no vacumn to PCV valve,unidentified oil leak at intake.

[72farmer]

I just bought this 67 C-10 and i have some bugs i need to work out.The engine has some blowby but the PCV valve is not working.It is hooked to a port under the choke and when i pull the hose off going to the valve and stick my finger over the port on the carb. there is no vaccumn at all.Where can i get a vaccumn source for the PCV valve?I also have oil puddling at the intake bolts on the right side as shown in pictures.Where could the oil be coming from?

[dwaite72lnghrn]

The port on the carb should have vacuum all the time if it is below the bottom plates. The other sources on a stock manifold would be a tap between the carb and dizzy for the vacuum accs. and auto trans. Put your finger on the end of the hose going to the engine and rev it up and see if vacuum is there when you rev it.
If you have blowby the oil is from the engine being blown out the PCV hose onto the engine.
In the picture it looks like your power brake booster is in the manifold tap.

[cdowns]

oil leak due to no thread sealant on the intake bolts// common mistake by parts changers that dont install correctly

[grs]

My intake bolt was leaking on 69 truck. I just took it out, cleaned the bolt, cleaned the washer, and put it back in. That stooped the leak. I did not use any sealant. I guess it works sometimes without sealant, and sometimes you will need sealant. Let us know what does the trick.

[RichardJ]

That port on the Holley is for the original hot air choke. http://www.holley.com/data/Products/...l/199R8079.pdf

There should be a large port on the rear of the carb, under the bowl. You can use that or put a "T" in the manifold and share that with the P Brake booster.

[cparman]

Agree with all, I have had bolts leak oil and had to use thread sealant. The PCV needs to be attached to a vacuum port BELOW the throttle plats to have manifold vacuum. In one of the pics it looks like there is a fitting with a rubber hose going to the brake booster?? T into that.

[trusty72]

yeah the bolts are leaking, but when u get the vac problem fixed and negative crankcase pressure again the leak may go away. if not a little silicone on the threads will fix it.

[72farmer]

Bingo Richard I wish i had read your reply earlier.I pulled carb. yesterday and seen it was not a vaccumn port.

[junkyardjohn]

ANY INTERNAL COMBUSTION ENGINE HAS TO HAVE A OUTLET FOR THE BUILTUP INTERNAL PRESSURE. OTHER WISE IT WILL FIND ONE THRU THE PATH OF LEAST RESISTANCE. (LIKE A GASKET OR AROUNG BOLT THREADS) THATS WHAT PCV (POSITIVE CRANKCASE VENTILLATION) DO. BEFORE THEY WERE AROUND, MOTORS HAD A ROAD DRAFT SYSTEM THAT WAS BASICALLY JUST A VENT TUBE THAT EMTIED THE BUILTUP GASSES OR FUMES RIGHT OUT ON THE ROAD. PCV VALVES WERE A BASIC ANSWER TO POLLUTION BY ROUTING THE GASSES BACK THRU THE CARB, THEREBY BURNING THEM. JOHN

[cdowns]

sillycone is a very poor material to try and use as a thread sealer it these engines
a far better thing to use is "thread sealant" i personally prefer the teflon pste type sold in autoparts stores