Inliners International Forums General Discussion Engines I'd like to discuss modifying the road draft tube.

As my coupe is right hand drive, and the road draft tube wants to sit right where the steering shaft must go, I've moved it:


Can anyone foresee any problems with this solution to this dilemma?

Eliminate completely. Install a PCV system.

Larry

I forgot to mention, I will initially run a triple carb manifold w 3 BXV2's, and it doesn't have vacuum provisions.

Later I want to run the Wade Blower I've shown the pictures of on the Forced Induction section of this Bboard.

so how does one route a PCV system in these instances, or will my modified roads draft rube provide sufficient exhausting of the engine fumes?

I have 2 Offenhauser right angled breathers I can install, but I do not want to put them onto the Nicson valve cover I have just purchased.

Make sure the end is slash cut facing the rear, or it won't suck the vapors out of the crankcase. Then you should be fine.

I was afraid you were going to ask.

By law here in California the PCV system was required on vehicles from 1952 on. A PCV system is about the only smog system that is worth while. Since it burns off fumes in the crank case.

I installed about a 1/2 dozen on 235s in 64, when I worked in a gas station. There were several approved kits for 235s. One kit blocked off the road draft tube and the other eliminated the road draft. I believe a freeze plug replaced the road draft tube. The valve cover was vented and ran to the air cleaner. The breather on the valve cover was replace with a cap. Basically you blocked off the crank case, then added a vent with a PCV to the carb. The PCV keeps a backfire from igniting the fumes in the crankcase. :rolleyes:

There were some PCV kits that used a spacer under the carb with a vacuum port. I don't remember there being a spacer for under the 1bbl with a vacuum port. They did make that spacer for 2 and 4 bbls. What I'm getting at is block off the road draft tube with a freeze plug that has a 3/8 fitting in for pipe or hose. Run the copper pipe back behind the block and to a spacer under the carb. I don't know of any place to get to the crank case under the intake. You might end up with two dummy spacers, so the linkage isn't a pain.

Then again the road draft tube looks ok. I recall that some road draft tubes were cut on an angle on the back side and low enough to catch the air under the car. I can remember cars going down the road and belching smoke out the road draft tube.

Larry

Dear Mark;

Simply use a straight piece of coper pipe/tubing from a Plumbing Store & put a breather cap on it.

Looks good, fits perfect. If there's a place for one, use a breather cap on the valve cover too. Otherwise; one on the block is enough.

Happy trails.

Hi,

On www.wixski.com you can see the pcv system I made. We are just starting our website, so this is the first part we have on it. Works on my 56.
Other stuff coming

Larry;

PCV is not required/needed "down under".

It's just extra "plumbing" that does nothing, for anything and a waste of time/money for an early vehicle, especially a Hot Rod.

It didn't come out till the 60s here (from factory) and only required on 1975 & newer vehicles in California.

A 'factory' system, in good working order is okay as mentioned.

Happy trails.

the oily residue I had all over the bottom of my 56 Chevy for 253,000 miles is now gone

John,

I thought the PCV might not be required "down under". IMHO the road draft tube on a 235 looks like a kludge.

Your right "for an early vehicle, especially a Hot Rod." is unnecessary. As mentioned the PCV system does burn the fumes in the crank case eliminating some of the build up of crud.

Your partially right again the PCV "didn't come out till the 60s here (from factory)". I worked at an approved SMOG station, the owner was certified. The PCV law in Calif. was retroactive till 1952, but only required if you were going to sell the vehicle. I've often wonder why it wasn't part of the smog check. Perhaps because it was required so early.

Larry

L;

It was the beginning of the government's over regulation of the auto industry ("smog lie") starting around 1959.**

It (PVC) was used on military vehicles to keep debris out of the crancase during WW II (to start with) allowing the engine to breath.

During the 1950s, most of the vehicles on the highway were MFG in the 30s & 40s having worn piston rings. These; when slowing down or traveling downhill, pulled oil past the rings and then smoked a lot afterward.

The PVC systems prevented this and why they were required for a while in some States.

Later; the KV system was added and still exists today. These MUST be in place to pass SMOG along with the rest of the garbage.**

Happy trails.

PS: There's a big discussion of all this (Bench Racing) listed as "BIG BROTHERS SMOG LIE".

** It's escalated to where they (SMOG devices) now cause the vehicle to use much more fuel that necessary, creating more tax revenue for the government. Plus all the BS that goes along with it, fees/controls/inspections. etc.

In California; It's the largest and most well orchestrated, 'consumer fraud' EVER created.

If 'clean air' were the issue, the electric car would NOT have been subverted, three times here, beginning in 1974.

