darktideryezing

Hi all,
I have an 81 Trans am with a 350 in it. Edelbrock carb/intake. I've just recently rebuilt the engine. I've got a new double roller timing chain kit on it and I re-used the old balancer because nothing seemed to be wrong with it.

I've got everything in the car and the car can run. But I can't get the idle back down to the idle point for the cam (1000-5200rpm range). I have to keep the idle somewhere above 1500 or it'll start going irratic (it will go up and down between 1000-1500) and just die off. It diesels. And you can feel that something is not quite right in the exhaust pulses. And sometimes it will backfire through the carb. I can't seem to find a trend with the backfiring.

Obviously the timing is off, but I just can't seem to get it down correctly. When I put the timing light on it the mark is at 12:00. And when I try to bring it down to the timing tab it goes to hell and dies out.

I've heard several different theories. So far is that when I put the timing chain on one link off. I doubt it as I followed instructions and the timing marks were inline (not a perfect line but I tried one notch in each direction and it didn't work). I've also read that I could have switch a spark plug wire. I know that I'm not numb enough to have put the timing light on the wrong plug. I'm going to retry again Sunday and double check some things but I have no idea what could really be wrong. I'm really hoping that the timing chain thing is not true because That's a horrid job that I'd prefer not to end up doing on my back in a gravel drive way because I have no other place to do it.

So if anyone has any advice, tips, or need more information from me please let me know. At this point I need all the help I can get. Thanks to anyone in advance.

Darktide

Nixon1

That surging with the cam, sounds like the carb is giving too much fuel and that's why you have to keep the idle up, otherwise it'll start to flood. Try giving it just enough timing to keep it running, then play with the carburetor, get it to idle properly, and then tweak the timing some more.

Also something to think about, you may have stabbed your distributor in off a tooth. Which means, all the plugwires will need to be shifted over, or you'll need tto re-stab it. It could just be that you're off a tooth and you can't get the necessary adjustment out of the timing because of that.

darktideryezing

that was something I had thought about. I'm going to give that a whirl tomorrow. I also wonder if I misplaced the distributor cap though i'm 99% sure that it shouldn't be. The fuel shouldn't be going that much over because I've reset the carb screws several times (get until finger tight then turn 2 full turns out). I'll try bringing them back in 1/4 until things work out. Thanks for the help Nixon. I've been praying my butt off that it wasn't the timing gears because I just don't have the place nor the time to do that kind of work.

Darktide

SickSickSick

just ran into someone who had the same problem. turns out he had to get a different harmonic balancer. the timing marks were no longer true with his new engine mods. forget the marks and try timing it with a vacuum guage ( seeking point of most vacuum ). good luck. Sick

darktideryezing

that's a good idea. But i'm pretty sure that my balancer is ok. I had to time the ignition before the rebuild and it was spot on. Unless when I smacked it with a hammer a few bazillion times during installation I f-ed it up. I'm going to try moving the distributor 1 tooth over turn down the fuel mixture screws on the carb tomorrow when I fix the speedometer. Though I may just take a good look at the cap first and see if its just not on the wrong spot. Thanks for the info though, I'll keep it in mind.

Darktide

Nixon1

The balancer is marked relative to TDC, that's not going to change no matter what he does to the engine. He probably damaged it on install, or the outer balancer ring spun, moving the marks....that's common on stock-type 2-piece balancers.