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How to Tune your engine with a VAC gauge!


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#1 Tiny

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Posted 07 March 2007 - 01:44 PM

Thanks to ALX76 for finding this info with a great animation!

http://www.secondcha.../public/186.cfm

#2 _LX8VD69_

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Posted 07 March 2007 - 06:29 PM

thats a pretty good explaination only it fails to tell you how to adjust your timing using one

#3 TerrA LX

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Posted 07 March 2007 - 06:51 PM

If you look at senario 1 and compare it to senario 10 you will see that you need to have the highest possible vacuum possible.
This is obtained by advancing the dizzy till the vac guage stops comming up, usually you back it off a tad and see if it drops a little to ensure you haven't gone too far, check it and cross reference with a timing light, and then set the mixture the same way, this also helps with run on as you can get the idle screw in as far as possible. Rock the mixture screw as well to see you haven't gone too far too.
always, as recomended, set a base line for hot cams as they will give a lower vac reading due to the lumpy idle.
If it pings on setting it up this way i would assume you need higher octane fuel or your advance is comming in too soon or you have too much total advance dialed into your dizzy.

Edited by ALX76, 07 March 2007 - 07:05 PM.


#4 TerrA LX

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Posted 07 March 2007 - 08:01 PM

^ or should that read "idle screw out as far as possible" in other words the throttle will be as close to closed as possille whilst still enabling the car to idle.
This will allow the idle circuit to fully function and stop the carb pulling fuel from the main circuit.

Edit; i have found that you may have to go back and forth between the dizzy and the carb once or twice especially if the last tuner got it wrong.

Edited by ALX76, 07 March 2007 - 08:03 PM.


#5 _ToranaGuy_

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Posted 27 February 2008 - 11:09 AM

That's actually very cool and may very well help me getting the carby right on my Panel Van's 253. I need to buy a vac gague.

Cheers

ToranaGuy

#6 _EXLXSL_

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Posted 27 February 2008 - 03:39 PM

This one was on eBay a few weeks ago.

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#7 _maxpower1000hp_

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Posted 28 December 2008 - 09:51 PM

Thanks to ALX76 for finding this info with a great animation!

http://www.secondcha.../public/186.cfm




top site, being using one for years, old school the only way
a vac gauge, a voltmeter, compression gauge, stethoscope and timing light, that`s all you need for a perfect runing motor, l have tried a dyno, waist of time and money, and car lost 2 tenths down the 1/4, or was it the tuner ooh mike

#8 _Big T_

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Posted 13 August 2011 - 04:37 PM

Fantastic link. I just bought a vacuum gauge and it came with no instructions. Now I at least have something to work with. Cant wait to play with my new toy :D

#9 _triumph202_

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Posted 16 January 2012 - 06:43 PM

Just thought I'd post a link to go with this thread: http://www.gmh-toran...qs/page__st__25

Perhaps it should be read in conjunction with the above posts?

I know I have had a play with the vacuum guage method and I seemed to be just advancing the timing further and further......




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