new intake ON!

[Tom Bryant]

With no plenum to use for a vacuum source that is a problem. Hey Herb, still have the road draft tube?

How about using the cool Moroso can and the tubes to the valve covers for the intake and then use a pan evacuation systen in the exhaust to draw out the bad? Then you have a source of clean air in and a vacuum pulling fumes out without worrying about running it through the cylinders. As long as the rings and valve guides/seals are good very little oil should be pulled out of the exhaust, if any.

Otherwise, with the individual runners and no common plenum you would either have to pick one cylinder to be the PCV vacuum or drill all 8 and make a small diameter tubing manifold that would draw through a common pcv valve plumbed into one valve cover with the fresh air entering the other.

I'm getting confused. I think I'll go out and work on something simple. :L

 

[IH2LOSE]

Herb

Dont feel bad I had to figure this stuff out on my 62 for the tri power set up.

Close off the pvc valve on your midyear and youll see the mess it makes in quick time.

Now as for no air cleaners,I think this is a mistake as its hard enough to keep a carburated motor running right. I would hate to think how those would be with some dirt in them .

 

[firstgear]

The challenge on Herb's engine is that the 60's PCV system used a fresh air intake from the air cleaner plumbed to the vent hole in the back of the block, and the "exhaust" side used the oil fill tube with a hose to a full manifold vacuum port on the base of the carb, downstream of the guts in the carb; Herb's setup has none of these, and there's no plenum to be a manifold vacuum source.

The 70's PCV system (without the block vent hole) used both valve covers, but it also needed a fresh air intake from the air cleaner into one valve cover and a PCV valve and hose from the other valve cover to the intake, neither of which exist on Herb's setup.

Almost any breather/can setup (like the plumbing arrangment from valve cover spacers mentioned) will only provide crankcase pressure relief, not ventilation; that works fine on race cars where some level of hot oil vapors coming out of breathers isn't a big deal, but for a street-driven car, the idea is to capture the hot crankcase vapors and route them back into the intake to be burned, not to mist them all over the engine compartment.

This will take some more thought...

not sure of how much difference this makes, but my motor according to the casting numbers is a 1974 350 cu in.......it has been changed to a 383 stroker.....does that make a diffrence in your thoughts John?

The comment "this will take some more thought"....please, chime in group....I need all the help I can get!!!

 

[firstgear]

With no plenum to use for a vacuum source that is a problem. Hey Herb, still have the road draft tube?

How about using the cool Moroso can and the tubes to the valve covers for the intake and then use a pan evacuation systen in the exhaust to draw out the bad? Then you have a source of clean air in and a vacuum pulling fumes out without worrying about running it through the cylinders. As long as the rings and valve guides/seals are good very little oil should be pulled out of the exhaust, if any.

Otherwise, with the individual runners and no common plenum you would either have to pick one cylinder to be the PCV vacuum or drill all 8 and make a small diameter tubing manifold that would draw through a common pcv valve plumbed into one valve cover with the fresh air entering the other.

I'm getting confused. I think I'll go out and work on something simple. :L

uh oh....now I am really confused....I need some help on this one.....

 

[JohnZ]

When I built my Grand Sport, I considered four different Weber cross-ram setups, and got quotes on each one; since the least expensive one was $8,000.00 and none had any means of oil fill, ventilation, or manifold vacuum source (that would work), and all could only use breathers for pressure relief only, I passed and went back to a single carburetor configuration.

This was the Inglese setup:

This was a different version of the Inglese setup:

This is a Moon setup:

This is with an original Grand Sport intake ($20K just for the manifold):

Here's an original Grand Sport at Nassau in 1963 (note oil fill at center):

 

[firstgear]

ok...now what?

 

[Tom Bryant]

I helped a friend build a '34 Ford back in the early '80s and it didn't have any oil fill or pvc on the 2x4 Wiand intake on a Chevy that we used. We just had push in breathers on the cast valve covers.The first time out we had oil all over the engine and firewall. Not running down all over but residue. His wife whipped up some thick knitted boots to put over the breathers; something like those foam pre-filters that they use on dirt cars. After that the engine stayed clean even on trips of several hundred miles. All he had to do was wash them occasionally.

I think that the pan evac system I mentioned above would do the job. Of course I could always start polishing this tomorrow.

