Ignition problem

[sgt1022]

I have a 71 C10 w/454 .030, iron oval port heads decked.010, .500 lift cam, factory LS6 domed pistons, Performer RPM air gap and performer carb, 140 gph electric fuel pump set @ 5psi, HEI dizzy, ACDelco r44t plugs gapped @ .035. I have set TDC twice and cannot get the engine to fire. Are my gaps to close? I have replaced rotor and ignition control module and it still won't start.

[msgdsrf]

You get the carb to squirt and bowls are filled? Then next is are you actually getting spark?

[Lee H]

TDC twice, did you get a different mark the second time? Are you getting spark? When you open the butterflies is gas squirting out? What method did you use to set the lifter preload? Do you have 12 volts at the distributor with key on?

[sgt1022]

Carb is squirting. Sorry I reset TDC pulled dizzy and reinstalled to make sure I had correct position. I have hydraulic lifters. I am getting 12 volts at coil. It fires sporadically after sitting a day like it wants to start then stops firing.

[geezer#99]

Fresh installation?
You might be 180 degrees off. Firing on #6 instead of #1.

[sgt1022]

Should I try gapping plugs to .040 - .045 with the HEI? Right now the plugs are at .035

[Wrenchbender Ret]

The plug gap will not make any difference as far as starting. In fact the closer gap would be better if the spark is weak. Take one plug wire off the plug & hook it to an old spark plug. Lay it on the engine & crank it over. A spark should jump the gap everytime that cyl fires.

[msgdsrf]

Gap won't make a difference. Has to something else.

How about timing? Do you know or have a an idea where you're at? Distributor cap off, engine a TDC, look at roter . It should be a little ways before (Counter-clock) the plug wire connection.

[sgt1022]

Ok checked for spark. none there. going to replace pickup in distributor.

[sgt1022]

OK, getting frustrated. I have power going into coil. I've replaced coil, ICU and now pickup still no spark. What gives? I am clearly missing something. #1 cyl. at TDC on compression stroke. Distributor installed with rotor pointing toward #1 cylinder.

[davepl]

Well if you have no spark and it's not a diesel, everything else is irrelevant at this point. Don't matter where TDC is if you don't fire the plug.

Didn't accidentally connect the coil + to what is actually the Tach input by mistake?

Lower housing harness plugged in correctly?

It'd still run, but you need a full +12V, so you can't use the old white resistance wire (you have to go right to the IGN on the fusebox).

[LockDoc]

-
The ideal power source for the HEI is a wire from the back of the ignition switch that is hot when the ignition is on but many of us use the "IGN UNFUSED" terminal on the fuse block. There are two male spade terminals in that location and either one will work. Run a wire from the "BAT" terminal on the distributor to one of the "IGN UNFUSED" terminals on the fuse block.

LockDoc

[sgt1022]

I rewired the truck with a Painless harness. It ran fine with the small block until I had a lifter fail and chewed up a camshaft. I used the same HEI out of the small block when I installed the big block. Coil+ is in the correct spot. getting12+ volts to coil.

[Wrenchbender Ret]

Did you check or replace the pickup coil. Check the rotor real close. An carbon tract can go through the rotor from the electrod to the advance mech. on the other side.

[sgt1022]

yep replaced pickup coil and rotor. Found loose connection between coil and ICM fixed it now she has fire. she tried to start but kept backfiring through carb. Thought 180 out. Turned dizzy 180 and no starting just sneezing raw fuel out of carb. never had that happen before. I pulled dizzy reset #1 to TDC on compression. Put dizzy back in with rotor pointing toward #1. wired plug wires accordingly. Same thing tried to start but then backfires through carb. suggestions?

[Wrenchbender Ret]

Check the plugs. They may be carboned up from raw gas not being burned. Try advancing the timing. Could a valve be stuck or adjusted down too tight?

[Sklptrljay]

So if everything is hooked up right but no spark I'm thinking it might be a bad ground. How well is the block grounded to the frame and body?

[Sklptrljay]

Didn't read all the way through, I see you finally got it to spark.

[geezer#99]

If it tries to start then backfires thru the carb just keep advancing the distributor until it runs.

[davepl]

Turn the distributor as mentioned as far as you "need" in either direction and see if it runs properly that way.

How did you adjust your valve lash? Maybe you cranked one down far enough that the intake valve is hanging open and it's barking back up the intake.

Just FWIW, a lot of people have trouble finding zero lash. Actually I'll go stick a thread in the main section about it, look there.

[68C15]

A few years ago I did a thread on starting a new engine. It was so detailed it even included when to take a bathroom break. Can someone do a search and find it buried in the archives?