV to the can? I'm looking at a dual baffled can with two inputs and a breather filter on top.

Edited April 1, 20168 yr by zmanoside