cajunclicker

On my bro n laws 59,we have the old draft tube and vented valve covers and vented oil fill cap.Could I switch it over to a pcv valve type system.Someone told me that you could get a fitting that went in the hole where the draft tube was and it would reduce to about 3/8" hose that you could add pvc valve and run to your carb vacuum port.If so would you have to close off other vents?Also the vacuum advance for the distributor is not hooked up.Car seems to run pretty good.Should I connect vacuum advance?Help, suggestions appreciated.

JohnZ

Paragon has the "Dixie Cup" adapter for the rear block vent hole (to connect thru a hose and PCV valve to the carb baseplate), and the vented oil fill cap will serve as the "intake" point (along with the "vented" valve covers, although that's no longer necessary once the PCV system is set up).

If it's a 230hp, it originally had an 1110946 distributor with vacuum advance, and it should be connected to a full manifold vacuum source, as shown in UPC 6 in the 1959 Assembly Manual.

Frankie the Fink

All of the above from JohnZ is correct (of course).

You will also want to pick up a '63 right hand side spark plug loom. When you remove the road draft tube you will also loose the loom welded to that piece....

cajunclicker

Thanks for the responses,the numbers on my distributor are 1111109.It has vacuum advance but nothing is hooked to it nor are there any places where it looks like it could have been connected.It also runs good.I will connect it to a vacuum sour on carb probably.

ryan22

on a 66 L79...

2 related pcv questions- does it matter if the hose from the pcv is attached to the front or back of the carb ? Its an Edelbrock, no base plate.

and is it a MUST that the oil fill cap be vented since the intake point of the tube at the top rear of the block is being removed ? It has finned valve covers with no vents.

As always thanks for the enlightenment !

MikeM

A 66 L 79 doesn't use a vented cap. The tube at the rear of the block was plumbed into the air cleaner to allow for fresh air circulation.

I'm otherwise not sure I understand your question as that engine didn't use the Edelbrock nor the intake manifold it sits on.

GTOguy

With your current set-up (modified as it is) I would personally run a vented fill cap. No downside to it, with a bonus of better venting and less liklihood of leaking gaskets. Win/win.

MikeM

How do you fit a vented oil fill cap on a 66 L 79 oil fill tube? Even if you could, the PCV is directly under the filler cap. That would equal no circulation at all and absolutely no negative crankcase pressure.

MikeM

https://www.paragoncorvette.com/corv...atalog/c2/#4/z

JohnZ

Your PCV system should look like the photo below, except the 3/8" PCV hose that connects to the side of the Holley carb connects to the PCV port on the baseplate on the Edelbrock (don't know if it's on the front or the rear - I don't deal with aftermarket carburetors).

The large pipe from the rear crankcase vent hole in the block connects via a rubber hose to the elbow on the air cleaner base, and the oil fill tube uses a SEALED cap, not a vented cap.

GTOguy

It's a '59, Mike. Not a '66 L79.....unless I missed something..........

cardo0

Ryan just think of the Positive Crankcase Ventilation system as air flow system for the crankcase. U want an clean air source and that is usually a tube drawing air on the filtered side of the air cleaner filter - u can see it on most stock air cleaner housings - to the crank case (usually to the vlv cover). Then u need a connection from the crankcase air - usually the other vlv cover - with a PCV vlv in line to the intake. U could make a simple drawing but u just want a clean air source and then an suction exit to the intake. What the PCV vlv does is regulate the amount of air flow so it controlled and doesnt affect engine operation. Since your 66 doesnt use the vlv covers connections/fittings/posts u need alternate locations.

I dont see your system as stock so i think u can be creative here. Just remember u want a filtered source and that can be a port connection anywhere to the crankcase as long as a filter is on the end. The other end needs the PCV vlv in line and connected anywhere downstream of the carb. Since your '66 had a PCV vlv stock item i would stay with that part number PCV. U can attach it directly to the intake if u want but usually a better mix for all cyls under the carb.

A lot of owners will drill and grommet into the ends of the vlv covers stealthy for this. Also have seen a PCV vlv port drilled on the intake outside the intake runners where it can draw right from the lifter valley - but w/o a splash shield under the intake the PCV can draw a lot of splash oil from the lifter valley - not good. I guess u have to look your options over for connections to crankcase and exit to the intake (suction). Yea thats what hot rodding is about.

Hope this helps.

Betty Floyd

I just solved an issue with my 60 when I change it over to a pvc. It was pulling to much vacuum from the engine when I hooked it up to the carb. base. I about pulled all my hair out trying to figure out why it was missing and sucking a lot of gas. I just rebuilt a 327 for my car.

MikeM

I think you missed Ryan22 hijacking this thread. Post #5.

My response was intended for Rayan22. The Paragon illustration explains what he needs.