PCV?
Safety Car
Joined: Feb 2000
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From: Massachusetts , USA,
Re: PCV? (BluByU)
all BIG BLOCKS have PCV , the 396 being an unusual set/up in 1965 & I think for small blocks 1966 was first year / or might be 1965.............. or :confused: , you need a small block genie to answer this one.......... :seeya :flag California Vettes could have had PCV earlier.................
[Modified by StrayDog, 8:49 AM 6/12/2002]
[Modified by StrayDog, 8:50 AM 6/12/2002]
[Modified by StrayDog, 8:51 AM 6/12/2002]
[Modified by StrayDog, 8:49 AM 6/12/2002]
[Modified by StrayDog, 8:50 AM 6/12/2002]
[Modified by StrayDog, 8:51 AM 6/12/2002]
Melting Slicks
Joined: Apr 2002
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From: 20 forward gears to shift through in MD
Re: PCV? (BluByU)
I am not 100% sure, but it may have been with the introduction of the 327 in 1962. I know the old Blue Flame Six had a draft tube. Not sure about the 265 or 283's though.
Melting Slicks
Joined: Aug 2000
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From: The Garden Spot of the Garden State
Re: PCV? (BluByU)
...i have to check the references but, fwiw, my '65 sb has no pcv valve..it was originally a 350hp engine...i know that, at least, the '64 FI engine had a pcv valve
Melting Slicks
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From: 20 forward gears to shift through in MD
Re: PCV? (BluByU)
From all the references I can find on-line, all corvettes from 1963 up had PCV valves (also found that California required PCV valves on all cars in 1963 as well). Still not sure whether or not 1962 had them...
Race Director
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Re: PCV? (Denney)
PCV systems were required by federal law on all cars beginning in the 1963 model year. California required them beginning in 1961 and this requirement was covered by RPO 242.
By recirulating crankcase vapors back into the cylinders for combustion, HC emissions were reduced about 20 percent and fuel economy increased. Also, better crankcase ventilation reduced oil dilution, so the was no downside as on later exhaust emission controls.
Duke
By recirulating crankcase vapors back into the cylinders for combustion, HC emissions were reduced about 20 percent and fuel economy increased. Also, better crankcase ventilation reduced oil dilution, so the was no downside as on later exhaust emission controls.
Duke
Melting Slicks
Joined: Aug 2000
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From: The Garden Spot of the Garden State
Re: PCV? (SWCDuke)
well, the dawn is breaking over here but VERY slowly...my '65 has no PCV valve (nothing's been right OR correct on the car to begin with, so that's no surprise)..i have crankcase ventilation from the hole in the back of the block where the draft tube used to be installed to the base of the air cleaner and from the oil filler tube to an elbow in the side of the holley, right next to the throttle linkage - no PCV valve.......
..when i look at the LICS catalog (not necessarily an authoritative reference source), i see the '65 appears to have an elbow pcv (a bit like the '64 FI version) coming out the back of the carb base to the vent on the oil fill tube - is that the way it was done? :confused:
[Modified by Kid_Again, 5:34 PM 6/12/2002]
..when i look at the LICS catalog (not necessarily an authoritative reference source), i see the '65 appears to have an elbow pcv (a bit like the '64 FI version) coming out the back of the carb base to the vent on the oil fill tube - is that the way it was done? :confused:
[Modified by Kid_Again, 5:34 PM 6/12/2002]
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Melting Slicks
Joined: Oct 2001
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From: Marblehead MA
Re: PCV? (Kid_Again)
Looked at my 63 and its the same setup... no PCV valve is present.... I have a 300 HP engine with a crankcase ventilation tube from the back of the block going into the back of my carb (AFB) and a hose connection from the oil filler tube to the underside of my snorkel air cleaner... :yesnod:
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Re: PCV? (achapman)
The original question addressed "PCV systems", but not all PCV systems have valves. All 1963 Corvette engines have PCV valves. Beginning in '64 some did not have valves as part of the system.
You really have to refer to the specific year AIM to determine whether your system is properly configured. It's one of those things that Bubba tends to mess up over the years.
Duke
You really have to refer to the specific year AIM to determine whether your system is properly configured. It's one of those things that Bubba tends to mess up over the years.
Duke
Melting Slicks
Joined: Jun 2001
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From: San Clemente Ca.
