“Inside” part of road draft tube

[Norris McCarty]

Where can I buy the part of a road draft tube that comes up from the block up to the intake manifold? My 53 Merc is running an early Navarro manifold so there’s no road draft setup.
I pulled the manifold today in order to install a PCV setup under the manifold and found that the tube in the lifter valley had previously been removed.
I’ve looked, but can’t seem to find that tube for sale anywhere.
Even if I went with a late model manifold I’d need the tube.
I suppose I could find a freeze plug the correct size to fit the hole in the block and weld a fitting for the PCV line on it but I’d much rather find the tube that should be there to weld a cap on and T a fitting to connect to the PCV valve that’s connected to the underside of the manifold.
Thanks
Norris

[adileo]

Norris try the swap meet section here. Click link above and do a search.

[Norris McCarty]

Thanks....looked there. I also put it in the parts wanted section.
I think the tube has an OD of 1 5/16”.
I don’t imagine many of these got discarded or saved.
Maybe I can find an old block around here....doubtful

[flatford8]

I probably have one in a bad block around here some where. It’ll take me a couple days to dig it up. I’ll PM you when I find one.......Mark

[Norris McCarty]

Thanks Mark. Since my car is not stock, I may not know what I’m talking about.
Is the tube that comes up though the manifold from the bottom of the lifter valley(hole in right front of block lifter valley)one piece? Is there a grommet where it runs through the manifold?
I was thinking that it runs from the hole in the block to the bottom of the manifold then another pipe attaches to the top of the manifold and then down?
I apologize for my confusion.
Thanks

[30-9]

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This is a road draft tube:

https://www.fordbarn.com/forum/showt...ght=Draft+tube

Saw in swap section.

[tubman]

I don't believe that is what he's looking for. When you remove a proper intake manifold from an 8BA, there is a straight vertical pipe about 5" long the fits into a hole in the valley and also into a matching hole on the bottom of the intake manifold.

I think that's what he needs, as it appears that someone removed the original to be able to run an early manifold. If I am wrong, well, I'm wrong.

[Norris McCarty]

Ok, all I need is the tube that goes into the hole in the right front of the lifter valley. My early Navarro manifold does not have a hole in it for the road draft tube. I’ll be cutting and capping the tube off 4” or so above the lifter valley so I can put a fitting and hose on it to go to a PCV valve that’s tapped into the bottom of the intake manifold for vacuum.
Here’s the hole:

[Norris McCarty]

Correct TUBMAN.....Thank you
Here’s what I’m trying to do:
https://www.jalopyjournal.com/forum/...ve2-jpg.24680/
Not my picture.....just a pic of what I want to do.

[51 MERC-CT]

If you have an original road draft tube, a portion of it can be reworked to fit.

[Norris McCarty]

Thanks.....I don’t, but can probably find that piece and build one if I have to.
I would not have known that if you hadn’t brought it to my attention!

[tubman]

There is a website called "OnlineMetals.com" that sells small quantities of metal products for reasonable prices. You may be able to find what you need (1 15/16" steel tubing?) there. I would also suggest trying to find a steel "Freeze Plug" the proper size to cap the tube off. There is a site called "FreezePlugFactory.com" that will probably have what you need, but unfortunately they are not "small quantity friendly". You might also try your FLAPS or maybe Dorman.

EDIT : It looks like 1 5/16" is not a standard tubing size. Your best bet is to find an original. I am sure someone on here has some laying around. I probably do, but it would probably take me days to find it. A "cup" freeze plug is probably still a good idea to cap it off.

[Norris McCarty]

Thank you sir!
It’s 1 5/16” best I can measure in that hole!
That just reminded me that I have some snap gauges.

[V8COOPMAN]

.

Hey Norris....."Heard" and I just finished doing a PCV valve on his new 8BA with an 'early' intake manifold. You're correct.....there is an internal tube that originally goes from bottom to top. One twist that we decided to overcome was to devise a way to hide the PCV valve, yet have the ability to service or replace the valve WITHOUT the need to remove the manifold.

