sbc problems

ok im haveing a time with this sbc . so i was wondering if theres any gurus out there that may beable to help. so im haveing hard starting problems . i have to turn it over spin the dizzy and just fuck with it to get it to start but when it starts it runs like a top. im lost now . the thing runs perfect once its started ! i set the dwell at 30 i adjusted the valves and then re checked them , i set the timing at 36 degrees full advance carb is set at 2 1/2 turns . but its almost impossible to get the ting started anyone have any ideas why the hard start
it s a rebuilt 350 , mild cam, edelbrock 600 , stock ram horns nothing fancy

thanks for iany info

 

i had the same problem on a sbc stroker,a new hei distributor and msd 6al box fixed it. i usually set air-fuel screws bout 1 1/2 turns out

 

I'd have to ask what your start up procedure is first. If you are used to driving FI cars the carburetor equipped cars can be a pain until you develop a starting procedure that the engine agrees with.

Normally it is get in, push the pedal to the floor to get the choke to close, hit the accelerator pedal a couple of times to get a good shot of fuel and crank the engine over and it should start.

You do have the resistor bypass wire hooked to the starter? They like that full 12 volts to start especially when cold and some ignition switches don't put a current through to the coil when they are in "start" position as they are designed to work with the resistor bypass. If you crank it and it doesn't fire but fires when you let off the key that is the problem.

And I'm with Jworbes in that I normally start out with 1-1/2 turns on the idle mixture screws and then dial them in with a vacuum gauge after I have it running.

You may have a bit more timing set in it than it wants for starting purposes too. What does it have for timing at an idle? If the distributor wasn't set up in a distributor machine to get the proper advance you may be giving it too much initial advance in order to get that particular total advance.

 

Sounds like an older car if it has points. The old 60s chevys had a resistor wire to drop the running voltage way down on the points. During cranking, there is a by pass wire to the coil to feed full batt volts. I think even older ones had a ceramic resistor.

Do you know if your coil has the by pass wiring still hooked up? It would be a wire from the outboard small terminal on the solenoid marked "I". Then it goes up to the plus side of the coil.

 

<" i have to turn it over spin the dizzy and just fuck with it to get it to start but when it starts it runs like a top." Does 'spin the dizzy' mean you move the distributor while cranking it? If so, you are probably retarding it enough from the (perhaps) 36* full advance to help it to start. Do you know if the 0* mark on your timing tab truly reflects TDC ? Have you measured the amount of mechanical advance in the distributor? I would start our by finding TDC and verifying the 0* on the timing tab , remarking/moving as necessary, and then reinstalling the distributor. Set the timing at 10 or 12* BTDC and go from there. vic

 

the 0 mark is the true tbc

 

opps i ment 1 1/2 not 2 1/2

 

never owned a fuel injected car in my life .its a electric choke.

 

ikve tryed it hooked up and bypassed

 

When it's cold, remove the air cleaner and watch to see if there is fuel from the accelerator pump when you work the throttle. It could be that the checkvalve in the fuel pump is letting the fuel drain back into the tank after shutdown and you have to crank it until the pump fills the float bowl again. If no accelerator pump shot, pour some gas in the carb and it should start but will need to be repeated a few times 'till the pump gets fuel to the carb. If you do have an accelerator pump shot, then disregard the forgoing.

 

new fuel pump and carb i havent had a air cleaner on it yet but it is getting gas

 

I have seen MANY Edelbrock carbs that when they sit for a few days seem to bleed down the fuel in them. It then takes a bunch of cranking to get fuel back in them with a mechanical pump.
Do you have a mechanical fuel pump or electric?

 

mechanical fuel pump. and the carb has gas

 

Timing to far advanced! 8 degrees BTDC is the norm for a sbc... Also, use a vacuum gauge to set the idle mixture screws. Your motor will love you for it.

 

If you are playing around with the distributor to start it, I'm wondering if the timing gear is off a tooth or two.

 

Are you setting the timing with vac advance connected or not. Are you certain the timing mark on your balancer and pointer are correct. Factory style balancers are prone to the outer ring slipping and making your "0" mark incorrect.

 

Check the voltage on the + side of the coil while your cranking and make sure you have 12v. If the wiring has been "customized" the ignition may be on a circuit that has a heavy load on it when the starter is engaged. A quick test can be done with a jumper wire from the battery to coil.

 

its a brand new wiring harnes and i tryed to jump straight power already

 

vac advance id disconnected .. yes i toped out the enging and checked where the timing mark was

 

ive pulled the dizzy two times to make sure it was right both times it was dead on

 

maybe due to high compression the startor isent spingin fast enough?

 

Like krusty40 says, might be time to verify if the timing mark is matched with actual Top Dead Center (TDC) on cylinder #1.

There are several balancer diameters, and several different tabs. The two can be mismatched. Some aftermarket tabs are just plain wrong.

I have seen balancers that are wrong too. Some must have been made that way, others had "spun" the outer ring.