Trying to tune up a 305 sbc with vac advance, and an edelbrock 600 carb. I have hit it with a timing light and have it dead on. but I cant get the fuel air mix right on the carb. It seemed like my fuel pump was feeding to much to the carb. So I added a presure reg. set at 5 pounds first then 4 pounds. Both times I got a fire ball about 8 in off the carb.Have taken the vac off the carb and tried to ajust the set screws and the throdel (sp). Still blowing flame ..... Now what am I doing wrong
I'm no carb guy, but I say trash the edelbrock and bolt up a Holley or Demon or Carter. I've had nothing but bad luck with Edelbrock carbs.
Are you SURE you have your timing set right? Pull the valve cover off on the bank with the #1 cylinder. Turn the motor over and watch the intake valve open and shut. TDC should be about 1/3 turn past that. This is the way to absolutely sure. Is the distributor a tooth off? If you're backfiring up through the carb, that sounds like a timing issue, not a carb problem. That carb could be dialed right in and if the timing is off, it'll still do that.
Are you sure your advance is working? Are the 5 & 7 spark plug wires crossed? Is the time out 180 degrees? jerry
I have an edelbrock, holley, and demon sitting on my shelf. The eddie is by far the best street carb. Set it and forget it. I would check for va***n leaks since it sounds like you have a lean backfire or a pair of sparkplug wires crossed.
I just went through hell with my 350.Tried everything I knew, it ended up being the balancer had slipped the outer ring slightly.Power timed it on a steep hill now it works great.
Fire through the carb is ignition before an intake valve is closed has to be off or plug wires crossed. Did you replace any plug wires or have the distributor out on your tune-up. Had a similar problem on my son's car seem he put new wires on one position off on the distributor cap. I'd put #1 cylinder at TDC see where your timing mark is and also look at plug wire #1 position on the distributor cap in relation to where the rotor is pointing. You didn't say if you replaced any parts I'm ***uming you did as in tune-up.
Let's think about this with facts. First, for a fireball to come up through the carb, mixture is igniting while the intake valve is still open...so that's why ignition timing is being so heavily covered here. All good advice too- by the way. So, the spark is firing too EARLY...it's too far advanced. Try this: Set the timing (with the vacuum advance line disconnected and plugged off from the vacuum source like the intake manifold) at 32 degrees with the engine at 2,500 rpm or so. Shut it down, reconnect the vacuum advance line to the distributor, and start the engine again. What's it doing now? If it's just as bad, or worse, the timing marks may be off. If so, they're useless and you have to find number one cylinder TDC. The BEST way to do this is with a stop bolt in the spark plug hole, but if you've never heard of such a thing I'll explain it. By modifying a spark plug by gutting it an replacing the internals with a stop bolt (basically installing a longer bolt into the plug housing and cutting the bolt head off), you have a piston stop. install this stop into the number one hole, and rotate the engine SLOWLY BY HAND using a socket on the crankshaft bolt. When you feel the piston hit the bolt and stop, mark the balancer. Now, rotate the engine in the other direction SLOWLY BY HAND until the piston once again stops on the bolt. Mark the balancer one more time. REMOVE THE PISTON STOP AT THIS TIME. You now have two marks on the balancer- measure the distance between them and mark the exact center. This is TDC- the top-dead-center point of the number one piston. There's no better way to find it. If the balancer is incorrectly marked, this procedure will show it. It will also show if the balancer is marked correctly, of course, and if so you can move your diagnosis elsewhere. If you don't have the balancer marked correctly for TDC, you will be chasing your tail until you get dizzy. Check this out, and tell us what you find. If you ***ure me the balancer is marked correctly, we'll continue this internet tuneup procedure and I promise we'll find the problem. Scotch~!
There are lots of people on this board who are going to be asking how to set up their cars to get fireballs out of the carb...exhaust fireballs have already been covered.
That's funny Bruce! I can only help 'em get fireballs in their combustion chambers... Just another one of my shortcomings I guess. Scotch~!
my dad had a 305 that did that, turned out to be a flat lobe on the cam. weird how **** happens like that. new cam, same everything else and then it ran great. that is probably not the case here, though.
Ok thanks for the help I'll get out there tonight and see what's up. I took the distributer (sp) out when I changed the trans (easier to get to the bolts on the bell housing it's a tight fit in a 54 plymouth ) Could I have skiped a tooth when I replaced it? It wasn't doing this before the trans swap. The plug wires are right.....
It's offical I'm a dumb*** ..... Forgot that I took the dis. off when I changed out my trans.... I had to turn the pressure plate to take off the torc converter .... Top dead center, reajust dis. and set. Now it runs like a ****d ape Thanks everyone for the help
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