 

[firstgear]

I helped a friend build a '34 Ford back in the early '80s and it didn't have any oil fill or pvc on the 2x4 Wiand intake on a Chevy that we used. We just had push in breathers on the cast valve covers.The first time out we had oil all over the engine and firewall. Not running down all over but residue. His wife whipped up some thick knitted boots to put over the breathers; something like those foam pre-filters that they use on dirt cars. After that the engine stayed clean even on trips of several hundred miles. All he had to do was wash them occasionally.

I think that the pan evac system I mentioned above would do the job. Of course I could always start polishing this tomorrow.

Tom, you are such a TEASE,.....I know that you know the ral value of that set up and that you wouldn't even trade me even up for my entire car.....such a TEASE!!!!otfl

 

[firstgear]

So it sounds to me that the real issue is just getting the valve covers to breathe and not toss oil everywhere in the engine compartment....I think I can make that happen with the valve cover spacers and such....if I need to do more than that, like pull a vaccum someplace I am going to be screwed for sure since I don't know what to do there. There is only enough vaccum for the intake up top, no extra.

Is this all I am worried about? The breathing of the valve covers? or is there more?

 

[Kid_Again]

Nothing to really add here, just following the post with interest.

Intakes that cost more than my crate motor. Oh dear.:crazy

 

[firstgear]

Nothing to really add here, just following the post with interest.

Intakes that cost more than my crate motor. Oh dear.:crazy

yeah, bring me the guys in the white jackets that can take my credit card, computer and phone away. Stuff me in a little white room with padding....I won't do any more harm.....it really is out of control...for sure!

 

[Tom Bryant]

Intakes that cost more than I have in my whole '59. oh my! :crazy

Herb, you're right. I am aware of the true value of that rare intake and carb. There just isn't room for it in my scrap iron bucket right now.

Here are the components for a typical crankcase evac system. The big thing with the tube out of the side goes on the valve cover and has an internal oil baffle. You won't be using these if you tap into the valve cover spacers but I would suggest getting valve cover oil baffles from Moroso or Summit to cover the inside hole on the spacers if you have room. I think you will from looking at my heads. The tube with the angle cut on one end welds into the front exhaust pipe at that angle and the exhaust flowing past it creates a low pressure condition inside that tube that draws from the crankcase. That's your vacume that you need.The smog pump check valves just keep the pressure from flowing up into the engine in case of a backfire or high pressure low flow condition like at idle. All you need is 2 smog pump check valves and the angle cut tubing. Then hook your AN lines to them (one in each exhaust pipe) and draw from one valve cover spacer. Then use the tank with the breather cap on the other to allow air in and for an oil fill.

Crankcase Evacuation System

This is the same basic concept as the old road draft tube on your original stock engine. Granted these would oil down the underside of your car when the rings got bad but yours will go into the exhaust and I don't think you will notice it at all. The underside of my '59 never got any oil on it and that short block is a little weak in the piston ring department.

This is all I can think of doing without using a drill on your intake which may be a waste of time if this setup is going to have very little vacuum anyway. I mentioned above about tapping into the runners for vacuum. Flip the intake over and drill into the runners below the butterflys and run tubes to a common connector at the rear of the lifter valley. Bore through the back of the block and put in a bulkhead fitting. Connect the runner tube junction to the inside of the bulkhead fitting with a short AN line to allow you to r&r the intake then connect a pcv valve to that on the outside and an AN line to your valve cover spacer. Use the tank and line into the other valve cover spacer as before and you will have an almost invisible PVC system. Of course this depends on your intake system actually making enough vacuum to draw through this system.

I'm out of ideas. Anyone else?

Tom

 

[firstgear]

Intakes that cost more than I have in my whole '59. oh my! :crazy

Herb, you're right. I am aware of the true value of that rare intake and carb. There just isn't room for it in my scrap iron bucket right now.

