Crankcase Breather?
 

My bone stock '72 350 has a 3 inch 'hat' om top of the carb, and the 3 inch air cleaner. There's no crankcase breather in the air cleaner. But there is a tube from the valve cover that goes into the hat, and there's no breather. See the pic... I have no reason to think this is not stock, just never seen it before. Seems like without the breather it's just going right into the carb...

Re: Crankcase Breather?
 

It already has filtered air going into the valve cover from the air cleaner.

Re: Crankcase Breather?
 

Ah, ok... I had the airflow reversed in my head. Thanks!

Re: Crankcase Breather?
 

My C10 72 is just like that. Though, I don't have a fancy oil fill tube - is that thing stock? if so where do I get one for my truck (and where the hell did it go??)!

Re: Crankcase Breather?
 

Hello, I think that the "Hat" is called an air cleaner spacer, The tube allows air the engine is sucking in to come from the crank case thru the engine and the flame arrester to the tube.
The spacer, tube and arrester are stock.
I am not sure if its called a flame or spark arrester but that's the part between the tube and the valve cover.
Hope this helps. K.E.N.

Re: Crankcase Breather?
 

that helps me - thanks!

Re: Crankcase Breather?
 

Rich, I think those oil filler tubes were only stock on the C-50 and C-60 trucks.

Re: Crankcase Breather?
 

You have it backwards.
Air into the motor from the riser thru the hose and arrestor into the valve cover. The air combines with moisture and gas fumes and then it’s all pulled out the other side by the pcv valve.

Re: Crankcase Breather?
 

It is all factory. It works both ways. At idle or cruising with high vacuum it passes air into the engine to fill the void from the PCV valve. At heavy throttle & little or no vacuum the blowby gasses pass through this tube into the air stream.
George

Re: Crankcase Breather?
 

So the OP got it as an option?? - his doesn't look like a C50/60 - I am not even sure I seen anything above a C30!

Re: Crankcase Breather?
 

As far as I can determine from date codes, this truck is 100% stock, and the engine is original. The filler tube looks same age as rest of engine, so I really don't know...

Re: Crankcase Breather?
 

All stock. Have pics but of course can't find the one I want at the moment showing that setup. On a '71 C10 Custom. 350, Rochester 4bbl. Oil fill tube on the drivers side with the bracket that bolts onto the intake side of the valve cover. Passenger side flame arrestor and tube into the spacer under the air cleaner.
Truck is a bone stock farm truck that hasn't been messed with. Sitting in a shed for 10 years...
The usual story, don't want to sell it, the grandkids are going to restore it. That was three years ago and it is still sitting there, untouched.

Re: Crankcase Breather?
 

Just to derail this thread one step further, I'll add my own experience from my grandparents 1957 Thunderbird basketcase. When the time comes, that truck will likely be sold fast and cheap. The grandkids won't even be consulted. Because if they were, they either wouldn't want to pay what the other family members think it's worth, there would be conflict when two people wanted it, or they would say they want it but don't actually have the ability (space, tools, etc.) to work on it.

Moral of the story for the grandpas and grandmas, make a plan, write it down, talk with your family before it's too late, and think about not waiting. My grandmother made an effort to find out what her kids valued, and then was able to share a memory and gift the item. This made it more than just "valuable stuff".

Re: Crankcase Breather?
 

That fancy oil tube came with ac only trucks o

Re: Crankcase Breather?
 

For what years? My '69 C20 with 350 and A/C has never had one. Based on junkyard observations, I was thinking it may have been a 71/72 addition. Maybe this subject would benefit from a separate thread.

Re: Crankcase Breather?
 

The oil fill tube was stock on K model trucks. I'm not sure on the years, but my 72 K10 came with it.....

Re: Crankcase Breather?
 

This is exactly how my '71 is setup (no idea if stock or not) except I do not have the idle solenoid (which I want to add). If I understand this correctly, the breather simple burns blow by gases by dumping into carb. I have the same oil fill tube. Where does the power for the solenoid come from? My truck has A/C

Re: Crankcase Breather?
 

Bad info...

Good info...

We just listed a couple of OE used 71-72 small block optional oil filler extension tube setups and some GM NOS filler tube "specific" grommets in the below linked f/s thread, we gave you an option on buying one of the setups. If interested, have a look and confirm/pass in thread. Thanks, Mel :chevy:

http://67-72chevytrucks.com/vboard/s...d.php?t=818966
.

Re: Crankcase Breather?
 

These oil filler extensions accompany NOS power brake units so it may be related to power brakes. Also, these are present with AC if I’m not mistaken. As an aside, the rubber plug was originally painted with the motor. The extensions were added on after motor assembly/paint.