We cut that vertical tube roughly in half. There is a DORMAN freezeplug that fits tightly into the top of that tube, into which we drilled an appropriate hole to accept a bulkhead fitting with a compression nut and ferrule for the copper tubing. Click the link below for our entire thread with a parts list, including that DORMAN freeze plug number........plus a lengthy description of our process....plus lots of pictures. You'll find a tube shortly....I can't believe "tubman" doesn't have half a dozen of those laying around on the floor!! Good luck!! DD


https://www.fordbarn.com/forum/showthread.php?t=284487








........

[msstring]

Not sure if I should pirate this string but it lines up with a question I was going to post. So will give it a shot. What size PCV valve do you guys use? Or, how do I know if I am getting enough air flow? I have a 1950 8BA, I used my original draft tube assembly and drilled a hole in the tube and treaded in a hose nipple. Then capped off the original draft tube at the bottom. From the new nipple I ran a rubber hose to catch can then to a PCV then to the manifold. The plumbing all seems to work out. But I don't know if I am getting proper flow through it. I'm not pulling a notable vacuum in the crankcase. I used a heater hose to make a sealed fitting on the dipstick.

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[51 MERC-CT]

Originally Posted by msstring

Not sure if I should pirate this string but it lines up with a question I was going to post. So will give it a shot. What size PCV valve do you guys use? Or, how do I know if I am getting enough air flow? I have a 1950 8BA, I used my original draft tube assembly and drilled a hole in the tube and treaded in a hose nipple. Then capped off the original draft tube at the bottom. From the new nipple I ran a rubber hose to catch can then to a PCV then to the manifold. The plumbing all seems to work out. But I don't know if I am getting proper flow through it. I'm not pulling a notable vacuum in the crankcase. I used a heater hose to make a sealed fitting on the dipstick.

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This is the way I checked for vacuum using the oil fill tube as the source.

[Norris McCarty]

Thanks V8COOPMAN. I needed that!

[Ross F-1]

FYI the original p/n for the tube is 8BA-6759. Google didn't find any but Dennis C. may have it in their stash of NOS parts.

The oil fill tube for an 8BA is 1.3695 OD, might be worth trying, those are widely available.

[Norris McCarty]

Thanks Ross!

[19Fordy]

Can you make that internal tube using a piece of copper tubing or a sink drain pipe?

[Norris McCarty]

Thanks 1940.....I'll look into that also.

Wayne at Dennis Carpenter says they have one in a NOS part #! I can't order it until Monday because they are running a short crew today(understandable). I'll call them Monday morning early!
Very helpful folks.....just like the Ford Barn!

[msstring]

[QUOTE=51 MERC-CT;1956741]This is the way I checked for vacuum using the oil fill tube as the source.
Great idea!

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[Norris McCarty]

Special thanks to Mark, Bob and Richard.......I have had offers from all three to send me the tube I need!
Great bunch of guys on this forum!
I’m looking forward to “paying it forward”
Norris

One more question...what is the inside diameter of the road draft tube hole in the late manifold. I’m going to have that hole machined into the boss on my early manifold.

[V8COOPMAN]

Originally Posted by Norris McCarty

Special thanks to Mark, Bob and Richard.......I have had offers from all three to send me the tube I need!
Great bunch of guys on this forum!
I’m looking forward to “paying it forward”
Norris

One more question...what is the inside diameter of the road draft tube hole in the late manifold. I’m going to have that hole machined into the boss on my early manifold.

Why? DD

[Norris McCarty]

That’s where I’ve decided to put a pcv valve. The way my manifold is designed, I’m going to need to pickup vacuum from each side of the manifold.....so I don’t lean out any cylinders. I don’t really want all of that “plumbing” under the manifold. It’ll be easy to run a line from each side of the manifold below where the center carb would go and T it just before where the capped off road draft tube/pcv valve will be.
It won’t look as clean, but it’ll sure be easier to troubleshoot if there is a problem with the valve.
I’m also considering just using a metal pcv valve that has a threaded end and threading a small hole in the boss instead of a full-size road draft tube hole.

