WOP'R Posted September 5, 2009 Share Posted September 5, 2009 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 Quote Link to comment Share on other sites More sharing options...
WOP'R Posted September 6, 2009 Author Share Posted September 6, 2009 BUMP been searching for a few hours and still cant find anything Quote Link to comment Share on other sites More sharing options...
Phlebmaster Posted September 9, 2009 Share Posted September 9, 2009 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. Quote Link to comment Share on other sites More sharing options...
WOP'R Posted September 10, 2009 Author Share Posted September 10, 2009 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? Quote Link to comment Share on other sites More sharing options...
Phlebmaster Posted September 11, 2009 Share Posted September 11, 2009 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. Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted September 11, 2009 Share Posted September 11, 2009 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. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted September 11, 2009 Share Posted September 11, 2009 The fact that he had adjusted the crank angle sensor to it's lowest point and still has 22 degrees might suggest the throttle position switch is not closing when throttle is closed...........or his throttle is not closed. If the car is above the specified idle, the timing will be advanced as well. Quote Link to comment Share on other sites More sharing options...
roger.svoboda Posted September 11, 2009 Share Posted September 11, 2009 Oil pump could be a tooth off that would explain why you can't get to desired setting. Or pulley slipped. might want to crank it to TDC compression on #1 (both cam lobes pointing up) and see where the timing marks are. Quote Link to comment Share on other sites More sharing options...
WOP'R Posted November 28, 2009 Author Share Posted November 28, 2009 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 and here is the dizzy set up in order to get the timing where its set. 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 and because i really need this figured out asap here is a pic of the cam Quote Link to comment Share on other sites More sharing options...
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