Re: PCV? (BluByU)
The big deal was 1966, (at least here in Ca.)
1st year of the smog pump, then came heat tubes,
thermactors, on and on.
Thats why I have owned so many 65's.
The early attempts did little but cause problems. IMHO
Nothing to do with your question, just threw it out there. :D
"the 396 being an unusual set/up in 1965 " :confused: :confused: :confused:
Stray Dog, what was unusual? Just curious?
[Modified by 396 RAT, 10:33 PM 6/12/2002]
1st year of the smog pump, then came heat tubes,
thermactors, on and on.
Thats why I have owned so many 65's.
The early attempts did little but cause problems. IMHO
Nothing to do with your question, just threw it out there. :D
"the 396 being an unusual set/up in 1965 " :confused: :confused: :confused:
Stray Dog, what was unusual? Just curious?
[Modified by 396 RAT, 10:33 PM 6/12/2002]
Melting Slicks
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From: The Garden Spot of the Garden State
Re: PCV? (396 RAT)
...yeah, you're right duke...looked at brother noland's book last night and it has a picture of the sb holley, from the linkage side and there is clearly an elbow coming out the side, much larger that what i have and i believe that's a pcv valve
Thread Starter
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From: stop the fun suckers
Re: PCV? (Kid_Again)
i have crankcase ventilation from the hole in the back of the block where the draft tube used to be installed to the base of the air cleaner and from the oil filler tube to an elbow in the side of the holley, right next to the throttle linkage - no PCV valve.......
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Re: PCV? (achapman)
Looked at my 63 and its the same setup... no PCV valve is present.... I have a 300 HP engine with a crankcase ventilation tube from the back of the block going into the back of my carb (AFB) and a hose connection from the oil filler tube to the underside of my snorkel air cleaner... :yesnod:
Your '63 L-75 should have an AC PV 590C valve threaded into the elbow that's threaded into the bushing at the rear base of the carb. The valve is on the "passenger side". Clean air from the filter housing flows to the oil fill tube, circulates throught the crankscase and enters the throttle body. The valve is there to meter the airflow. Manifold vacuum is present downstream of the valve, so it is necessary to prevent drawing excess air and oil at high manifold vacuum.
'64 and '65 PCV SB configurations do not have a valve, including FI. Under manifold vacuum conditions clean air is drawn from the filter to the port at the back of the block and enters the manifold through a metering orifice in the carb. Under WOT conditions, flow can reverse.
GM eventually abandoned the valveless PCV systems, and I believe all '66 engine configurations have a valve. All BBs (including the L-78) use a valve and their PCV systems route between the valve covers.
Duke
[Modified by SWCDuke, 9:34 AM 6/13/2002]
Team Owner
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From: Washington Michigan
Re: PCV? (Kid_Again)
The brass elbow on the driver's side of the Holleys with the rubber hose to the oil fill tube (with no PCV valve) has an .090" orifice in it to meter the flow of blow-by gases to the carb; it's a regular tune-up maintenance item, described in the Service Manual, to use a piece of wire to ensure that the .090" orifice in the elbow is not carboned-up and blocked. If it's blocked, the system won't work.
Thread Starter
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From: stop the fun suckers
Re: PCV? (JohnZ)
The brass elbow on the driver's side of the Holleys with the rubber hose to the oil fill tube (with no PCV valve) has an .090" orifice in it to meter the flow of blow-by gases to the carb; it's a regular tune-up maintenance item, described in the Service Manual, to use a piece of wire to ensure that the .090" orifice in the elbow is not carboned-up and blocked. If it's blocked, the system won't work.
Thanks
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Re: PCV? (Kid_Again)
All I have in my 67 327 is the breather in oil cap. The oil fill tube does not have a connection for a hose to the carb. I'm intrested in knowing what I 'should' have. Mines a driver, but would like to have the motor breathing correct.
Thanks
Thanks
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Re: PCV? (67gilmore)
Is it the original case or similar early case with the hole in the back (just behind the manifold) for a crankcase vent pipe, or do you have a later case with no such provision.
It's good that people are thinking about this subject. Most amateurs and even a lot of professional engine builders pay little if any attention to crankcase ventilation, which is important for both performance and engine longevity.
Duke
It's good that people are thinking about this subject. Most amateurs and even a lot of professional engine builders pay little if any attention to crankcase ventilation, which is important for both performance and engine longevity.
Duke