[updated:LAST EDITED ON 10-Nov-02 AT 02:43 PM (EST)]All right, something new to post about. Resealed as I posted yesterday. Finished it up today, fired her over and still idles rough, I'm guessing the sound I hear is a major vacuum leak. I had a length of hose out trying to find a possible source of leak, and she cut off and died. I went around and restarted the truck, cranked a couple times then caught, ran for a second and let out one mother of a hugh backfire through the exhaust. What have I got going on here? What is that a characteristic of? Being a newbie, doesn't the carb make a slight "sucking noise"? Is that what I'm hearing and confusing with a vacuum leak? Pretty positive I had the dis in right this time also, so I must have a serious problem then. Any insight would be great, Thanks Blair

 

[updated:LAST EDITED ON 10-Nov-02 AT 05:45 PM (EST)]Let me jump in and say I think George was probably right before when he mentioned timing. I restarted the truck after changing my shorts (I.E. major backfire), and checked some more. Can't find any leaks using the hose method and spraying damn near a whole can of carb cleaner. My friend stopped by thinks its timing, it is really missing at idle, the dis must be off a tooth off. Or the other thing I thought of, I had to rotate to TDC last week, maybe on my exhaust stroke instead of compression stroke? I didn't check valves when I did it, I just rotated while watching the screwdriver. I gotta get it to run again, my flowmasters are sitting in my bud's exhaust shop waiting on me. Gonna try again later this week, Thanks for input, Blair

 

Check my post in the 73-79 forum. If the piston came up and the timing mark on the balancer was lined up with the timing tab, then it should be on compression stroke. Try turning the dizzy clockwise a little bit to see if it runs any better. Also back out your air/fuel mixture screws on the carb about 2 turns until you get het going then you can readjust it. You should hear quite a bit of air sucking into the carb. You are feeding alot of cubes. Set your initial timing to 12btc. Hook up the vacuum advance to the ported vac on the carb. Holley it is on the passenger side about 1/2 way up in front of the choke assembly, on an Edelbrock, it is the left small port on the front left.
Also, don't forget to check those plug wires to make sure that they are on the right plugs, and check the dizzy cap for cracks or moisture.
Jimmy

 

Thanks for info. My mech budd asked me this...."Are you sure when putting on your new gears and chain, you didn't rotate the crank independantly from the cam somehow?" I don't remember doing it that way, I used the old gears and chain to align my marks and checked with a straight edge. HOWEVER, even with the valve covers off, I don't remember looking at the valves to see which one was open or closed. So my next question, if I rotate her around and line up the "0" with my pointer, and my piston is apparently all way up (using wooden dowel, watching it travel), is it safe to say I should open valve cover and actual look at the valve? I don't know which valve is which? Is there any way to see if the crank is out a half turn with the cam after all is said and done? I don't remember rotating without the gears and chain on but who knows what stupid thing I have done, I just want to try and make his diagnosis easier for him. Also have double checked the wires, I have those on the right leads. Any input is great guys, Thanks again, Blair

 

If you've checked the timing, and it's on #1 at the compression stroke and the timing pointer is at TDC, and the rotor is pointed at the #1 wire in the distributor cap, it may be time to again go therough the hassle of removing everything and make sure you correctly align the cam/crank gear timing marks. Until you're sure of that, you can spend a lot of time going through the motions. And at this point, I know you can probably do the intake manifold in your sleep.

We've all been there one way or the other. Anybody who hasn't is extremely lucky or has never torn down an engine.

 

[updated:LAST EDITED ON 12-Nov-02 AT 09:03 PM (EST)]Piston on TDC, BOTH valves closed.