I have a 56' with a 57' 312 y-block. I do not like the open crank case vent and am considering plumbing the fumes to the air cleaner, as some of the next generation engines did. Does anyone see any problem with this modification?

Thanks.

 

Howdy,

MANY people have done that very thing. I'm planning to use a PCV valve from an OMC 460 marine v-8 on mine.

 

But there's a difference between a PCV system and just routing a hose from the draft tube hole up to the air cleaner. PCV is the safer way to do it, and more effective.

Rick, do you have pics of the OMC setup? Sounds interesting

 

They did? ......hummm, I didn't know that, (and lots else too) as albuq f1 says there is a diff between a PVC and a vent hose

anyway,........Welcome to the site.

It would depend on your engine condition and how much liquid vapor (oil) it is putting out, some liquid could congeal at the lowest point in your hose and if excessive would require draining. I tried that with a tractor that had real bad blow-by and it was too much for the air-fuel mixture.

What’s wrong with drip vent you have now?

 

I believe some of the last 292 y/blocks in 1964 had that system, I have one that has a different outlet from the top valley cover and The front left canister and tube have a cover plate. The rest of the parts are missing . I am trying to find out if this was factory installed as the valley cover doesn't look like it has been modifide .

 

Second thought maybe the guy that called [ the numbers guy ? ] could tell us ?

 

My '60 has a PCV valve, but I think it was an add on by the PO. There is a tapped vacuum fitting (normal size for a PCV) in the rear of the intake that goes to a PCV Valve that is in the rear of the valley cover. It seems to run fine but I don't know if anything underneath the cover has been changed.

 

I am just the opposite. I love open crankcase vents because if the engine develops blowby, it will not pressurize the crankcase and cause oil leaks from the usual places like the rear main, the front pulley, the rocker covers. The problem with the PCV system is that it was a stopgap solution for the smog police to make the engine crankcase sealed and oil vapor carried by blowby would be dumped in the air cleaner where theoretically the engine would burn the oil vapor and exhause components. However, except for passenger cars which have a low load and high vacuum at cruise speeds, trucks which have high loads on the engine will create so much blowby that the PCV valve cannot handle it all and the excess ends up at the air intake which is the original oil breather/filler.

This is why race engines all have open breathers and why trucks which carry loads or tow have to retrofit a unit called Vac-u-pan to eliminate their oil leaks. This is a siphon type system added to the headpipes which has a valve and two hoses go to the rocker covers. When a lot of exhaust is flowing, vacuum is created which then relieves the crankcase pressure. The blowby goes out the exhaust system and is handled by the catalytic converter if equipped.

So if you are allowed in your state to have an open crankcase, I would leave it that way. Advantages include a clean air cleaner, carburetor, less sludge in the crankcase, and no oil leaks propelled by pressure.

Regards,

Alan

 

Not sure the typical 50-yr-old 1/2 ton will have a heavy load much of the time, but your points are correct. Some of the more sophisticated PCV systems out there employ a very effective oil/vapor separator to prevent any problems.

 

Another double post....

 

Yesterday I was trying to remember who may be able to help you It's the guy refered to as " NUMBERDUMMY ", he's the ford parts guru. If anybody can help he's the one . JIM

 

No, but a 50 yr old truck is likely to have a lot of blowby from its 50 yr old rings and cylinder walls.......

Incidently, the crankcase vent on a Y block has a baffle and a filter (which in the case of a high blowby engine must be cleaned frequently), and on a flattie, the blowby from '49 on comes out of the intake manifold into a road draft tube.

Alan

 

Thanks for input. what is on the left side of the block where the open crank vent goes on your engine?
thanks skips 56

 

thanks for the input. my engine is in good shape, but i would like to get rid of the oil residue from the open vent tube that gets all over the bottom of the engine and everything in its path when driving. also would like to lower the fumes. thanks, skips 56

 

All CA cars/light trucks have the PCV system beginning in 1961.