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trouble setting ignition timing


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i bought a not-so-running 75 with an 81 ZXT swap and im having issues trying to set the timing to 20*BTDC.

 

i have brought the Crank sensor to its lowest point and turned the dizzy as counter clock-wise i could. Yet im still advanced at 22 1/2*.

 

The car does have an odd stumble at times and the rpms rise up for a bit every few minutes. When the rpms rise up my timing gun doesnt seem to get a signal.

 

heres an interesting note. It idles slightly better at the setting i found the car which was at 30* BTDC

 

please help a newbie out

thanks

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i bought a not-so-running 75 with an 81 ZXT swap and im having issues trying to set the timing to 20*BTDC.

 

i have brought the Crank sensor to its lowest point and turned the dizzy as counter clock-wise i could. Yet im still advanced at 22 1/2*.

 

The car does have an odd stumble at times and the rpms rise up for a bit every few minutes. When the rpms rise up my timing gun doesnt seem to get a signal.

 

heres an interesting note. It idles slightly better at the setting i found the car which was at 30* BTDC

 

please help a newbie out

thanks

 

Did you get this figured out yet?

 

Did you disconnect the vac advance while trying to reset the timing? Just a thought. If you have too much vaccuum at idle your timing will be off to start with.

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i thought the 81's didn't have vac advance? where do i disconnect this and is it supposed to be set at 20* with it disconnected?

 

Well, good point. If you don't have a vac hose from your intake to your distributor then you don't have a vac advance.....my bad.

 

Look to see if you have a vac line going to your distributor. :) You should always set the timing with the vac advance disconnected. ;)

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Well, good point. If you don't have a vac hose from your intake to your distributor then you don't have a vac advance.....my bad.

 

Look to see if you have a vac line going to your distributor. :) You should always set the timing with the vac advance disconnected. ;)

 

Phleb - Turbo Dizzys have Crank Angle Sensors, no vacuum advance.

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  • 2 months later...

i forgot i had this thread open as its been a while since i worked on the car.

 

i took a few pics so i can show you all where things are ligned up. this is with the #1cyl at tdc compression stroke

IMG_0001.jpg

 

and here is the dizzy set up in order to get the timing where its set.

IMG_0001_1.jpg

 

 

and heres a pic of the TB...looks to me im missing of a few things such as the idle screw? unless the 81's didnt come with an idle adjustment screw

IMG_0001_4.jpg

 

and because i really need this figured out asap here is a pic of the cam

IMG_0001_3.jpg

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