[51 MERC-CT]

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Originally Posted by Norris McCarty

That’s where I’ve decided to put a pcv valve. The way my manifold is designed, I’m going to need to pickup vacuum from each side of the manifold.....so I don’t lean out any cylinders. I don’t really want all of that “plumbing” under the manifold. It’ll be easy to run a line from each side of the manifold below where the center carb would go and T it just before where the capped off road draft tube/pcv valve will be.
It won’t look as clean, but it’ll sure be easier to troubleshoot if there is a problem with the valve.
I’m also considering just using a metal pcv valve that has a threaded end and threading a small hole in the boss instead of a full-size road draft tube hole.

Does your manifold have the hole that the vertical tube fits into machined into it?
Does it also have the associated pathway to the opposite side cast into it?

[Norris McCarty]

Yes it does have the machined hole and the pathway to the boss on the topside.

[51 MERC-CT]

Originally Posted by Norris McCarty

Yes it does have the machined hole and the pathway to the boss on the topside.

Then the method you plan on using rather than inside plumbing, makes sense.

[Norris McCarty]

Hey Merc!
What if I cut a 3/8” or so 1/2” deep slot between the two holes where the carb would go (which now has a block off plate)to join the left and right plenum. The left and right plenums are currently separated completely under the carbs..... this would join the plenums under the block off plate. I would then need only one vacuum fitting to run to the pcv valve?? I could just enlarge the hole/fitting to 3/8” that I currently have in my block off plate. This is all a question!

I can be dangerous and screw up a lot of parts given too much time to think!!!!!

[V8COOPMAN]

Originally Posted by Norris McCarty

I can be dangerous and screw up a lot of parts given too much time to think!!!!!

Well, me too, but here are MY thoughts anyway! First of all, WHY are 'we' using a neat old Navarro 3-carburetor manifold....with the two end positions blocked-off? None of my business, but just curious, especially if you are going to start irreversibly cutting on that web between the two bores. You could easily accomplish the same result with a little whittling on one THICK plate, or with two stacked plates, with the bottom one whittled-out over that center web.

Secondly, in my opinion (and WTF do I know), if you leave your vacuum source fitting in the position shown, that front, right cylinder is likely to do the majority of the sucking, hence......run leaner than about all of the others. Air is like real thin water.....it follows the path of least resistance. To prevent any more unbalance in the mixture than necessary, that vacuum fitting needs to be pretty much centralized in the grand scheme of things. End cylinders (especially with ONE carburetor) always tend to run leaner as it is. I BELIEVE you'd be better off designing a plate (spacer, maybe) to go under that center carb, configured such that it draws from the center of both plenums equally. That's the best 'mix' you're going to accomplish as far as even distribution of what amounts to a tiny vacuum leak. But again, what do I know? DD

PS......Don't forget (if you read my thread on our PCV project) that MOST PCV valves are designed to operate in a vertical orientation..........just sayin'!

[Norris McCarty]

I’m running the two end carbs....center is blocked off. It runs much better running the two end carbs directly connected to each other than with 3 running progressive. I can, at this point easily add the center with a block off under it for looks, but I’m try to get the car sorted out so looks ain’t my thing at the moment. It runs great like it currently is. I was working on AFR tuning then realized with the weather change, this would be a good time to work inside the shop on the needed PCV system that than trying to tune which requires driving.
I cannot run a taller spacer/block off in the center section and still adjust the rear carb. Well, I could still adjust it, but I’d have to use needle nose pliers from the side like I did when I had the three carbs on it. I have every type carb adjuster made, and home made, but that’s not a huge deal.
My whole reason for the above question was to see if I could just run one fitting on the one side of the top of the carb block off plate instead of two if I joined the right and left manifold plenums. I know that because the plenums are separated left and right I need either a common plenum or two separate vacuum fitting to pull from the PCV valve so I don’t lean out some cylinders.
Obviously not a good idea to cut a slot to join plenums....I’ll just run two, one on either side on top of the block off plate. If it works well, I may put fittings in the side of the manifold.
I have plans to run a near vertical PCV valve off of the road draft tube hole in the front of the manifold.

