Help what is this for ??

SBC 283 Looks to be a vent tube back of motor ?? It goes no where .

Thanks

 

road tube. for your crankcase vent sys.

 

Thanks , Ill keep it hooked !! This is because the original 283 had no breathers for valve covers ?? Just oil fill tube

 

Yup, the dirty old road draft tube. The air moving across the open end would draw the air out of the crankcase. The first true PCV was on the 307 in 1968, what year did the road draft tubes fall off the 283 and 327?

Bob

 

yes. you can run a pcv if needed out of the same hole.

 

My 67 El Camino had a true PCV valve on the 283.

The road draft tube worked with the oil fill tube breather cap to move air through the engine. It entered through the oil fill cap and exited at the end of the road draft tube as it moved down the highway. When parked wisps of oil vapor can often be seem coming from the breather. This system only works while the car is in motion....road draft

 

get rid of that grimey thing. its super easy to make a pcv set up with some grommets and br*** fittings. and think, you car wont be all oily underneath and the misses wont be *****ing about the dribbles in the driveway.

 

Yeah, that's a road draft tube on an earlier 283.

I think California started putting PVC valves in cars earlier than the rest of the country. I had a '67 Impala and it had a fitting back there in that same location that ran a hose up to the air cleaner. The way the PVC system worked on that 283 was clean air from the air cleaner was drawn in through the back of the engine there into the crankcase, then the oil fill tube had a PCV valve threaded into it, with a sealed oil fill cap. The PVC valve went to a vacuum hose to the base of the carburetor. When you shut off the engine, oily fumes from the crankcase would come up backwards and make a big stain on the air filter and onto a white mesh filter thing.

A few years later, Chevy went to a side to side PCV setup, with the PCV valve in one valve cover, and the hose to the air cleaner on the other valve cover.

 

If you want to make it a PCV system, you'll need the newer style oil fill tube that has a sealed lid and a threaded bung on the side.

The older road draft tubes worked from front to back, with clean air going in through an open breather at the front down through the breather tube, through the crankcase, and out the road draft tube. Air moving past the road draft tube supposedly made a venturi effect to **** the oily fumes out of your crankcase. Most of the fumes just linger around making an oily mess under the car though.

The '67 worked from back to front, with clean air coming from the air cleaner, then back through the hole in the block where they used to hook up the road draft tube, and then through the crankcase, then up through the oil fill tube, and then through the PCV and then to the vacuum port at the base of the carburetor to be ****ed up and burned along with the air fuel mixture.

I think it's worth it to have a working PCV valve. Older engines with the road draft tube were always full of thick tar like sludge when you pulled them apart. I think it's from blow-by from the cylinders mixing all kinds of **** in with the oil. Newer engines with a PCV valve look a lot better inside. I think the PCV valve system helps flush all that **** out of there a lot better.

If you could find a rear fitting from a '67 283 and a closed type oil fill tube up for up front, it would be really easy to hook up a PCV valve.

 

That is actually a "mouse block" to keep the mouse out.

 

I am ptting on a ****ster tri power unit with oil fill tube and no hole valve covers will this be a problem if I keep it the way it is or change over to pcv system or can I block it off ??

 

pound a freeze plug in that puppy and run a pcv valve from oil fill lid to aircleaner or carb base..

 

My 67 283 El Camino had a PCV valve that screwed into the base of the Rochester 2bbl. A hose ran from it to the fitting in the old road draft tube hole in the block. The PCV valves that screw into the oil fill tube up front on the Corvettes flow the opposite direction so if you build a PCV system with a Chevrolet screw in PCV valve always check the dirrection of the flow by blowing through it. They look the same externally but flow differently.

 

If I recollect - CA started requiring PCV systems in 64 and then it seems they demanded that anything made from 62 and up had to have them also. But, this is from the memory banks of an old hotrodder who is now suffering major depletion from a life of debauchery and decadence.

dj

 

I happen to like the ol road draft tube. If the engines in decent shape its not messy. IMHO