Was this hose originally painted from the factory?  I removed this hose recently as part of an overall engine "clean up" project and noticed that it appeared to have been painted a silver color.  Well, thinking that it must have been painted that way by a prior owner, I dutifully removed all the paint with a solvent.  Then, while perusing numerous L28 engine photos posted online, I found several that displayed this hose seemingly painted a "silvery" color... Just wondering if it was originally painted from the factory (and why).  Thoughts?

Also...it appears to be somewhat "clogged up" with "gunk"....how would you recommend a thorough cleaning of it?

 

I believe there is a flame arrestor inside that hose

I know that there is supposed to be a flame arrestor inside the hose that's connected to the valve cover...but hadn't heard that there was one in the PCV valve hose....is it possible that you're confusing the two (or that I'm not describing the hose I'm talking about clearly enough)?

 

1 minute ago, ea6driver said:

I know that there is supposed to be a flame arrestor inside the hose that's connected to the valve cover...but hadn't heard that there was one in the PCV valve hose....is it possible that you're confusing the two (or that I'm not describing the hose I'm talking about clearly enough)?

 

Possibly both...

I am more familiar with the earlier cars. I believe on them, the PCV is connected to the valve cover

Thanks for that....then it seems that the earlier Z's may be different than mine (78).  My PCV valve screws in on the bottom of the intake manifold and is connected directly to the crankcase via the hose I'm referencing...hopefully this link will show what I'm talking about...

 

https://whiteheadperformance.com/gallery/datsun-l-series-engines/#

ea6 is right, I believe.  And PAtcon is right about the flame arrestor but it's in the valve cover hose.

That silver PV hose is pretty big in diameter.  Just stick a screwdriver in there and dig out the crud.  And yes, they came in silver.  you removed original paint.

Thanks Zed...so...I guess I'll repaint it silver...Hi Temp Silver probably...as for reaming it out with a screwdriver, I'll give it a try, but due to the 90 degree bends at both ends,  and the relative brittleness of the 40+ year old hose (and the fact that replacement hoses from nissan are NLA) I'm not 100 percent confident that that will be effective...Hoping I can think of a way to ream it out with something more flexible than a screwdriver.

Carburetor cleaner?  Diesel fuel?

The silver paint is for heat I'd bet.

I've heard the belief that silver paint is special because it's conductive.

Haven't done a lot of research though, but "I read it on the internet".

14 hours ago, ea6driver said:

how would you recommend a thorough cleaning of it?

How about a bottle brush and some degreaser, simple green maybe for cleaning the inside.

Thanks for all the suggestions.  I'll definitely have to soak the inside of the hose good with some sort of degreaser/solvent before trying to ream it out with some sort of bottle brush.  A lot of the crud in there is hard and caked on...I'd be surprised if anything with plastic bristles is going to hack it...but, we'll see...I'll report back once the job is completed!

2 hours ago, Captain Obvious said:

I've heard the belief that silver paint is special because it's conductive.

Haven't done a lot of research though, but "I read it on the internet".

Wouldn't the silver paint be the opposite of conductive like heat resistant or reflective?