I've finally finished the rebuild on my 324 engine and was thinking of using a PCV valve where the breather tube goes into the rear of the block using the baffle that goes inside the block and letting it breathe through the oil filler cap. I bought a new filler cap that has the foam rubber element in it from Fusick a few years ago. What do you guys think of doing that? Would the PCV system do a better job than the original breather tube? If it would work, what would be the best valve to buy? I've looked up some for early small block Chevys and wondered how they would work. Thanks for your comments.

 

This will work fine and is a good upgrade to prevent oil spewing from the road draft tube.

 

I think it's a none issue on a fresh rebuild. Are you getting blowby after the rebuild? I get no smell of blowby on my 324 after probably 30-40 thousand miles and mine is a convertible. You would think I would smell something with the top down and exposed to the open air.....Just my thoughts.... Tedd

 

I'm old enough to remember how black and greasy concrete highways were in the middle of the driving lane. The concrete would be beautifully white where the tires ran, and where the dotted lines were painted--but there'd be a slick black trail between the wheel tracks.

THAT's what happens when a zillion cars with road-draft tubes drive down the highway. The fumes and oil smoking out of the draft tube congealed on the highway, and made things actually dangerous right after it started raining. That used to be part of "Driver's Training"--roads were especially greasy just after the rain started.

ANYTHING that doesn't contribute to sliming the roads is a good plan. YES, install a PCV valve in place of the draft tube. Ideally, the fresh-air inlet side is routed to the air cleaner so that fumes are pulled into the engine no matter which way they're going through the PCV system.

 

https://dissolve.com/video/1955-clas...1-D423-417-450

 

Must be newer pavement. I remember it being WAY worse than that. Every rain would wash the loose stuff onto the shoulder, and it'd have that multi-color oil-in-water sheen to it.

 

Thanks Tedd, You've answered several questions for me during my rebuild and I appreciate them all. I'm not getting any smell, or blow by, or drip from the vent tube, but was just thinking that the PCV might be better. I did notice after running it for a good while a little smoke comes out of the oil filler cap. Don't know what that means if anything and doubt that a PCV would help out on that matter. I may run it for a while and see how everything goes and change to PCV if needed. As for some of the comments in response to my question about oil on the highway in the old days: I still see it now though not as much as several years ago. I think that better seals help out. However a young friend of my has a shop and I see quite a few oily bottoms when he has vehicles on the lift.

 

Thanks for your quick answer. I'll keep this in mind and get a good valve when I decide to change over.

 

I rebuilt the 324 in my 55 super 88 two and a half years ago, no issues, so put me down for a don't bother

 

My '56 324 is rebuilt also. Put me down as "don't bother" also.

 

The cap smoking a little is common. The way the downdraft works is air comes in through the vented cap (located at the front of the engine) and with air pressure exits out the rear through the down draft tube. with no air movement it can exit out the vented cap. Should you ever add a pcv valve you will have to somehow seal up your vented oil cap to make a sealed system..... Tedd

 

Hi Tedd,

After my rebuild I have excessive blowboy on my 324 after it warms up. Any suggestions?