Home Built Z 'Full video build'

[Zed Head]

4 hours ago, wheee! said:

Jeff, your routing of the crankcase PCV and the valve cover breather may be wrong. The PCV outlet on the block is out only, and the valve cover vent is bi-directional . The little oil catch can you set up is an “in and out” you have one of the lines on the “out” port which defeats the filter mechanism inside. You will also have no positive breathing through the filter in the can! When all pressure is going in, it will effectively block ALL BREATHING from the block. If you install a filter on the "out" port and then route the valve cover hose to the top of the can, the air can move freely to the valve cover and still get clean(er) air from the can. The block will then be able to breathe.

I couldn't tell how that catch can works.  If both ports are open, with no check valves, then it seems like he just moved the typical little breather down below the manifold and off of the valve cover.  Really, he could have just blocked the valve cover  port and run the one hose to the catch can.  It wouldn't be "positive" ventilation anymore, there's no vapor flow, it would be like a 1960's set up.

I don't think Nissan gave a crap about crankcase ventilation until EFI days.  They don't seem to write anything about it until then.  Here's a diagram showing gas flow.

I had a friend who rebuilt the engine in his Camaro and it would just spew loads of blowby out of the valve cover breather when he got on it, until the rings broke in and sealed.  The whole point is "what do we do with this blowby?".

[wheee!]

Nice post Zed. I know about the container he bought as I am looking at the same one for my build. It is a "in" and "out" system with a small filter on the "in" side inside the can allowing the "out" side to have oil free air. There is a port blocked off on top that you can add a small filter to allow the can to breathe if you are not recirculating.

My thoughts being that the valve cover can go both ways, so use the top "oil free" hole and allow any residual oil vapour to fall gravity wise to the bottom of the can while it is in "valve cover output" mode.

Edited February 8, 2019 by wheee!

[Zed Head]

The video kind of "blew by" it but he did show the catch can with a filter on top, at 3:31.

 

[Home Built by Jeff]

1 hour ago, Zed Head said:

The video kind of "blew by" it but he did show the catch can with a filter on top, at 3:31.

 

I was about to link that, but yes that is how I have set it up. I know the catch can has 'IN and OUT' points but with the filter on the top they will both be IN. I have not fitted a PCV though, so I may look into that to see if it is going to be an issue with out it, but I can probably find one.

[wheee!]

With the two hoses going to the can, and a filter on the top like you have it, you should have little issue with the carbs. Fuel injection on the other hand....

[Zed Head]

You'll probably need to do the rears again.  When I had my front calipers on the wrong side I couldn't generate much pressure or flow because the big air bubbles up front took all of the travel.

[Home Built by Jeff]

2 hours ago, Zed Head said:

You'll probably need to do the rears again.  When I had my front calipers on the wrong side I couldn't generate much pressure or flow because the big air bubbles up front took all of the travel.

I didn't bench bleed the masters either, so I realise now that I am bleeding the lines, but the piston of the master has not been bled. I will try to get a power bleeder and an assistant and give it another go.

[Captain Obvious]

No technical input (at this time), but props for the Predator reference.  

[Home Built by Jeff]

12 minutes ago, Captain Obvious said:

No technical input (at this time), but props for the Predator reference.  

Haha, you are the first person to actually acknowledge it ? 

[Captain Obvious]

Glad to help in my own little way!       

[Home Built by Jeff]

In this episode I try my luck at cutting and buffing the 680.

 

 

[wheee!]

Did you use any kind of backing to your 2000 grit or just your hand?