Adding PCV valve to 1962 Lesabre

[62Lesabre]

Looking at curbing some blowby and adding a PCV valve system to my 401CID 62 Lesabre. I have a breather on both valve covers. Can I put a grommet in place of one and run a PCV valve with a rubber hose to the intake? Anyone done anything like this before? What do I do about the draft tube?

[rocketraider]

That should work fine. You want the fresh air intake on opposite valve cover from PCV so the PCV will scavenge the whole crankcase.

 

I don't know where the draft tube connects to crankcase on a Nailhead. If it can be unbolted, I'd clean and degrease the opening and use a rubber expansion plug to close it and defeat the draft tube.

[Bloo]

You need an inlet of clean air (a breather cap will work) and a PCV valve in some other location, so the approach with 2 breather caps you propose will be fine. As @rocketraider says you have to plug the draft tube, otherwise you will suck dirt in.

 

Not just any vacuum port will work. Well, technically it will make the PCV work, but it will make the engine run bad by screwing the fuel distribution all up. You need a carburetor with a dedicated PCV port, or you need some kind of adapter plate to go under the carburetor.

 

The PCV air needs to mix with the air/fuel coming through the carburetor. Look at 1960s Fords for ideas about how to make the adapter plate, as they used a separate one. Look at carbs with a factory PCV port to see how they located the ports. PCV should be on the primary bores (I assume it is a four barrel). Ford dumped it over by the throttle shafts, although I think right under the idle jets is probably more desirable. Avoid any sharp bends in your passages as anything associated with PCV tends to plug up with carbon. Pick a PCV valve for an engine of similar displacement and RPM range.

 

Edited October 25, 2022 by Bloo (see edit history)

[JohnD1956]

I think the main consideration is the desire to curb blowby. A pcv system will mask blowby at best, not curb it. 

[62Lesabre]

2 hours ago, JohnD1956 said:

I think the main consideration is the desire to curb blowby. A pcv system will mask blowby at best, not curb it. 

Correct. Curb blow by coming out of the engine. I understand the correction for the blow by is a $10,000 engine rebuild. There’s a difference 

[Bloo]

I would question how much it will help. There is only so much PCV air an engine will tolerate. It is never enough to ventilate the engine 100% of the time, even when the engine is new. PCV systems do ventilate better than most draft tube systems (although there are exceptions).

 

Even with a new engine, the PCV system will blow backwards through the PCV intake (the breather cap in your scenario), and get oil mist on the engine part of the time. It just gets worse as the engine wears and gets more blowby.

 

In the 1970s, they put the PCV intake filter up in the air filter housing instead of the breather cap. Then it just blew the oil mist all over the air cleaner element. That made the air cleaner element clog faster. To be fair, it did a better job of containing and re-burning blowby smoke and oil mist than plain PCV with a breather cap because the fumes got sucked into the carburetor. The plumbing for that system still tended to harbor oil and drip it on top of the engine.

 

[JohnD1956]

If it was me I'd look up how it was done with 65 parts. Those will likely fit the 62 401 and if I recall correctly it had the pcv valve in the passenger side valve cover.  Could probably adapt the 65 valley cover, and manifold. But the gas pedal linkage may be different than the 62 because the 65 had the Super Turbine 400 trans. 

[EmTee]

12 hours ago, Bloo said:

In the 1970s, they put the PCV intake filter up in the air filter housing instead of the breather cap. Then it just blew the oil mist all over the air cleaner element. That made the air cleaner element clog faster. To be fair, it did a better job of containing and re-burning blowby smoke and oil mist than plain PCV with a breather cap because the fumes got sucked into the carburetor.

If discharge from the road draft tube is the primary issue, you could try fabricating something to re-route that to the air cleaner, as described above.  You would need to either modify the air cleaner housing (or modify a 'donor').  Another option might be a collar like those used on '70s GM trucks that sat between the carburetor and the air cleaner.

