 To PVC or not to PVC?, What should a 74 2.0 have? |
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| robkammer |
 Dec 8 2021, 02:10 PM
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#1
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Member  Group: Members Posts: 179 Joined: 7-January 21 From: Vermilion Ohio Member No.: 25,049 Region Association: North East States  |
I'm in process of cleaning up all of the electrical and vacuum lines in the engine bay. The car does have a check valve of sorts, maybe a PCV. I read differing accounts of whether or not a 74 should have one or should it just be plumbed without?
And I've gotta say, it sure looks nice in there without any vacuum lines! Rob |
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| 914_teener |
Dec 8 2021, 03:12 PM
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#2
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914 Guru Group: Members Posts: 5,205 Joined: 31-August 08 From: So. Cal Member No.: 9,489 Region Association: Southern California |
QUOTE(robkammer @ Dec 8 2021, 12:10 PM)  I'm in process of cleaning up all of the electrical and vacuum lines in the engine bay. The car does have a check valve of sorts, maybe a PCV. I read differing accounts of whether or not a 74 should have one or should it just be plumbed without? And I've gotta say, it sure looks nice in there without any vacuum lines! Rob You should run one IMHO. Otherwise stock up on valve cover gaskets. |
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| emerygt350 |
Dec 8 2021, 05:04 PM
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#3
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Advanced Member Group: Members Posts: 2,154 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
QUOTE(914_teener @ Dec 8 2021, 04:12 PM) QUOTE(robkammer @ Dec 8 2021, 12:10 PM) I'm in process of cleaning up all of the electrical and vacuum lines in the engine bay. The car does have a check valve of sorts, maybe a PCV. I read differing accounts of whether or not a 74 should have one or should it just be plumbed without? And I've gotta say, it sure looks nice in there without any vacuum lines! Rob You should run one IMHO. Otherwise stock up on valve cover gaskets. The 74 was a passive vent system into the air cleaner. I prefer the positive flow on my motors (like the 73) but if passive was good enough for Porsche/VW... You need it. 1) you don't want to vent that to atmosphere 2) gaskets 3) engines last longer if those gases are not in there too long. |
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| KELTY360 |
Dec 8 2021, 08:34 PM
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#4
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914 Neferati Group: Members Posts: 5,038 Joined: 31-December 05 From: Pt. Townsend, WA Member No.: 5,344 Region Association: Pacific Northwest 
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PCV not PVC
One is a valve the other is plastic pipe. |
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| JamesM |
Dec 9 2021, 03:16 AM
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#5
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Senior Member Group: Members Posts: 1,922 Joined: 6-April 06 From: Kearns, UT Member No.: 5,834 Region Association: Intermountain Region |
QUOTE(emerygt350 @ Dec 8 2021, 04:04 PM) QUOTE(914_teener @ Dec 8 2021, 04:12 PM) QUOTE(robkammer @ Dec 8 2021, 12:10 PM) I'm in process of cleaning up all of the electrical and vacuum lines in the engine bay. The car does have a check valve of sorts, maybe a PCV. I read differing accounts of whether or not a 74 should have one or should it just be plumbed without? And I've gotta say, it sure looks nice in there without any vacuum lines! Rob You should run one IMHO. Otherwise stock up on valve cover gaskets. The 74 was a passive vent system into the air cleaner. I prefer the positive flow on my motors (like the 73) but if passive was good enough for Porsche/VW... You need it. 1) you don't want to vent that to atmosphere 2) gaskets 3) engines last longer if those gases are not in there too long. Not sure exactly when the changeover was, but every 74 I have had has the PCV getting suction from the plenum. 75+ had the larger passive vent to the air cleaner. To properly remove it though you will need to swap both your plenum and airbox to later parts. I think there are pros and cons to both, the biggest con of keeping the PCV now is that new/good ones are near impossible to come by. Post pics of your plenum and I can tell you what you have. |
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| emerygt350 |
Dec 9 2021, 05:39 AM
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#6
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Advanced Member Group: Members Posts: 2,154 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
The last 74 I looked at was passive but perhaps it had been messed with.
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| robkammer |
Dec 9 2021, 08:50 AM
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#7
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Member Group: Members Posts: 179 Joined: 7-January 21 From: Vermilion Ohio Member No.: 25,049 Region Association: North East States |
Thanks guys. This isn't the best picture, looks like a valve but confirmation would be good.
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| BeatNavy |
Dec 9 2021, 09:36 AM
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#8
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region
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That little circular thing next to the oil (or "oel") filler neck is indeed a PCV valve.
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| emerygt350 |
Dec 9 2021, 11:49 AM
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#9
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Advanced Member Group: Members Posts: 2,154 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
Clean it up and plug her in....
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| JamesM |
Dec 9 2021, 08:39 PM
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#10
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Senior Member Group: Members Posts: 1,922 Joined: 6-April 06 From: Kearns, UT Member No.: 5,834 Region Association: Intermountain Region |
QUOTE(robkammer @ Dec 9 2021, 07:50 AM) Thanks guys. This isn't the best picture, looks like a valve but confirmation would be good. That is indeed an early crank case vent system/PCV valve. It looks like your intake plenum is the later style though (based on the thicker throttle cable bracket) and that presents a bit of a problem as the later style does not have the port necessary to attach the CCV to it. You can verify this by checking the two ports on the side of the plenum. The late style has a large and small port, the early style that is needed has two larger ports. Not sure what airbox you have but you will need the matching early style as well.  |
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| r_towle |
Dec 9 2021, 11:01 PM
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#11
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Custom Member Group: Members Posts: 24,594 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
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QUOTE(KELTY360 @ Dec 8 2021, 09:34 PM) PCV not PVC One is a valve the other is plastic pipe. Yes, but pvc could be pcv |
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| robkammer |
Dec 11 2021, 04:47 PM
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#12
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Member Group: Members Posts: 179 Joined: 7-January 21 From: Vermilion Ohio Member No.: 25,049 Region Association: North East States |
Dislexia is not something to laugh at. Although feel free to laugh at me! Positive Crankcase Ventilation from the 70's,
Sheesh |
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