We seem to go round and round about this topic... I did my masters thesis on gas sensors for automotive pollution control so I feel that I have some knowledge about the topic. If I had it handy, I'd give you the references to look it up yourself. The literature indicated that crankcase gases were the biggest pollution offender and a functioning PCV system is the most rudimentary pollution control device. It also indicated that the optimum fuel/ air ratio to minimize pollution (NOx, CO, and hydrocarbons) is stoichiometry. It is not part of some widespread conspiracy to consume more fuel.

Gentlemen, We continue to get further off topic.

Larry

Looks alright on the photo.
You'll just get the oil spray a few inches further towards the front.

I prefer the original road draft tube over PVC.
I like to stuff the large chamber with stainless steel wool loosely, to cut down on most of the oil spray.

PCV sucks - or should I say, it stops sucking at higher rpm driving on freeways.
In those conditions, you need a big opening (road draft tube) or a lot more suction to get rid of all the extra crankcase pressure.
The small PCV passages can't handle the pressure and you lose oil at the dip stick tube and distributor.
This makes the PCV system actually worse than the road draft tube, in terms of polution.
Even with a condensation filter, PCV clogs up the combustion chambers and intake valves gradually with crusty deposits, that rob power and can only be removed by pulling the head and scraping.

Governments in general have established traditions of passing on guilt to everyday citizens.
It's just a lot easier to get funds from them and keep them from thinking and asking questions.

If anybody really wants cleaner air, how about starting with personal sacrifices in our private consuming habits, followed by inspecting industrial factories and leave us old car and truck owners alone. We are not the problem - period.

Sorry for the off-topic comment, but PCV is about cleaner air, I was lead to believe.


One more thought...
Modern engine polution control for engines that last only for a handful of years ... :rolleyes:
Just another reason why I only ever owned my two Chevys and nothing else.
Road draft tube and all ...

Mark, regarding your second question about routing the PCV: In my '56 Chassis service manual, it shows a small tube between the road draft tube that goes up over the valve cover and back into the intake at the vacuum port that is used for wipers, etc - the one right in the center of the intake. Later on chevy connected it to the air cleaner. The road draft tube is closed so it doesnt vent into the atmosphere at all. The vapors go back to the intake.

I thought the factory method looked kind of ugly, so with the PCV cannister I made, I run a hard line around the back of the engine and connects to the intake. I have an offy dual carb manifold, so I drilled and tapped for 1/8" pipe and just put a fitting for the hard line. You relly cant see it from the manifold side because it is on the back side pointing toward the firewall. Pretty simple actually.

Tom, I agree with what you've done, and your PCV cannister looks great - I just cannot bring myself to drill a hole in vintage speed equipment

I am going to have a PVC on anything I drive even if it's a model "T". I inhaled all the "Gulf Prides" out of those old road draft tubes I want to. For you young guys that haven't heard of Gulf Pride it was a motor oil produced by Gulf Oil Co. and it stunk just as bad in the can as it did burning. SCRAPIRON

I'm with you, Scrap. I had a '56 Chevy 235. Never smelled anything on the highway, but in town I'd get that sickening odor....especially when it was hot outside. I used the pcv valve off of a military M-37 and sealed off that draft tube. engine ran the same, but no more odor in town. I drove that sucker 210,000 miles, with an in-car set of bearings, rings, valve job and gaskets at 160,000 miles. It was still running good when I sold it.

Mark, just use the hole that the mfg put in the manifold for the wipers etc in the middle of the manifold. I wanted my line hidden, thats why I drilled the other hole. The line could just as easily gone forward 9" and used the 'factory" hole.

hey, I sent an email on the jahn's pop ups. Did you get it?

Thnx Tom, I received emails from you and Jim, and have replied to Jim.

Have you got any more pictures of your set-up?

I only have one crappy picture on the website we just set up - www.wixski.com I'll take a couple more and put them on there this week. it isnt very good, but you will get the idea

we are just getting the website up and running so some better ones to follow

M;

Be careful here.

The PCV system connects to the intake manifold, NOT the air cleaner, via a 1/2" special PCV hose. This requires a 1/2" NPT opening in the intake center (for the nipple) to function properly. The valve cover then MUST use an open breather cap as well.

A copper tube & cap is under $20 and takes 10 minutes to install.

Good luck.

If you get fumes, get rid of the valve cover breather cap and connect a 3/8" ID hose to the carb filter. PCV or road draft tube - same thing.

I got this setup with my daily 235 with draft tube and never have any fumes.
My dogs drive with me everywhere inside the cab and their noses approve.

When I had PCV for a couple of years, I had to drain the condensation filter about once a week during the colder months.
About 2/3 cup of fluid each time.
Hard to believe how much moisture is inside the crankcase, just from blowby.