 

http://67-72chevytrucks.com/vboard/showthread.php?t=645971

 

 

Edited October 26, 2022 by EmTee (see edit history)

[old-tank]

Blowby?  Remove an oil filler/breather and rev the engine.  There will be a blast of smoke from worn or broken piston rings if blowby.  If just stinky vapors from volatiles and water dissolved in the oil, change the oil and take the car out for a 100 mile run at freeway speeds.  If you do have blowby and channel those fumes to the intake to be burned, some will deposit on the back of the intake valves and give performance and driveability issues.

[drhach]

I bought this form Centerville Auto. It goes in toe valley pan where the original vent is now. I don't know what carb you have. I converted to a Q-Jet, so there was already and port for PCV. As others have said, you probably could route to the valve covers easy enough. 

 

 

 

 

53-62 PCV kits | Centerville Auto Rep (nailheadbuick.com)

[KAD36]

I had rigged one up for my 55 several years ago, ran it for a few seasons and it definitely “curbed” the issue and kept the engine bay cleaner.  It wasn’t optimal but it worked.  Before that, I used to just keep an old sock over the breather on the oil filler to try to keep the oily vapors from blowing back over the engine and prevent it from collecting dirt.

 

Finally, made the headfirst dive into that expensive option and *woo hoo* no more junk coming out of the breather tube….🤣

[drhach]

It keeps also keeps the garage from getting stinky. 

[62Lesabre]

1 hour ago, drhach said:

It keeps also keeps the garage from getting stinky. 

Yes, i think ill go the route you did with Centerville. Did you keep your road draft tube in place?

[drhach]

On 10/31/2022 at 11:35 AM, 62Lesabre said:

Yes, i think ill go the route you did with Centerville. Did you keep your road draft tube in place?

No, that's where the PCV goes. The grommet is the size of the draft tube in the valley pan. From there, I routed the base to the base of the carb. 

[joseph demeyer]

Interesting topic i am considering for my 1960 buick lesabre nailhead. Can you drill a hole in the VALLEY PAN near the carb, insert a grommet that fits the pcv and lead from there  a hose attached to the airfilter near the carb opening for the vacuum; and finally close off the breather tube at its end opening. But indeed what about the deposits on the intake valves ? Presently that breather tube is smoking heavily when idling. I dont want to clean its "filter" as it means removing the intake manifold as the only means to remove the valley cover with access to that filter. Is there any other way of cleaning that filter ( if its even necessary to decrease the smoking) or could the excessive smoking be caused by a broken piston ring (letting exhaust smoke escape into the crankcase) The engine actually runs pretty fine but maybe a compression test can give answers. I just like to run a clean engine and burn the oil fumes and any residual gas vapors - as the PCV was introduced for.

 

 

 

 

[edinmass]

A PCV valve is a controlled vacuum leak. Installing one will drastically affect carburetion. It could also affect vacuum advance on a distributor. Drain the oil overnight on a hot engine. Install a 100% synthetic motor oil. It’ll probably cut the smoking in half. Klots makes a 100 percent synthetic that DOES NOT SMOKE……..it’s about 45 bucks a quart. Dirty used car dealers use it to run cars through the auction. 

[joseph demeyer]

thanks and I agree: the least intrusive modification is often the best ! so you believe in synthetics even in antique cars....you have quite a resume ! 

[60FlatTop]

I think their are two common causes of road draft tube smoke puffers.

 

1. Valve jobs done on worn engines. It is easy to pull the heads and do a quick valve job, not so easy to rebuild the lower end. And quite a bit more involved and costly. "Tightening up" the top end when the whole engine is worn equally usually increases the blow by past the rings. Crankcase pressure will increase and the added products of combustion have to vent somewhere.