I really appreciate your opinions.

[51 MERC-CT]

My 4bbl. carb with PCV port has a 'Y' type groove to connect the ports.
The grooves are appox. the same width as show and half as deep.

[V8COOPMAN]

Originally Posted by Norris McCarty

I’m running the two end carbs.
I really appreciate your opinions.

Ah....Now I understand! I think you have it well under control. That is a very pleasant looking engine compartment. So happens we also have a '40 coupe. DD

[Norris McCarty]

Thanks Merc! I’ve seen those before! I think I can easily perform that minor surgery on my Navarro.
Thanks so much for your assistance!
Maybe with that modification I can run one vacuum fitting without leaning out some cylinders.
Gonna give it a shot.
Thanks again my friend

[Norris McCarty]

Once I find out how well it works, I’ll change the rubber line to copper.
I should have the tube that goes under the manifold by the weekend.
Thanks for everyone’s help.
Norris

Then I’ll get back to wideband tuning as the weather permits.

[51 MERC-CT]

The setup looks like it will work well.
The only thing that may be an issue is the positioning of the valve.
All the ones I am familiar with are meant to be mounted vertically not horizontally.

[Norris McCarty]

This particular valve is a Borg Warner PV255. It is built to use horizontally. Same valve that’s used on the road draft tube of a mid-late 60s SBC. 1/4” pipe thread on block end.
Hope it works well. At least the flow is in the correct direction! They are a bit hard to find.

[51 MERC-CT]

That's great, you are well on your way to eliminating crankcase emissions and improving the atmosphere

[V8COOPMAN]

.

How do you add oil to that critter? And where's the air intake for the crankcase? You must have an electric fuel pump, huh? DD

[Norris McCarty]

Yep, electric pump. Air and oil in via the rear breather/“fuel pump” stand.

[Norris McCarty]

Finished the pcv valve install last night.
Installed the tube beneath the manifold. Drilled and tapped the manifold at the road draft tube location and the carb block off plate for 1/4” pipe thread brass fittings. I’m using 3/8” emissions hose currently but will go 3/8” copper line as the final setup. I tried 5 different pcv valves settling on the Borg Warner PV255. This was more about “operation” than fit.
I set it up first with clear 3/8” line so I could see the “flow” of the very light oil mist as it moved from the block to the intake manifold with the different valves. The PV255 flowed the best at low vacuum RPMs and didn’t “leak” vacuum at idle or light cruise RPMs. I had a vacuum gauge setup along with my wideband gauge to keep track of lean/rich situations.
The PV255 valve worked best in a vertical position. I believe this is the best valve for a hot rod flathead....it is at least of the 5 different valves I tested.
I’m extremely pleased with the results. Drove the car almost 40 miles at 65-75mph this morning. Pulled into my shop and didn’t have a single drop of oil even begin to form on or around the oil pan or dipstick. Previous to this mod there would have most certainly been a drop or two at least form.

It’s extremely important to make sure that if using a performance manifold with separated plenums to join the plenums in some manner. Thanks to Merc’s suggestion I was able to do this in the least invasive way. Thanks Merc!


Thank all of your for your help with this little project!

[V8COOPMAN]

.

