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czerial
 Post subject: vacumme advance
PostPosted: Thu Sep 15, 2005 5:55 pm 
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So do you need the pipe? i have the vaccume advance on Elmos motor (1293) but it is not connected it is just that thing popping out of the dizzy. can i

a) just leave the pipe there open
b) should i seal it
c) should i connect it (the prob there is where abouts does it go to on a HIFF6 carby?)
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GT1360
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PostPosted: Thu Sep 15, 2005 5:56 pm 
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conect it..

send me a pic of the carb


8)
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Morris 1100
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PostPosted: Thu Sep 15, 2005 6:15 pm 
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Connect it and improve your fuel economy. :wink: (btw, it is spelt vacuum)
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czerial
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PostPosted: Thu Sep 15, 2005 6:25 pm 
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thats interesting point. how what exactly do thses things do??
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scotty
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PostPosted: Thu Sep 15, 2005 7:08 pm 
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As the engine speed increases therre is less time between the up & down strokes, so the firing must be advanced to give time for combustion and expansion. This is done by a centrifugal advance timing mechanism which can be supplimented by a vacuum advance unit.
The vacuum advance is operated by a partial vacuum in the inlet manifold. At part throttle, suction pulls on a diaphram. Thiss advances the spark timing by moving the contact breaker points in relation to the cam. With the throttle fully open, there is reduced pull on the diaphram and less vacuum advance. HTH :)

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J_A_M
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PostPosted: Thu Sep 15, 2005 9:33 pm 
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Do all those with Pulsar Dizzies run vac advance, or leave it off?
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drmini in aust
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PostPosted: Thu Sep 15, 2005 9:43 pm 
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J_A_M wrote:
Do all those with Pulsar Dizzies run vac advance, or leave it off?

Most of us leave it off- we are running Dellortos or Webers... :wink:
In this case just leave it open.

If you have an SU, sure you can hook it up- but first make sure the diaphragm doesn't leak. Many do. Suck on the pipe to check.

re Scotty's discourse above- the vacuum is connected adjacent to the throttle plate, not directly into the inlet manifold. At full throttle, there is really no vacuum advance at all. At best, it is a part throttle economy device.
Racers don't use them, it is just something else that can go wrong.

BTW- Cooper S, (& many other A series), Alfa Romeo and Fiat didn't have them fitted.

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Steve
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PostPosted: Fri Sep 16, 2005 11:41 am 
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Softens the spark connect it, can get away without it for a while but if car is used regulary connect it.

steve
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drmini in aust
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PostPosted: Fri Sep 16, 2005 3:35 pm 
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Steve wrote:
Softens the spark connect it, can get away without it for a while but if car is used regulary connect it.

steve

Maybe? on an antique Lucas, but does not affect spark intensity on a Pulsar (Hitachi) dizzy... :wink:

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:
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czerial
 Post subject:
PostPosted: Sat Sep 17, 2005 11:58 am 
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problem being my carby doesnt have the connection for it
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GT1360
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PostPosted: Sat Sep 17, 2005 12:00 pm 
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swap it to my HS6 :lol:
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h0nk
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PostPosted: Sat Sep 17, 2005 2:45 pm 
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can you connect an advance with twin HS2s?
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drmini in aust
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PostPosted: Sat Sep 17, 2005 2:49 pm 
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h0nk wrote:
can you connect an advance with twin HS2s?

Cooper S didn't have it but the Coopers did (on LH carb). So technically the answer is yes.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:
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GT1360
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PostPosted: Sat Sep 17, 2005 3:18 pm 
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yeah Kev is right. I had vac advance on my old twins. conected to the left. right was blocked off from memory

:wink:
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