Technical Which oil filler tube do I need for my 327 SBC that is in the 55?

Hi,
I have a 1965 327 in the 55 and I am about to machine the hole in my intake for my oil filler tube in the front of the intake so that I can run a set of finned M/T valve covers without any holes. I am going to run a PCV system in the back hole of the block where the road tube use to come out and I have sources an original baffle for the valve valley. All I need to do is select the right oil filler tube for my intake. Some of the oil filler tubes look short and most of the ones on eBay look kind of long. Which oil tube should I use? I am also concerned that the oil filler tube might interfere with the upper rad hose that connects to the rad in the stock location. Do I really have to worry about this? I have attached an original pic of what the motor looks like right now just for reference.
Thanks
Jay

 

By the way the alternator is now on the drivers side of the motor with a more period correct bracket and short sbc water pump with a single belt. I would have posted a pic of that change but I haven't taken one yet.
Thanks
Jay

 

it's just a tube, buy the long one and cut it down if you need to. the breather cap just shoves in there, there is no lip or anything in the ones i've ever done. there is a couple different diameters too, get the filler in hand before you drill.

 

Thanks for the info man. I have been looking and I have seen a lot of them. I am just wondering about quality. Has anyone bought one recently and liked what they got. Some of them on eBay look like junk.
Jay

 

I've bought "junk" ones off Ebay. Never had a problem. It's just a thin steel tube.

 

You have a couple of PCV options. You can drill the back of the intake & install your pcv there, & put an edelbrock tube at the front. The cap on the edelbrock tube is vented, & this would be the intake of your PCV (same as 63-65 Chevy). In '66, they reversed the routing. The oil fill cap was now sealed (non-vented), & the intake breather was in the back. This is how I did it on my motor. I drilled the back of my intake for a standard breather, & the PCV sucks from the tube. Ordered everything from Paragon Corvette

 

Ya that is what I just ended up doing. I had just purchased one off ebay. Should work just fine and be here next week.
Jay

 

So you drilled the intake to allow air in? Do you have a pic of that? What fitting will allow air in without oil misting out?
I sourced the oil baffle that use to sit in the valve valley of the motor and I am planning on sticking a PCV in the back of the block where the old road draft tube use to be.
Jay

 

If i didn't have a factory one, I 'd buy the chrome MR gasket one. Beyond that, I've had more problems with holes being screwed up (Home Drilled)than the tubes.

 

That is what machine shops are for hopefully
Jay

 

Sorry, I dont have a pic. I drilled a 3/4" hole in the back & threaded in an air compressor vent (see link)

http://www.mcmaster.com/#breather-vents/=rcn7xp

No oil mist whatsoever. I dont have the motor installed yet - that was just my observation when I had the motor dyno'd. I also tried a k&N breather as well. I threaded in a male 3/4" nipple with a piece of red 3/4 clear tube - worked well.

http://www.summitracing.com/parts/knn-62-1100/overview/

 

I know it's April 1st but my head is spinning. If you have a block with a road draft tube, the stock Chevy baffle you want goes in the lifter valley area into a hole that is the beginning of where the road draft tube bolts on. Chevy also makes a road draft tube with the hose end on it that goes to the PVC the PVC will screw in the base of most carbs or a vacuum source then you are all set. If you look in a paragon corvette catalog you will find all the pieces and a picture of how it goes. They also have as was stated before a oil fill tube with a threaded bung for the PVC to screw right it, then hook up hose to a vacuum source. Good Luck

Pat

 

I just took a stock piece and cut it to fit the orientation of all my motor parts up top.

 

My old Weiand tunnel ram has a small hole where the tube goes - almost looks like a valve guide.

 

Maybe this style:http://www.ebay.com/itm/1967-Camaro...Parts_Accessories&hash=item35c5f2620b&vxp=mtr

 

Thats exactly what you need. Screw pvc in and hook other end to a vacuum source. Close off all other breather openings.

Pat

 

That's the tube I got. It uses a sealed (non-vented cap). The PCV screws into the side. The 66-67 are like that. 68 & up went to the PCV at the valve covers. He needs the 63-65 arrangement (non-FI) - which it looks like he now has as long as the tube cap is vented (IE: breather)

 

You need to have an inlet. The older blocks used the road draft tube provision. The makeshift mod without the road draft tube is to drill the back of the intake

 

You could weld in an aluminum tube but you may want to mill the hole in the manifold and make it any length you need.