 

2. Many 50-70 year old cars have spent extended periods of time sitting after appreciable engine wear has occurred. Carboned piston rings set in various diameters of the taper worn cylinders. Some at the top where the rings are expanded, some lower where the wear is less and the rings more compressed. Cylinders with open valves can build up a coat of rust or scale with temperature changes and condensation. Even with a cautious, well lubricated start on recommissioning the rings can stay stuck in the ring lands on half of the cylinders resulting in low compression and blow by. The rust scale, even the fine stuff can cause uneven wear to the rings. Sometimes the rings will free up in a couple hundred miles of driving. I wouldn't bet on it.

[old-tank]

On 11/3/2022 at 8:58 AM, edinmass said:

A PCV valve is a controlled vacuum leak. Installing one will drastically affect carburetion. It could also affect vacuum advance on a distributor. Drain the oil overnight on a hot engine. Install a 100% synthetic motor oil. It’ll probably cut the smoking in half. Klots makes a 100 percent synthetic that DOES NOT SMOKE……..it’s about 45 bucks a quart. Dirty used car dealers use it to run cars through the auction. 

This may be the best solution.  Waaaay back the family had a well worn 51 Plymouth.  It used so much oil that it was switched from the 'expensive' Quaker State to a generic from Western Auto..  That things stunk so bad that the windows had to be open even in winter.

[NTX5467]

Yes, a pcv valve is a controlled vac leak, but also one that can be compensated for by a minor fuel curve alteration, I suspect.  NO/minimal pcv at WOT, though.  Which would mean that part-throttle would be the main area of fuel curve recalibration, which might also relate to the distributor vac advance amounts?  Which could mean the sizing of the various idle air bleeds and such in the carb venturi cluster, mainly.

 

In a worn engine, if you make one area "seal better" (as in a valve job), it CAN cause more blow-by into the crankcase, but as long as the compression rings are good, that "extra" can be minimized.  BUT, as my late machine shop operative also noted, the reason for using a deck plate to do the final honing of cylinder walls is to duplicate the forces placed on the cyl walls' "circle" by the head bolts, rather than a normal hone job and then installing the cyl heads.  During the break-in period, those stress risers can be worn down and all will be good . . . until the cyl head is removed and re-installed again.

 

In actuality, it seems that many of these things can be a bit over-blown in importance, from what I've seen.

 

Generally, in doing a valve job, all that is fixed is the ONE valve, rather than doing all of the guides, new valve stem seals, and such.  Or installing new valves where needed in order to "renew" things for another 100K miles.  On the top-side of things, letting other things "be as they may" until they become unbearable and need attention.  THEN pulling the crank/pistons out and replacing the rings ane bearings.

 

OR you go "full-tint gonzo" and do a complete overhaul/renew for ONE burnt valve!

 

As I have posted before, adding a PCV valve set-up to an engine which did not have one, just replicate what Chevy had in 1965.  A sheet metal "cap" that goes where the road draft tube did, a screw-in brass fitting for the back of the carb, into which a screw-in pcv valve was installed, then a length of rubber hose between the valve and the metal cap.  DONE.  Readjust hot base idle mixture and, might, upsize the primary main jets ONE size to compensate for the greater air flow and ethanol'd fuels, for good measure.

 

Might use a generic pcv valve which goes "inline" in the rubber tube and use an existing intake manifold vac port on the carb?  Might also get a late-model new replacement carb which would already have the pcv hose fitting?

 

NTX5467

[edinmass]

Problem is a PCV is a HUGE leak………and it may not be that easy to correct the carburetor. It would require a five gas exhaust analyzer. A heavy straight 40 synthetic is probably the best and easiest choice. Also, figure in the mileage……most cars see very little. 

[60FlatTop]

I just came in for a break from shuffling things around in the garage to position a stuck engine job so I can pull it and rebuild the engine over the winter. All I want to do at this point is rotate the engine enough to access all three torque converter bolts.

 

Here is an idea. Maybe I will try it when I open my car lot: "Generally Honest Bernie's Used Cars".