Here are the components for a typical crankcase evac system. The big thing with the tube out of the side goes on the valve cover and has an internal oil baffle. You won't be using these if you tap into the valve cover spacers but I would suggest getting valve cover oil baffles from Moroso or Summit to cover the inside hole on the spacers if you have room. I think you will from looking at my heads. The tube with the angle cut on one end welds into the front exhaust pipe at that angle and the exhaust flowing past it creates a low pressure condition inside that tube that draws from the crankcase. That's your vacume that you need.The smog pump check valves just keep the pressure from flowing up into the engine in case of a backfire or high pressure low flow condition like at idle. All you need is 2 smog pump check valves and the angle cut tubing. Then hook your AN lines to them (one in each exhaust pipe) and draw from one valve cover spacer. Then use the tank with the breather cap on the other to allow air in and for an oil fill.

Crankcase Evacuation System

This is the same basic concept as the old road draft tube on your original stock engine. Granted these would oil down the underside of your car when the rings got bad but yours will go into the exhaust and I don't think you will notice it at all. The underside of my '59 never got any oil on it and that short block is a little weak in the piston ring department.

This is all I can think of doing without using a drill on your intake which may be a waste of time if this setup is going to have very little vacuum anyway. I mentioned above about tapping into the runners for vacuum. Flip the intake over and drill into the runners below the butterflys and run tubes to a common connector at the rear of the lifter valley. Bore through the back of the block and put in a bulkhead fitting. Connect the runner tube junction to the inside of the bulkhead fitting with a short AN line to allow you to r&r the intake then connect a pcv valve to that on the outside and an AN line to your valve cover spacer. Use the tank and line into the other valve cover spacer as before and you will have an almost invisible PVC system. Of course this depends on your intake system actually making enough vacuum to draw through this system.

I'm out of ideas. Anyone else?

Tom

Tom, you are the man....I will check this over....and get back to you...Herb

 

[Muttley]

Herb:

I have no original thoughts on this, but I'm recalling an article in the Corvette Restorer a couple of years ago by Duke Williams called "Crankcase Ventilation 101". It addressed different requirements for an EFI engine vs. a carbureted one. Do you happen to have the Restorer archive CD? If not, I'll see if I can dig up the article.

-David

 

[firstgear]

Herb:

I have no original thoughts on this, but I'm recalling an article in the Corvette Restorer a couple of years ago by Duke Williams called "Crankcase Ventilation 101". It addressed different requirements for an EFI engine vs. a carbureted one. Do you happen to have the Restorer archive CD? If not, I'll see if I can dig up the article.

-David

No, sorry I don't. If you can dig it up or someone else, that might help me better with this....

thanks, Herb

 

[Muttley]

Here it is (actually found it posted by Duke on the other forum, so hopefully I'm not violating any copyright laws). You may want to contact him off line--don't think he posts here--about your particluar setup.


Crankcase Ventilation 101
By Duke Williams

A question to the online NCRS Discussion Board about vented versus non-vented oil filler caps
on mechanical lifter ‘62 Corvettes indicated that there may be some misunderstanding about
crankcase ventilation requirements, and I think this somewhat arcane piece of automotive
technology is important for enthusiasts to understand.

Let’s begin by going back to the prewar period. This was before motor oils had decent detergent
and dispersant additives and sludging was a major problem in both automotive and aircraft
engines. Research eventually indicated that blowby gas (which is primarily unburned fuel/air
mixture, not exhaust gas) was a primary cause because the heavy fraction of the unburned fuel
could condense in the crankcase, accelerating sludge formation. This led to engineering efforts to
purge blowby gas quickly before it had time to condense, and one method was to sweep the
crankcase with a continuous supply of fresh air. Thus was born the road draft tube to (hopefully)
use the slight vacuum generated by the moving air stream to draw fresh air into the crankcase
from a remote inlet, usually a vented oil fill cap.

In the mid-fifties GM’s own research indicted automotive hydrocarbon (HC) emissions as a major
cause of photochemical smog, and it was also known that up to 30 percent of automotive HC
emissions originated from expelled crankcase vapors. Thus, first in California (1961 model year)
and nationwide in 1963, authorities required closed crankcase ventilation systems where the
crankcase vapor was drawn back into the engine and consumed by combustion. These systems
were the first engine emission controls of many to follow, but they had a positive benefit on more
than just emissions. Fuel economy was increased, and the use of manifold vacuum (which exists
even at wide open throttle) assured a pressure differential to continuously supply the crankcase
with a flow of fresh air.

