Help with starting 79 k20 400SBC

[cduneman]

I've got a 1979 k20 pickup with a 400 small block in it, and a brand new edelbrock carb. I just recently rebuilt the engine, and everything was doing pretty good with the old quadrajet that I suspect had jetting issues, it was bogging if i pushed the gas over half way, it randomly sputtered out and died like it wasn't getting any gas. Never started after that, so i threw my new carb on. Edelbrock AVS2 with 650CFM. I know both the old and the new carb is getting gas, and it has spark, and the timing should be close enough to do something. Right now it will just crank forever with no indication of starting. I have the distributor installed at TDC at around the 0* mark on my timing cover. I believe everything is hooked up correctly also.

 

[ali_c20]

Welcome from Austria. Is it tdc or could it be that timing is 180° off? Add some advance, around 8-12. Choke is set up right? Idle mixture screws have a base setting? Spark plug cables are in the right order?
Check everything and if all is right try to start again.

 

[Ricko1966]

Check for spark and check the condition of the spark plugs.

 

[Vbb199]

and it has spark,

What color is the spark ?

 

[Ricko1966]

You can have no carbureator on a sbc,as long as it has fuel,spark,and compression it will start,as long as the distributor is half a$$ close to being in time. Back before I knew what I was doing if we stabbed a distributor on a fresh engine we'd dump a little fuel down the throat of the carb,one guy would crank,one guy would twist the distributor a little bit in each direction,it would light off. We'd twist it until it had best rpm,break in the cam. Change the oil restart,time it on the road,no ping and seat of pants. Check your plugs and check compression.

 

[cduneman]

Welcome from Austria. Is it tdc or could it be that timing is 180° off? Add some advance, around 8-12. Choke is set up right? Idle mixture screws have a base setting? Spark plug cables are in the right order?
Check everything and if all is right try to start again.

Thank you, i have tried flipping the distributor 180 and it just backfires like crazy so I don't think that is correct, and I put the idle screws to base settings, have retarded and advanced the distributor a bunch both ways and nothing... Spark plugs are brand new also

 

[cduneman]

What color is the spark ?

Blue

 

[ali_c20]

Check for vacuum leak. Is the distributor new or the old one? I had a bad module that produced a weak spark and the same with a bad coil. Try to start with starter fluid or brake cleaner, if it doesn't start with that stuff you can rule out the carb of being the troublemaker.

 

[Ricko1966]

Everybody,quit using brake cleaner,looking for intake leaks and as starting fluid,mounting tires etc. Burning brake cleaner creates phosgene gas. ( oh a little won't hurt anybody) yea,how much will? Why take a chance?

 

[Ricko1966]

Thank you, i have tried flipping the distributor 180 and it just backfires like crazy so I don't think that is correct, and I put the idle screws to base settings, have retarded and advanced the distributor a bunch both ways and nothing... Spark plugs are brand new also

Brand new as in installed after the problem or installed before the problem?

 

[ali_c20]

Everybody,quit using brake cleaner,looking for intake leaks and as starting fluid,mounting tires etc. Burning brake cleaner creates phosgene gas. ( oh a little won't hurt anybody) yea,how much will? Why take a chance?

Damn but it works so good...it's like a chemical swiss army knife . Ok, I'll use it for cleaning only in the future as phosphine gas really sucks.

 

[75gmck25]

I’m a little confused about where you are at in your installation.

You said it ran with the Quadrajet, but not very well, so you installed the Edelbrock. Then you later said on you stabbed the distributor with it set at about 0 degrees.

Did it start and run with the Quadrajet, and then you only swapped the Edelbrock? Is the distributor exactly as it was when it ran with the Quadrajet? Or have you never gotten it started after the rebuild?

 

[SQ HAF KRU]

I have you checked to see if you have fuel in the carb...you should see fuel out of the squirter when you move the throttle....does it a mechanical pump?...engine spinning a 300-400 rpm during cranking can take a long time to deliver fuel to the bowls....

 

[Sgt Gus]

Curious on status.

 

[legend57]

It's always good to get back to basics; Fuel, spark, compression

For fuel:
* Is it old fuel. I've run into similar issues with using old fuel
* You mentioned you know you have fuel getting to the carb, but do you know what pressure. May be worthwhile to install a gauge (at least temporarily) to help diagnose. There could be a restriction somewhere.
* If you pump the throttle, do you see the accelerator pump push fuel down the barrels?

For spark:
* I always like to use a Lisle 20610 Inline Spark Tester when I'm debugging. It helps to confirm good spark at the plug. Rules out lots of other items. Just $11 from Amazon.
* I agree with trying to set it to 8-12 degrees BTDC as a starting point.

Compression:
* You mentioned you just rebuilt the motor, but it may be worthwhile to pull the plugs and double check compression on all cylinders. If nothing else, it gives you a baseline for comparison for down the road.
* You may also want to pull the valve covers, just to check everything underneath. I've had rocker nuts back off. Of course, a vacuum gauge would also tell you if you are having valves not opening.