 

Cap the road draft tube an braze a 1/4" barb connector to the plug. Run a 1/4" hose to the inlet side of the choke stove tube. Then you have a constant metered port drawing through the choke housing. The flow capacity will vary with manifold vacuum and you may have just enough to curb the blow by and do it through an existing metered port without disturbing the air/fuel balance. Certainly not an over-blown action and it might be just enough to take the curse off.

[joseph demeyer]

This is turning into a rather interesting technical discussion but I am not willing to compromise the original engine configuration of my black beauty for the sake of experimentation. Instead of Klotz (not with an s..) oil, has anyone experience with NonSmokeOil (synthetic) ? 

[NTX5467]

Not to sound flaky, but I'm seeing signals that you might need to be researching a quality engine rebuilder rather than costly fluids that might be more of a band-aid fix?  Short-term fluids might help, but I determined a long time ago that if you know where you might be headed, you need to make plans to get there, get things taken care of, and move on to other things.  Delays CAN happen if there might be some monetary issues in the mix, too.  Sometimes, "the planning" can take some time, from my experiences.

 

Respectfully,

NTX5467

[60FlatTop]

On 11/2/2022 at 9:22 PM, joseph demeyer said:

I dont want to clean its "filter" as it means removing the intake manifold as the only means to remove the valley cover with access to that filter.

And not willing to compromise the engine.

 

Those are the things that trigger strings of speculative diagnostics. Maybe even a tongue in cheek comment or two.

 

Return to go. Do not collect $200. Bring the leakdown tester.

[EmTee]

Was the car sitting in storage for an extended period before you owned it, or has it been driven fairly consistently over the years?  As far as you know, has it ever overheated badly on one or more occasions?  Either of those events can cause the rings to stick or loose their elasticity.  If stuck, you may try an oil additive such as Rislone, or others in an attempt to dissolve the carbon.  If it's smoking that badly, chances are you're not going to be able to stop it without taking it apart.

 

The original 265 in my '56 Chevy smoked profusely out of the road draft tube (~70 Kmi).  It had sat for at least 10 years before I received it from my grandparents for my 15th birthday.  Of course, I was anxious to get it running and took it apart.  I removed the heads and my father had them reconditioned.  I think that definitely increased the blow-by.  My father also stated that he believed it had overheated pretty badly at some point in its past.  Ultimately I wound up replacing the engine with a lower mileage 283, then later a 327.

[KAD36]

14 hours ago, joseph demeyer said:

This is turning into a rather interesting technical discussion but I am not willing to compromise the original engine configuration of my black beauty for the sake of experimentation. Instead of Klotz (not with an s..) oil, has anyone experience with NonSmokeOil (synthetic) ? 

I sounds like there isn’t any level of modifications that would satisfy reducing the blow by while preserving the importance of keeping the engines originality/integrity?
 

No experience here with synthetics.

 

FWIW  none of the over the counter stop smoke additives ever worked for me and being on a low hobby budget many were tried. Adding a temporary vent path and re-burning fumes or rebuilding and replacing all equally worn parts with a full rebuild worked for me.  Same experience as EmTee with a valve job only fixed other things but not that..  
 

Interested in what you decide and how it works.

 

[joseph demeyer]