One problem had to be overcome. Crankcase vapors are flammable, and a carburetor backfire
(not uncommon) can propagate wherever there is a combustible mixture, so closed crankcase
ventilation systems had to incorporate an anti-backflow device to prevent potential crankcase
explosions, and it was relatively simple to incorporate this feature into a metering valve. So for
the first time ever, a controlled quantity of fresh air could be flushed through the engine to
effectively scavenge blowby gas from the crankcase, and the term positive crankcase ventilation
or PCV was born.

The basic architecture soon became cast in concrete. PCV systems were typically designed to
draw filtered air from the air cleaner, circulate it through the crankcase, and then to a manifold
vacuum source, usually at the base of the carburetor with the ubiquitous PCV valve somewhere
between the crankcase outlet and vacuum source. This architecture prevailed for years, even well
into the electronic fuel injection era; however, at some point a bright, probably young, engineer
thought: With fuel injection, there is no combustible mixture above the injectors so why do we
need an anti-backflow device? Further, he surmised that modern oil additives, higher operating
temperatures, and tight, low blowby engines of the modern era really don’t need to have the
crankcase scavenged, so why do we need all this extra hardware? Thus was born the simple
expedient of merely venting the crankcase to the throttle body (upstream of the butterfly, perhaps
with a small orifice to the downside). Rather than using manifold vacuum, an inch or two of
water pressure buildup in the crankcase is enough to force the blowby gas out, but not enough to
damage gaskets or affect power and economy. Modern motor oil additives have made sludging a
thing of the past, and there is always a slight vacuum downstream of the air filter, which assures a
continuous pressure differential while the engine is operating to keep the blowby flowing one way
from the crankcase into the intake air tract. As typically implemented, these modern systems have
a simple liquid vapor separator in the cam cover and a hose routed to a convenient place in the
inlet plumbing downstream of the air filter.

The nameless engineer who developed this new crankcase ventilation philosophy and architecture
saved the automotive industry millions, but probably didn’t receive more than his regular salary.
Not all manufacturers have adopted this new simple architecture. All I can say about this is the
answer given by a grizzled “old major”, recently returned from a tour in Viet Nam flying AC-47
“Puff the Magic Dragon” gunships, to an iconoclastic young lieutenant: “Williams, traditions die
hard!” So to answer the question: Does a crankcase ventilation system need a fresh air inlet?
No, not in the present age [of EFI systems], but it depends on the epoch of your system design. If it was designed
in the fifties, sixties, or seventies [for a carbureted engine], prevailing engineering philosophy said yes. By the late eighties [with EFI systems]
the answer was no, why bother, why spend the money?

Going back to the original Discussion Board question about Chevrolet replacing the breather oil
filler cap on 1962 mechanical lifter engines with a sealed cap to placate customers who
complained of oil misting in the engine compartment - it probably wasn’t the most elegant
solution, but the customers stopped complaining, and engines usually didn’t sludge up until long
after the warranty expired.

Duke Williams
1720 Goodman Avenue
Redondo Beach, CA 90278-2721
(310) 372-5527
dukewilliams@netzero.net.

 

[firstgear]

Here it is (actually found it posted by Duke on the other forum, so hopefully I'm not violating any copyright laws). You may want to contact him off line--don't think he posts here--about your particluar setup.


Crankcase Ventilation 101
By Duke Williams

A question to the online NCRS Discussion Board about vented versus non-vented oil filler caps
on mechanical lifter ‘62 Corvettes indicated that there may be some misunderstanding about
crankcase ventilation requirements, and I think this somewhat arcane piece of automotive
technology is important for enthusiasts to understand.

Let’s begin by going back to the prewar period. This was before motor oils had decent detergent
and dispersant additives and sludging was a major problem in both automotive and aircraft
engines. Research eventually indicated that blowby gas (which is primarily unburned fuel/air
mixture, not exhaust gas) was a primary cause because the heavy fraction of the unburned fuel
could condense in the crankcase, accelerating sludge formation. This led to engineering efforts to
purge blowby gas quickly before it had time to condense, and one method was to sweep the
crankcase with a continuous supply of fresh air. Thus was born the road draft tube to (hopefully)
use the slight vacuum generated by the moving air stream to draw fresh air into the crankcase
from a remote inlet, usually a vented oil fill cap.

