Vacuum Line Question on the Intake Manifold

MICAH1 · 02-29-2004

I have read some of the post on the vacuum line connections and a couple of comments stuck out to me. The small hose from the valve cover according the the post I've read should be connected to the small vacuum port on the front of the intake manifold next to the brake booster port. I have always connected the two vacuum lines from the distributor to that small port on the intake, the other vacuum line to the port on the base of my 32/36 weber, and that smaller hose from the valve cover ...... plugged in to that "L" shaped port on the back side of the intake manifold. My GT's have always been 1973's. Are the 1968 - 1972 intake manifolds minus that "L" shape port? Is my vacuum line connections wrong?

opeldean · 02-29-2004

Originally posted by MICAH1
. I have always connected the two vacuum lines from the distributor to that small port on the intake, the other vacuum line to the port on the base of my 32/36 weber, and that smaller hose from the valve cover ...... plugged in to that "L" shaped port on the back side of the intake manifold. [/B]

Micah..i think mine is as you have described...bucky

MICAH1 · 02-29-2004

Bucky, if you pull this site you can clearly see what my post is saying. Are there two types of intake manifolds?
http://opelgt.com/photos/showphoto.p...sort/1/cat/533

oldopelguy · 02-29-2004

Actually, if I had a working digital camera, I could get you pictures of 7 or more distinctly different 1.9L manifolds all in my basement.

The thing to look for for the hose to the valve cover is which port has the tiny orifice in it to keep that line from looking like a serious vacuum leak. It changed year to year and model to model as to location, and sometimes for manual and automatic trannys as well.

opeldean · 02-29-2004

the vacuum lines were explained to me by kwilford..

here is a part of his memoirs:

kwilford · 03-01-2004

MICAH1, it sounds like you have it correct. As shown by Bucky's photo, early (I believe prior to mid '70) intake manifolds have the PCV orifice fitting on the INBOARD (engine) side of the manifold. Or is it AFTER mid '72? Whatever, I have seen both types. The main thing is to have the small hole in the valve cover connected to a "metered" orifice (about 1/16") in the intake manifold.

And the only distributor connection directly to the manifold should be the small hose (the vacuum retard, for '68 to '74 Opels), as it is used to reduce NOX at idle. The bigger hose (as correctly stated by MICAH1) is the vacuum advance, and needs to be connected to the port near the base of the carb, so that it sees a vacuum when the throttle is opened up, and advances the timing.

HTH

MICAH1 · 03-01-2004

Bucky, Oldopelguy, and Kwilford, thanks much for clarifying this issue. For a moment there, I thought that I had it wrong all these years.

Oldopelguy, when you get your hands on the digital camera I would appreciate pictures of the different types of intake manifolds. Never know when I might expand the fleet.

02-29-2004	#1 (permalink)
MICAH1 101st Airborne Vet V.N. Join Date: Jun 2003 Location: Fort Washington, Maryland Posts: 643 Real Name: Thomas Johnson	Unanswered: Vacuum Line Question on the Intake Manifold I have read some of the post on the vacuum line connections and a couple of comments stuck out to me. The small hose from the valve cover according the the post I've read should be connected to the small vacuum port on the front of the intake manifold next to the brake booster port. I have always connected the two vacuum lines from the distributor to that small port on the intake, the other vacuum line to the port on the base of my 32/36 weber, and that smaller hose from the valve cover ...... plugged in to that "L" shaped port on the back side of the intake manifold. My GT's have always been 1973's. Are the 1968 - 1972 intake manifolds minus that "L" shape port? Is my vacuum line connections wrong?

02-29-2004	#4 (permalink)
oldopelguy Have Opel, Will Travel Join Date: Mar 2002 Location: Saint Michael, MN Posts: 1,727 Logbook Entries: 3 Provided Answers: 2	lots more than 2 Actually, if I had a working digital camera, I could get you pictures of 7 or more distinctly different 1.9L manifolds all in my basement. The thing to look for for the hose to the valve cover is which port has the tiny orifice in it to keep that line from looking like a serious vacuum leak. It changed year to year and model to model as to location, and sometimes for manual and automatic trannys as well. __________________ 1958 Rekord Sedan, 1958 Olympia Wagon, 1959 Opel Olympia Sedan, 1967 Kadett Coupe, 1967 Admiral Sedan 4L CIH-6, 1968 Kadett fastback 1.1L, 1970 Kadett Wagon Turbo 2.2L, 1971 Kadett Sedan 1.1L, 1975 Manta Wagon 4.3L V-6

03-01-2004	#6 (permalink)
kwilford Über OpelGT.com Moderator Join Date: Mar 2002 Location: Calgary, Alberta, Canada Posts: 4,087 Real Name: Keith Wilford Provided Answers: 4	MICAH1, it sounds like you have it correct. As shown by Bucky's photo, early (I believe prior to mid '70) intake manifolds have the PCV orifice fitting on the INBOARD (engine) side of the manifold. Or is it AFTER mid '72? Whatever, I have seen both types. The main thing is to have the small hole in the valve cover connected to a "metered" orifice (about 1/16") in the intake manifold. And the only distributor connection directly to the manifold should be the small hose (the vacuum retard, for '68 to '74 Opels), as it is used to reduce NOX at idle. The bigger hose (as correctly stated by MICAH1) is the vacuum advance, and needs to be connected to the port near the base of the carb, so that it sees a vacuum when the throttle is opened up, and advances the timing. HTH __________________ Keith Wilford working on my '71 GT and '75 SportWagon Last edited by kwilford; 03-01-2004 at 02:05 AM.

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02-29-2004	#3 (permalink)
MICAH1 101st Airborne Vet V.N. Join Date: Jun 2003 Location: Fort Washington, Maryland Posts: 643 Real Name: Thomas Johnson	Bucky, if you pull this site you can clearly see what my post is saying. Are there two types of intake manifolds? http://opelgt.com/photos/showphoto.p...sort/1/cat/533

03-01-2004	#7 (permalink)
MICAH1 101st Airborne Vet V.N. Join Date: Jun 2003 Location: Fort Washington, Maryland Posts: 643 Real Name: Thomas Johnson	Bucky, Oldopelguy, and Kwilford, thanks much for clarifying this issue. For a moment there, I thought that I had it wrong all these years. Oldopelguy, when you get your hands on the digital camera I would appreciate pictures of the different types of intake manifolds. Never know when I might expand the fleet.

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