Can this nailhead run relatively smooth on six cylinders ? the reason I ask is that recently I discovered two of the sparkplug cables were wrongly connected to the distributor ! yet the transporter drove it a mile through town and I in and out of the garage without protests. But after correcting the cables I noticed indeed a calmer vibration but the heavier smoke from the breather tube: at least one of the previously non firing cylinders has a broken ring issue ? Will perform a compression test on all eight before an expensive rebuild. In the meantime I simply enjoy repairing minor issues : freeing the wiper motor-mechanically, more than the electric cat eye clock, the most complex piece on this pre-digital car ! - from  hard caked grease: perfect now, even the washer !; finally fixing the leaking raingutter along the top bottom for a dry trunk; getting all the lights to work including improvised roof and trunk ones and even an interior fader ;  repairing a mice investation damage in the front passenger seat - and eradicating the smell ! ; clearing all the body drain holes; replacing the bastardly frozen temperature switch and repairing related vacuum lines, switches and wires : let there be light on the instrument panel ! ; installing rear panel speakers for that surround sound from the new repli-radio (even though the old tube one amazingly still worked ! ); and now putting black beauty's behind on jacks to test the speedometer and fuel gauge...That's how these  past two Covid years were blissfully  overcome. Yes, will keep you posted ! (oh...did I mention I got that clock running again ?)

[RivNut]

On 10/29/2022 at 9:29 AM, drhach said:

I bought this form Centerville Auto. It goes in toe valley pan where the original vent is now. I don't know what carb you have. I converted to a Q-Jet, so there was already and port for PCV. As others have said, you probably could route to the valve covers easy enough. 

 

 

 

 

53-62 PCV kits | Centerville Auto Rep (nailheadbuick.com)

The only thing that you have to worry about with this setup is getting oil directly in the valve.  You need a baffle and some kind of screen to keep the oil out of the valve.  Some of the early Z-28 Camaros had a similar setup but they had a screw-in PCV valve.

[drhach]

Thanks for pointing that out about the baffle. 

 

As an aside, I found a guy who did a study without a baffle, and with a couple of different baffle designs. With no baffle, he calculated about a quart of oil every 600 miles through the PCV. With a couple of different baffle designs, he was able to get that down to about a quart every 30K miles. Not a perfect study, but pretty interesting. 

 

PCV Valve Baffle vs. Oil Consumption Test Study – M/E Wagner Performance Products (mewagner.com)

 

 

[Bloo]

That's a common problem with aftermarket valve covers for American V-8s of various kinds. A lot of them don't come with baffles, but do have provision for a PCV valve. The oil burning that results is often severe. It is worth considering that no matter where you put a PCV valve.

 

Edited November 14, 2022 by Bloo (see edit history)

[joseph demeyer]

The purpose of the PCV is to first of all burn off any unused fuel vapors ( if I understand correctly) I noticed that my fuel tank releases a noticeable amount of fuel vapor through its rubber hose vent tube sticking out next to the filler and fuel tank cap . It seems to go to waste. Has anyone ever connected a long hose connected to this vent tube back to the engine bay and the PCV and have the vacuum transfer this fuel vapor from the fuel tank into the carburetor for a better usage?

[Bloo]

That was a common emission control in the 1970s. A charcoal canister is usually used. I think some systems existed that did not have a canister, but if so that did not last long at all. I don't recall why but there may have been some explosions.

 

If you do this, you want a charcoal canister. The plan goes something like this: The vent hose from the gas tank goes to the canister, and as the gas expands and the vapors come out, they go through a bed of activated charcoal where they are trapped. Any air is expelled through a grille in the bottom of the canister.

 

When the car is cold, and the coolant is cold, a coolant-temperature-vacuum-switch in the coolant sends a vacuum signal to a purge control valve. Sometimes the purge control valve is mounted right on the canister. This purge control valve connects engine vacuum to a larger hose known as a "purge hose". Using the purge hose, engine vacuum sucks air backwards through the charcoal canister, sending any stored vapors back to the engine to be burned. You don't really get any good out of the fuel. It just happens when the engine is cold and running on choke. It won't mind some extra fuel.

 

Edited November 27, 2022 by Bloo (see edit history)

[joseph demeyer]

Going back to the PCV modification: does any one know where I could get a SPACER with a PCV port to put under my 2 (two) barrel Carter carburator  on my 1960 Buick Lesabre engine ?

[60FlatTop]

Summit Racing should have a 1" aluminum spacer that you could drill two passages, one to each bore, and tap for a central fitting.