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Engine in, not starting

mouse

mouse

1/2 ton status
Joined
Nov 10, 2003
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Location
Great Falls Mt
Its cranking, but not firing.

The specs: 350, .040 over, summit 1101 cam/lifters (252 intake, 262 exhaust) installed straight up, z28 valve springs, edelbrock 1406 carb, accel hei distributor, electric fuel pump (low pressure) high vol oil pump. Went with flat top pistons-keith black cast and moly rings.

It back fired (sort of) through the carb a couple of times. I brought the balancer back around to zero mark pulled the number one spark plug and looked in, yup, its TDC. Pulled the cap off, and the rotor was pointing towards #1 cylinder.

I have good fuel, thanks to the electric pump. I think its the ignition. I had my wife crank it a couple of times with the timing light hooked up, but I didn't get the light to flash. I pulled the top off the distributor and checked the ground and power by hooking a test light to both (at the same time) and I had good power. The engine grounds are good - I run two and made sure to bring it down to bare metal before I hooked them up.

I guess tomorrow I'll start by changing the cap and rotor ( I used what looked like a good set I found in my wrok bench-the old one was a little worn). I've got a spare coil and ignition module I can swap in as well.

Did I miss anything? Everything sound right? If I can prove the iginition is good, I will have to look at the valve adjustment........
 
Did you pull a plug and ground it while cranking to check for spark?
 
I'll pull a plug tomorrow and see if it sparks instead of relying on the timing light. Although I think the timing light should work while cranking...
 
I changed the cap and rotor and started from there.

Well, when I pulled the plug wire and slipped the boot back, I had my wife crank it with the end near an exhaust manifold bolt. It sparked, but a weak spark.

So, I swapped this cap (and coil) onto my '76 K20, and it started right up. I tried the trucks cap on the blazer, same thing, crank no start. Battery voltage was low, so I hooked up the battery charger. After a bit of charging and moving the distributor the full range of adjustment, it finally backfired through the carb and made a couple of hints of firing. That didn't last as I keep trying different timing settings and the battery lost its charge (makes me believe its a weak spark problem).

I have a good 14.6 volts at the battery wire on the cap. I double checked the wires and all look fine on the coil. I double checked the ground wires on the engine and tested them with the multimeter - both are good.

I'm starting to get a little frustrated. I guess next move is to swap the entire distributor with the truck.

Any other guesses?
 
not to sound like an arse but are you 100% certain your not 180 out?

i've seen many guys do it the plughole way and be on the exhaust stroke... might be worth double checking by the valves with the vc's off...

its not points is it? bad condenser will give ya weak spark..
 
If it is backfiring threw the carb I would guess that your distributor is 180* out. If you are getting no spark there is only a few things that would cause this.

No power to the ignition coil.
Bad Ground to the ignition.
Bad Module
Bad Pickup Coil
Bad Ignition Coil

Harley
 
Last night I checked the distributor with the balancer at 0. The piston was visible, but come to think about it I don't remember if I had the valve cover off. It can't hurt to check again.

But shouldn't I be getting more backfires, some sort of dieseling, etc? It really doesn't sound like its firing...

Its an HEI ignition.
 
yeah, i always do mine by the #1 valves.. spin till the intake valve opens, then closes. the next time the line comes up will be TDC.. before the exhaust opens..

there used to be a neat little tool years ago that was basically a whistling spark plug. thread it in by hand and when it was on the compression stroke it would whistle.. it was pretty neat, haven't seen one in years...

but i always do mine by the valves cuz you generally have the vc's off anyway, and its foolproof... i would double check that... if wrong, ya really don't even have to pull the dizzy, ya can just relace it.. i would double check that, then move onto ignition stuff if ya still have weak spark.. pickup, module, etc...
 
If the valve covers aren't off, just put your finger over the plug hole while you crank it when you should be close to TDC. You'll feel the compression, and if you can see/feel the piston at TDC, you know you are right.
 
I concur. Definately sounds ike 180 degrees out. The piston can be at the top of its stroke but it could be the exhaust stroke that its at the top of. Try bringing the mark to zero, take the dist out and the spin the motor over once. Put the dizzy back in and it should fire.
 
Here's the reasons that I've had a motor not start, or be very difficult to start after fresh rebuild:

1. Spark plug wires in wrong order (after checking twice before)
2. Carb mounting bolts not torqued properly (8in-lbs not ft-lbs)
3. Distributor 180* out.

Maybe that will help. :dunno:
 
Well, I guess I feel pretty dumb...After ensuring I had the engine at TDC for #1, it was really 180 degrees out. I swapped the distributor 180, and it started right up. I guess I'll blame the fact that its been almost ten years since I've totally reassembled an engine.

Thanks for the help!!!
 
Don't sweat it. When I was getting ready to swap in a GM Goodwrench crate 350, I searched up and down this site to make sure I'd have everything covered. LOTS of folks had their dist's 180* out and I was determined that it would NOT happen to me. I checked and double checked and then triple checked. Thought I had it all dialed in. Was sure the motor would fire the first time. As you can probably guess, it did not, cause the dist was, of course, 180* out. I had planned on feeling proud for a job well done, but any feelings of disappointment were quickly erased when the motor fired right up after I fixed the problem.
 
mofugly13 said:
Don't sweat it. When I was getting ready to swap in a GM Goodwrench crate 350, I searched up and down this site to make sure I'd have everything covered. LOTS of folks had their dist's 180* out and I was determined that it would NOT happen to me. I checked and double checked and then triple checked. Thought I had it all dialed in. Was sure the motor would fire the first time. As you can probably guess, it did not, cause the dist was, of course, 180* out. I had planned on feeling proud for a job well done, but any feelings of disappointment were quickly erased when the motor fired right up after I fixed the problem.
Click to expand...

Same here man, I swore up and down I wouldn't get my dizzy in 180 out, but of course, I did, and of course, I called all my buddies over to watch me break it in, lol

Put the dizzy in properly, and she fired right up and hearing those open headers roar, suddenly all my embarassment dissapeared :D
 
LOL i bet 75% of the hands on ck5 crowd has done it. NOt only did i put it 180 out the first time but after i got it timed and running like clockwork i pulled the manifold to rtv the water ports...I broke an intake bolt off in the head, drilled it out then put a good bolt in and torqued it down. I turned it over and it stopped like something was in between the piston and head...never felt more depressed then right that second... Since i had put whiteout on the cap and manifold for the timing i said it couldn't be that its too advanced and dismissed it. one turn of the cap and she fired right up and the rumble of open headers was alive again through my neighborhood.

all my neighbors came out of their houses to see what was making all that noise. :grin:
 
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