 Vac Advance Unit, Testing |
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| 76-914 |
 Jun 28 2011, 07:42 AM
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#1
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Repeat Offender & Resident Subaru Antagonist  Group: Members Posts: 13,507 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California 
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Is there a proper test for the dizzy vac adv unit? i.e., how many pounds vac and how long should it hold. Also, what about the retard side; the same?
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| r_towle |
Jun 28 2011, 11:48 AM
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#2
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Custom Member Group: Members Posts: 24,585 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
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question.
Does the car idle ok when you pull the advance/retard hose and plug it? You can drive the car without the canister...it just starts the advance faster or pulls the plates back (retard) sooner for emissions. I am pretty sure (but I am certain I will be corrected if I am wrong) that the retard side only pulls the diaphram back from the advance position. It sits at rest with no advance, so you would not be able to move it by applying a vacuum to the retard side....you would be able to hold pressure though. RIch |
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| Cap'n Krusty |
Jun 28 2011, 12:23 PM
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#3
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Cap'n Krusty Group: Members Posts: 10,794 Joined: 24-June 04 From: Santa Maria, CA Member No.: 2,246 Region Association: Central California |
QUOTE(r_towle @ Jun 28 2011, 10:48 AM)  question. Does the car idle ok when you pull the advance/retard hose and plug it? You can drive the car without the canister...it just starts the advance faster or pulls the plates back (retard) sooner for emissions. I am pretty sure (but I am certain I will be corrected if I am wrong) that the retard side only pulls the diaphram back from the advance position. It sits at rest with no advance, so you would not be able to move it by applying a vacuum to the retard side....you would be able to hold pressure though. RIch Wrong. The retard pulls it down from the rest position, the advance pulls it up from the rest position. That way the idle is dropped with the throttle closed (timing retarded), and the timing advanced over time when the throttle is opened (adding to the mechanical advance). Neither side holds "pressure", only vacuum, which isn't measured in PSI, but in inches of mercury. The Cap'n |
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| orange914 |
Jun 28 2011, 03:27 PM
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#4
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http://5starmediaworks.com/index.html Group: Members Posts: 3,371 Joined: 26-March 05 From: Ceres, California Member No.: 3,818 Region Association: Northern California |
QUOTE(Cap'n Krusty @ Jun 28 2011, 11:23 AM) QUOTE(r_towle @ Jun 28 2011, 10:48 AM) you would be able to hold pressure though. RIch Wrong. Neither side holds "pressure", only vacuum The Cap'n Oh Contraire, Neither pressure nor vacuum but "negative pressure" (IMG:style_emoticons/default/stirthepot.gif) |
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| Cap'n Krusty |
Jun 28 2011, 06:06 PM
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#5
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Cap'n Krusty Group: Members Posts: 10,794 Joined: 24-June 04 From: Santa Maria, CA Member No.: 2,246 Region Association: Central California |
QUOTE(orange914 @ Jun 28 2011, 02:27 PM) QUOTE(Cap'n Krusty @ Jun 28 2011, 11:23 AM) QUOTE(r_towle @ Jun 28 2011, 10:48 AM) you would be able to hold pressure though. RIch Wrong. Neither side holds "pressure", only vacuum The Cap'n Oh Contraire, Neither pressure nor vacuum but "negative pressure" (IMG:style_emoticons/default/stirthepot.gif) There are multiple terms and situations covered by the term "negative pressure", and "vacuum" is one of them. Rather than using a general term, I chose one that is more specific as well as being more commonly used in the trade. Neener, neener, neener ......... The Cap'n |
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Posts in this topic
76-914 Vac Advance Unit Jun 28 2011, 07:42 AM
tod914 If you hook your Mityvac up while the advance is m... Jun 28 2011, 09:20 AM orange914 Do you want to check advance curve spec.'s or... Jun 28 2011, 10:38 AM Hammy I've never seen any numbers, I tried searching... Jun 28 2011, 10:54 AM 76-914 When I pulled on the advance side(I refuse to say ... Jun 28 2011, 11:45 AM
underthetire
When I pulled on the advance side(I refuse to say... Jun 28 2011, 12:00 PM Cap'n Krusty You're right, it's bad. Gonna be VERY dif... Jun 28 2011, 12:19 PM r_towle I know it holds a vacuum...
I did not think there ... Jun 28 2011, 12:33 PM tod914 I had wrong vac. units in cars already. Be sure t... Jun 28 2011, 01:05 PM 76-914
question.
Does the car idle ok when you pull the ... Jun 28 2011, 02:59 PM 914_teener The Cap'n
[/quote]
So it should move the arm w... Jun 28 2011, 03:15 PM tod914 Made some difference when I put the proper one on.... Jun 28 2011, 03:43 PM SLITS Hey Kent .... I have some new negative pressure va... Jun 28 2011, 07:55 PM Dave_Darling The factory manual has diagrams of vacuum versus d... Jun 28 2011, 10:51 PM 76-914
The factory manual has diagrams of vacuum versus ... Jun 29 2011, 08:38 AM Dave_Darling Wow, I really thought the charts had made it into ... Jun 29 2011, 11:29 AM 76-914 :agree: but then again many things are a pita unti... Jun 29 2011, 04:25 PM |
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