What I figured-out during our project and in my original research on the subject is that your PCV valve selection needs to mimic the approximate cubic inches (displacement) and paying attention to the parameters of a performance camshaft. Performance cams usually allow LESS vacuum than a stock cam. We ended-up selecting a PCV valve for a 302 cu. in. (original Z28) Chevy which obviously has a performance cam, in view of the fact that Heard's new flathead is 284 cu. in. (fairly close) with a performance cam. For sure, we wanted to utilize one of those small, GM-type metal PCV valves. DD

[Norris McCarty]

Yep....all of the ones I tried are for engines with displacements very similar to my flathead. The one I settled on is for a 283 SBC.

[V8COOPMAN]

Originally Posted by Norris McCarty

Yep....all of the ones I tried are for engines with displacements very similar to my flathead. The one I settled on is for a 283 SBC.

But like I said, you ought to factor-in the vacuum characteristics produced by your cam. I can't think of any 'late', factory-performance 283s with a cam....that had a factory PCV valve. DD

[Norris McCarty]

All I know is that it works. The Max1 is not a radical cam.
There may be a valve that “fits” better, but I’m pleased.
If you know of a better pcv valve for my engine, give me a part # please..... I’ll try it!

[V8COOPMAN]

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Originally Posted by Norris McCarty

All I know is that it works. The Max1 is not a radical cam.
There may be a valve that “fits” better, but I’m pleased.
If you know of a better pcv valve for my engine, give me a part # please..... I’ll try it!

YOU're happy, and that's what counts! I was just trying to keep folks who are interested in doing something like this aware of SOME of the details to consider. YWB

[51 MERC-CT]

Originally Posted by Norris McCarty

Finished the pcv valve install last night.
Installed the tube beneath the manifold. Drilled and tapped the manifold at the road draft tube location and the carb block off plate for 1/4” pipe thread brass fittings. I’m using 3/8” emissions hose currently but will go 3/8” copper line as the final setup. I tried 5 different pcv valves settling on the Borg Warner PV255. This was more about “operation” than fit.
I set it up first with clear 3/8” line so I could see the “flow” of the very light oil mist as it moved from the block to the intake manifold with the different valves. The PV255 flowed the best at low vacuum RPMs and didn’t “leak” vacuum at idle or light cruise RPMs. I had a vacuum gauge setup along with my wideband gauge to keep track of lean/rich situations.
The PV255 valve worked best in a vertical position. I believe this is the best valve for a hot rod flathead....it is at least of the 5 different valves I tested.
I’m extremely pleased with the results. Drove the car almost 40 miles at 65-75mph this morning. Pulled into my shop and didn’t have a single drop of oil even begin to form on or around the oil pan or dipstick. Previous to this mod there would have most certainly been a drop or two at least form.

It’s extremely important to make sure that if using a performance manifold with separated plenums to join the plenums in some manner. Thanks to Merc’s suggestion I was able to do this in the least invasive way. Thanks Merc!


Thank all of your for your help with this little project!

Ya' that's an advantage I noticed after installing my system.
Had a small leak at the front crank seal before and virtually none after installation.

[msstring]

Could you please post the part number for the 283 PCV valve? I would like one that has the 90 degree elbow on the top but can work around that if needed.

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[cadillac512]

Originally Posted by msstring

Could you please post the part number for the 283 PCV valve? I would like one that has the 90 degree elbow on the top but can work around that if needed.

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Quote:



"I tried 5 different pcv valves settling on the Borg Warner PV255."



Terry

[msstring]

Originally Posted by cadillac512

Quote:



"I tried 5 different pcv valves settling on the Borg Warner PV255."



Terry

Thanks!

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[Norris McCarty]

Originally Posted by msstring

Could you please post the part number for the 283 PCV valve? I would like one that has the 90 degree elbow on the top but can work around that if needed.

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The 90 degree elbow was off of the “help” rack at Oreillys

[1 Raggedy Ride]

Norris, Check with Tom Stewart, of Flat Head Sales, Riga N.Y. ... He is my local flat head engine guy, who has been doing engines for close to 50 years... His number is 585-293-3203... He doesn't throw much out, so I think you have a good chance, for getting your needed tube...
.....Lou.....