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> 74 Distributor Vacuum Question, How many ports?
74914LE
post Jul 24 2011, 11:44 AM
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In sorting out the hoses on a 74 2.0, I discovered that the vacuum advance has
two ports coming out of it (Top Side/Bottom Side), however my intake only has
one vacuum port. It is currently hooked up with the line going to the top side
port on the distributor, and the bottom side is open. Question is, should this be
plugged, or does it need to be connected to vacuum, and if so where to hook it
up? Based on the information I was able to find, it looks like I have a early 2.0
distributor, and a later 2.0 intake. Any issue here?

Thanks!
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mgphoto
post Jul 24 2011, 12:10 PM
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QUOTE(74914LE @ Jul 24 2011, 10:44 AM) *

In sorting out the hoses on a 74 2.0, I discovered that the vacuum advance has
two ports coming out of it (Top Side/Bottom Side), however my intake only has
one vacuum port. It is currently hooked up with the line going to the top side
port on the distributor, and the bottom side is open. Question is, should this be
plugged, or does it need to be connected to vacuum, and if so where to hook it
up? Based on the information I was able to find, it looks like I have a early 2.0
distributor, and a later 2.0 intake. Any issue here?

Thanks!

Hello 74914LE,
I am having some of the same confusion, late '74 engines have only on vac connection to the intake, the Factory Service Manual states the '75 model year USA cars do not connect to the vacuum advance and only connect to the retard section of the vac unit, check my my thread listed below. I am trying to find out if I have the correct vac unit for a late '74 engine, let me know if the vac unit in the photo is the same as yours.
Good luck,
Mike

http://www.914world.com/bbs2/index.php?showtopic=136830
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74914LE
post Jul 24 2011, 12:32 PM
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My distributor has a vacuum port for both advance and retard. Is the outside one the advance? Inside retard? If that is the case, then my advance is currently hooked up to the intake.
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reharvey
post Jul 24 2011, 12:48 PM
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My all original 74 2.0 made in 10/73 has two ports on the vacuum advance and only one on the throttle body. The larger hose for the retard side is hooked up but the smaller hose from the advance has a hose on it that's not connected to anything. That's the way it can from the factory--believe it or not.
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Dave_Darling
post Jul 24 2011, 11:27 PM
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The advance, the one that does not get connected to anything, is the port on the distributor dashpot that points away from the distributor body.

--DD
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mgphoto
post Jul 25 2011, 10:24 AM
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Hello Dave,
Just to find some answers not to hijack.
Is there any 2.0 L distributor that uses a single port looks like advance only?
Attached Image

This one came with a 039 905 204 A distributor that I picked up, does not seem right, for my late GA case, retard only.
But this image from the Factory Service Manual in the 2.0L section, the dizzy shown is a single vac with the connection for advance only, generic photo?
Attached Image

Any ideas?
Mike
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Dave_Darling
post Jul 25 2011, 12:02 PM
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Unless something is drastically different about the internals of the dashpot you are showing, the fitting on that one is the advance fitting. Points away from the distributor body. I think it probably isn't original, but I definitely haven't seen everything that's out there...

--DD
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Cap'n Krusty
post Jul 25 2011, 12:06 PM
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No 4 cylinder 914 came with a single vacuum uit. All had one for the advance, one for the retard. Some engines didn't use the advance side, ALL used the retard. Note the ports on the TB are different sizes, as are the ports on the vacuum can. The hoses, when used, are of corresponding sizes.

The Cap'n
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mgphoto
post Jul 25 2011, 12:08 PM
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QUOTE(Dave_Darling @ Jul 25 2011, 11:02 AM) *

Unless something is drastically different about the internals of the dashpot you are showing, the fitting on that one is the advance fitting. Points away from the distributor body. I think it probably isn't original, but I definitely haven't seen everything that's out there...

--DD

Hey Dave,
The factory parts book lists a Calif. model distributor 039 905 204 B, any experience with that version?
Mike
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Dave_Darling
post Jul 25 2011, 03:24 PM
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Yes, but not with certainty that the vacuum unit is original. As the Cap'n said, it had two vacuum fittings on it.

--DD
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74914LE
post Jul 25 2011, 07:00 PM
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Thank you for the great feedback. There are so many variables with certain areas on our cars. To confirm, the advance port (points to drivers side), does
not get connected, and the retard(points to passager side) gets connected. Also,
the size of the port on the intake, and the port on the distributor should be of the
same size when connected?
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Dave_Darling
post Jul 25 2011, 07:03 PM
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yes.
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