 

Hi Pat,
This is what I am talking about. The hole where the road draft tube originally is you put a PCV valve in it. Air comes in through the breather vent on the oil fill spout and air goes out the back of the block with the PCV valve system that of course is connected to a vacuum source. Hope this pic helps.
Jay

 

You do not use air coming in and going out the pvc. The pvc is meant for a closed system with a screw on cap on the oil fill tube. If you have a breather and a pvc like you describe the pvc is virtually ineffective and it would also seem like a vacuum leak.

Pat

 

1934 you're wrong air does enter the system usually by the opposite valve cover with a hose going to the filter. with a filter on the tube and the pcv in place of the draft tube the system should work

 

Pat if we look at the set up right now in the car The valve covers that are on it have two holes. One hole in the passenger side is for the breather / oil filler hole and the drivers side hole has the PCV valve in it that is connected to the front of the carb. The breather allows air into the engine and the PCV sucks the vapor and recycles it to the carb.

If I was to cap the oil tube off how is the engine going to allow air to circulate through the system? I believe that without this circulation it is actually hard on seals and can lead to condensation build up in the engine.
Jay

 

What is the application for this PCV? I'm in the process of doing the same type of set up for my 327. At this time I have a "freeze" plug in the draft tube location with a hole in it for a valve cover PCV grommet. This looks easier.

BTW, I took an intake oil fill tube and drilled some holes in the OD. Then I welded on a tomato paste can to make my draft tube baffle. Then stuffed in a SS scrub brush. The oil fill tube is the same diameter as the draft tube baffle. Knocked it home and called it done.

 

I too have a frost plug back there right now and am in the process of setting it up properly. I actually sourced the original oil baffle (pic below) that is supposed to sit in the valve valley and connect to hole that leads to orginal cast hole. I will put the oil baffle in and then run a PCV valve with a rubber grommet just like the picture. The hose will come off the PCV and go to the large vacuum port infront of the carb. When I do it in the next couple weeks I will post pics. You idea of creating your own oil baffle did it work?
Jay

 

When I originally built the sbc for my '31 Tudor I had a breather cap on the intake manifold oil filler tube and no pcv at all. This was on a fresh rebuilt SBC with no miles on it. I came to find that the breather would drip out a very small amount of oil... so I slipped a tube sock over it, figuring that once the rings broke in the blow by would be less and then all would be good.

Shortly after I had some break in miles on the engine I ran it up to about 5 grand, looked in the mirror and smoke was pouring out the back of the Tudor.

I discovered that the mechanical fuel pump gasket (Holley) had blown, which blew oil on the headers, thus making all the white smoke.

The engine crankcase was building pressure, and the weakest gasket was the first to blow out.

I removed the filler tube and replaced it with one from the late 60's that had a pcv valve and a closed cap, not a breather. I then installed a Moon breather in the passenger side valve cover.

All has been well since this modification.

What I learned from this:

PCV, positive crankcase ventilation, requires an inlet for fresh air to enter and an outlet for the air / oil vapor to exit. The pcv valve is the outlet (sucking the air/oil mixture into the engine) and the breather is the fresh air inlet. If the breather isn't large enough the engine crankcase will build pressure, and the weakest crankcase gasket will blow out.

Hope you find this helpfull.

John

 

This is what I have been saying all along. ^^^^^^^^^^^^^^^^^^^^^^
Thanks John
Jay

 

Glad I could help. I didn't use the rear draft tube hole for the filtered air inlet because my block is a '72, and there was no draft tube hole.

Here's a link to P/N's for the 1966-1967 Corvette, which used the draft tube hole and the filler tube PCV: http://www.corvetteamerica.com/cf/d...ist.cfm?subcategoryid=x690&subcategoryid=x690

 

Nice! You can see right away that the air is being drawn into the motor through the air filter element! through the air cleaner assembly and PCV system is in the oil tube filler pipe. I am just reversing it. Air drawn into going into oil tube through the breather cap and the vapours are being sucked back through the road draft PCV system that I am putting together. Both are doing the same job.
Jay

 

Here is another way to do it using a pair of valve cover spacers. The PCV is the threaded '66-'67 unit. The breather is a K&N