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Timing your car with a vaccum gauge?

  • Thread starter Thread starter CrawlinSlo5.0
  • Start date Start date Sep 23, 2009

CrawlinSlo5.0

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#1
  • Sep 23, 2009
  • #1
So ive been having issues with timing my car and someone told me you can time your car with a vaccum gauge. Any inshight or articles on this and how to do it?
 

jrichker

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#2
  • Sep 23, 2009
  • #2
That technique works good with carb cars, but isn't suitable for EFI.

With a carb car, connect up the vacuum gauge, loosen the distributor hold down bolt and start the engine. Turn the distributor until you get the highest steady vacuum reading and tighten down the distributor hold down bolt.
 

CrawlinSlo5.0

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#3
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that is awesome! Im going to do that tomorrow! Is it more accurate than using a light? Should i just let it idle and turn the distributor or put it under a load?
 

HISSIN50

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#4
  • Sep 24, 2009
  • #4
CrawlinSlo5.0 said:
that is awesome! Im going to do that tomorrow! Is it more accurate than using a light? Should i just let it idle and turn the distributor or put it under a load?
Click to expand...

The base timing setting is one tiny (and relatively unimportant part) of ignition timing. Are you able to recurve your ignition (either mechanically or electronically)? If not, deviating much from the standard 10-14* is asking for issues.
Being able to use a timing light is a step forward, not backwards.
 

jrichker

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#5
  • Sep 24, 2009
  • #5
CrawlinSlo5.0 said:
that is awesome! Im going to do that tomorrow! Is it more accurate than using a light? Should i just let it idle and turn the distributor or put it under a load?
Click to expand...

Did you not read where it said that using a vacuum gauge to set the timing on an EFI engine wasn't a suitable plan?

jrichker said:
That technique works good with carb cars, but isn't suitable for EFI.
Click to expand...

Heed Hissin50's advice about limiting the total advance either by electronic or mechanical means any time you go outside the 10-14 degree inital advance figure.

When I worked on carb cars and wanted more initial advance, I always added a bit of rework to the mechanical advance mechanism. The plan was to limit the total advance so that it did not exceed 38 degrees. This required a distributor test machine and some effort to get it set up and working with a smooth consistency.
 

CrawlinSlo5.0

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#6
  • Sep 24, 2009
  • #6
my car is carbed. so i dont have to put it under a load then?
 

CrawlinSlo5.0

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#7
  • Sep 24, 2009
  • #7
I also have anoher question. When adjusting your idle mixture screws. How many turns should you start out with. How do you know when its set right? Im new to carbs if you cant tell lol! Just learning as i go. I figure at the rate im going ill be a pro at adjusting my carb real soon! lol
 

CrawlinSlo5.0

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#8
  • Sep 24, 2009
  • #8
i hooked up the vaccum gauge to the vacum advance on the distributor and the metering block. At idle it pulls no vaccum but when under a load it pulls vaccum. When you turn the distributor either way the gauge doesent fluctuate at all. Im lost.
 
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