In the mid-fifties GM’s own research indicted automotive hydrocarbon (HC) emissions as a major
cause of photochemical smog, and it was also known that up to 30 percent of automotive HC
emissions originated from expelled crankcase vapors. Thus, first in California (1961 model year)
and nationwide in 1963, authorities required closed crankcase ventilation systems where the
crankcase vapor was drawn back into the engine and consumed by combustion. These systems
were the first engine emission controls of many to follow, but they had a positive benefit on more
than just emissions. Fuel economy was increased, and the use of manifold vacuum (which exists
even at wide open throttle) assured a pressure differential to continuously supply the crankcase
with a flow of fresh air.

One problem had to be overcome. Crankcase vapors are flammable, and a carburetor backfire
(not uncommon) can propagate wherever there is a combustible mixture, so closed crankcase
ventilation systems had to incorporate an anti-backflow device to prevent potential crankcase
explosions, and it was relatively simple to incorporate this feature into a metering valve. So for
the first time ever, a controlled quantity of fresh air could be flushed through the engine to
effectively scavenge blowby gas from the crankcase, and the term positive crankcase ventilation
or PCV was born.

The basic architecture soon became cast in concrete. PCV systems were typically designed to
draw filtered air from the air cleaner, circulate it through the crankcase, and then to a manifold
vacuum source, usually at the base of the carburetor with the ubiquitous PCV valve somewhere
between the crankcase outlet and vacuum source. This architecture prevailed for years, even well
into the electronic fuel injection era; however, at some point a bright, probably young, engineer
thought: With fuel injection, there is no combustible mixture above the injectors so why do we
need an anti-backflow device? Further, he surmised that modern oil additives, higher operating
temperatures, and tight, low blowby engines of the modern era really don’t need to have the
crankcase scavenged, so why do we need all this extra hardware? Thus was born the simple
expedient of merely venting the crankcase to the throttle body (upstream of the butterfly, perhaps
with a small orifice to the downside). Rather than using manifold vacuum, an inch or two of
water pressure buildup in the crankcase is enough to force the blowby gas out, but not enough to
damage gaskets or affect power and economy. Modern motor oil additives have made sludging a
thing of the past, and there is always a slight vacuum downstream of the air filter, which assures a
continuous pressure differential while the engine is operating to keep the blowby flowing one way
from the crankcase into the intake air tract. As typically implemented, these modern systems have
a simple liquid vapor separator in the cam cover and a hose routed to a convenient place in the
inlet plumbing downstream of the air filter.

The nameless engineer who developed this new crankcase ventilation philosophy and architecture
saved the automotive industry millions, but probably didn’t receive more than his regular salary.
Not all manufacturers have adopted this new simple architecture. All I can say about this is the
answer given by a grizzled “old major”, recently returned from a tour in Viet Nam flying AC-47
“Puff the Magic Dragon” gunships, to an iconoclastic young lieutenant: “Williams, traditions die
hard!” So to answer the question: Does a crankcase ventilation system need a fresh air inlet?
No, not in the present age [of EFI systems], but it depends on the epoch of your system design. If it was designed
in the fifties, sixties, or seventies [for a carbureted engine], prevailing engineering philosophy said yes. By the late eighties [with EFI systems]
the answer was no, why bother, why spend the money?

Going back to the original Discussion Board question about Chevrolet replacing the breather oil
filler cap on 1962 mechanical lifter engines with a sealed cap to placate customers who
complained of oil misting in the engine compartment - it probably wasn’t the most elegant
solution, but the customers stopped complaining, and engines usually didn’t sludge up until long
after the warranty expired.

Duke Williams
1720 Goodman Avenue
Redondo Beach, CA 90278-2721
(310) 372-5527
dukewilliams@netzero.net.

thank you!!!

 

[Tom Bryant]

So, If I'm reading this right and scavenging isn't necessary on an EFI engine, and all that's necesssary is a simple vent to the air cleaner (or other outside source since there is no air cleaner) and that normal crankcase pressures are enough to expel vaprors, then the valve cover lines (with oil baffles on the inside of the vc spacers) to the fill tank should be enough to do the job. You would still need to do the fitting and valve on the bottom of the tank to allow for oil fills.

Now if you later add air filters, like 1 long oval air filter per side, then you could use one of the tanks with 2 inlets and a sealed cap. Then run the second hose to the air cleaner base to get a slight pressure differential.