Alternator not charging at idle

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iamtherealJayy

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I know how to get an idea of tdc but how do I get it exactly at top dead center?
Edit: the timing tab on the engine is one that goes in two of the timing chain cover bolts. I may pull those two bolts and see if I can straighten it or find a different one and see if it’s accurate
 

Trucksareforwork

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I know how to get an idea of tdc but how do I get it exactly at top dead center?
Edit: the timing tab on the engine is one that goes in two of the timing chain cover bolts. I may pull those two bolts and see if I can straighten it or find a different one and see if it’s accurate
Easiest way is with a cylinder stop. You install the stop and then turn the motor (manually) until you bump the stop..then ease the stop out until you stop stopping the piston. That's at TDC. Of course you do this on the compression stroke and you can see that by watching that the rocker arms aren't rocking during the stroke. If you have that sort of timing tab you can bolt a new one on pretty easily.
 

iamtherealJayy

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The tab was on backwards, one bolt too low, and bent. I cleaned it and straightened it and got it back on. I’ll try and see where it’s showing the timing at and see if it’s even remotely close
 

iamtherealJayy

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Timing shows 12° advanced. It was at around 15 I brought it down to 12. Mechanical advance seems to work aswell. I set timing at 12 and I’m working on getting highest vacuum but the mixture screw on drivers side is really hard to turn. Any suggestions?
 

Trucksareforwork

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Timing shows 12° advanced. It was at around 15 I brought it down to 12. Mechanical advance seems to work aswell. I set timing at 12 and I’m working on getting highest vacuum but the mixture screw on drivers side is really hard to turn. Any suggestions?
Moving down to 12 likely helps your hot start issue. 15 is quite a bit of timing (though not crazy) depending on the motor. Looks like you have a 350, so you should be alright. Lots of 80s motors ran with single digit advance, so you might play around with a little less base timing.

Couple of checks:

- Is the 12 with the vacuum advance disconnected? It should be. That's your base timing. If you haven't disconnected the vacuum advance (and plugged the hose) to check timing, then do it over and disconnect it.

- You said you have mechanical advance, and that's fine and good. You probably won't turn the motor too high so it's just good to know that it isn't stuck.

- Is your vacuum advance connected to ported / timed vacuum or to manifold vacuum? That can make a big difference in how the truck runs. You probably want ported on your truck unless you have a moderate cam, then manifold can help with idle and runability.

After all this, THEN set your idle speed and only THEN do you want to start monkeying with mixture (and keeping idle steady with the idle screw as you dial in the mixture)

- Finally, on the q-jet (assuming this is the same truck as your quadrabog post), be sure you get a good look at the mixture screws. In my experience, they can be hard to fit a driver to, and sometimes you think the screw is stuck when in reality you don't have your driver on the screw. If it's super stuck, I would ONLY turn the screw outward and then ONLY remove the screw and clean it up to make it easier to turn. IF you apply a lot of torque inward on the screw you can muck up the needle.
 

iamtherealJayy

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Yes, 12° initial without vac advance
Vac advanced is ported
For setting idle speed do you not set the idle screw for 0 vacuum at idle but starts pulling vacuum as you barely touch throttle? Transfer slots a squareish shape? I’m happy with the idle speed of it currently, I don’t have a tach but it idles smooth and doesn’t lurch in gear.
I set the mix screws to highest vacuum, I got up to 18/19 at idle it’s probably around 1-3/4 turns out maybe closer to two.
Yes, I actually had a short stubby flathead and a longer one because one side had the rad hose in the way and other side had a heater hose in the way. Finally got myself with the fan blade however. Surprised I let it happen, but also surprised it’s the first time it’s happened. Fan smacked me right in the forearm a little below my wrist. I got the screw loosened, I spritzed a little pb blaster on it and turned it outwards a little and then just went back and forth half a turn until it was moving freely. Oh and yes this is the same truck as the quadrabog thread. It’s running fairly decent currently it will spin all four in a launch off pavement.
 

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If you got to 18/19 inches of vac at idle I suspect you are doing ok.

Your comment on setting idle for zero vac in the ported line sounds wrong but may just be a method I haven’t used. You want to set idle to the right spec for your truck. Usually something like 550 - 600 rpm warm, in Drive for a stock cam.

Is it starting better when warm? That timing adjustment should help.
 

iamtherealJayy

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Yes, like I mentioned in the other thread, the starting issue is intermittent so I’m thinking I’ve got a ground or heat issue, rather than timing. It’ll crank slow then fire I can shut it off and it’ll crank fine.
 

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@iamtherealJayy,
show us a pic of your battery posts. I can't tell what you've got other than it's a side post. Also, take that neg. ground off your alternator support bracket and with something abrasive clean that spot free of any paint, rust, dirt where the end of your battery cable touches the bracket, and use a large star washer under the flat washer under that bolt so you know you are getting clean metal contact on the bracket. My ground cable is on the frame right across from the engine with the star washer setup. Also make sure your engine is grounded well back on the firewall behind that right head. I see the ground strap but take it off and clean the paint, rust, dirt from where the screw goes into the firewall metal and reattach the screw. The more grounds the better.
 

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So I’ve had this 1976 Chevrolet K10 for around 8 months now and it has never seen pavement the whole time I’ve owned it. I still need to do some tuning on the quadrajet to get it running ideal, but it’s got an electrical issue. The voltage gauge shows 12 at idle and only goes down from there, wipers super slow etc. if I breathe on the throttle and bring the rpms up the voltage is fine. The truck has a brand new alternator and battery. If I leave the truck idling for a while then shut it off and try to instantly crank it again it cranks really slow for a few rotations and either fires up or starts clicking like a dead battery. The starter is new I think I can’t really remember I’ll have to check.
Sounds like a bad voltage regulator or alternator brushes.
 

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