4AC ignition timing and distributor issues

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BlackStar
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4AC ignition timing and distributor issues

Post by BlackStar »

I am having my first problem with ignition timing, it way to advanced! i got a timing light and checked, it was around 15 degrees btdc. This may explain the problems i was having when i tired to drive it, it was advancing even further to accelerate.

but its turned into a pain in the ass! I tried rotating the distributor, but all it did was advance it further, i couldnt retard it. i figured the rotor was a tooth off, so i restabed the dizzy in. It wouldnt run at all. Took it apart and saw that the timing was wayoff

I am really pissed now. I have no clue how to install the dizzy, anyone have picture of what it should look like when it is properly installed? Reading just is not cutting it, i need a visual.

dr.occa
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Re: 4AC ignition timing and distributor issues

Post by dr.occa »

Line all of your timing marks up (cam gear, timing belt gear) ATDC. No. 1 should be at the apex/zenith (highest point) of its stroke. Take note of where the cylinder 1 tower is on your distributor cap and make a scribe/scratch on the distributor body indicating that. Remove the cap, line up the markings on the driven gear with the mark on the distributor neck and insert the distributor back into the head. If done correctly, the rotor will spin and line up with or pretty near to that marking you made on the distributor for cylinder 1. Then set your timing from there.

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BlackStar
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Re: 4AC ignition timing and distributor issues

Post by BlackStar »

my car lives again. However, it still has the same problem it had before, and its somehting i still have not gotten an answer for. Confirmed by my timing light, my car is running 15 BTDC. Even after plugging up the dizzy to test/set it, i can only advance timing, not retard(and i need to retard it to 5 btdc wiht the dizzy plugged). I have the dizzy put in so that when its all top dead center, the rotor is contacting the number 1 pole in the rotor cap. Either I am going to get my dremel out and give the dizzy more adjust-ability, or i will have to re-stab the dizzy so it does both point at the number 1 pole, and have the divot/bump line up on the gear/dizzy house(respectively) I can't seem to have both, maybe someone messed up on installing the rotor on my car?

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86boy
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Re: 4AC ignition timing and distributor issues

Post by 86boy »

My cousin is having that exact same issue with his chevy nova with a 4ac in it. He was telling me how he can get it to 15*, but then runs out of adjustment having the vacuum lines plugged just like you state. Although his rotor doesn't get the poles....

Do you know 100% for sure the timing belt is installed correct? or possibly stretched and skipped a tooth or two? Just throwing something on the table. Each cam tooth would be 10* if the picture I looked at was the 4ac cam gear. 360 (degrees in a circle) divided by 36 (teeth on the cam) = 10 degrees per tooth. same as the 4ag(z)e.
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