350 - Cranking, won't fire

[1987 GMC Jimmy]

I have trouble seeing it looking down, but I’ll use the phone video camera with the light on without receding and just point the lens down into the carburetor and watch the screen while I work the throttle.

 

[Bigalturk1]

Verified spark with a timing light on cyl 1.

I can smell fuel in the carb, but I don't see any fuel being sprayed when pumping the throttle cable.

Getting a pop out of the exhaust now after further cranking.

Hey guys,

Trying to get my truck running today.

New build, but I can't get it to fire. It's cranking easily, but just won't fire. Has a small pop with a bit of smoke, but I can't tell if it's coming from the carb or from the exhaust since it's headers to muffler to tip right about the transfer case.

Build:

SBC 350 .030" over
Hypereutectic Pistons
76cc Smogger heads
HEI Distributor
Mild Comp Cam
Stock 1.5:1 rockers
Mechanical Fuel Pump
Quadrajet 4-bbl Carb.

All help is appreciated.

 

[Bigalturk1]

Most of the time I've see people install the distributor 180 degrees-OFF.

 

[WHEELMAN]

You could have the distributor out.the rotor button has to point to number one plug.on the compression stroke.make sure all wiring is tight.wires on the starter too.you can ground the end of a plug on the exhaust manifold.to see if it is firing.see if a plug is wet with gas.

 

[eskimomann209]

Purple wire on the steering shaft get knocked off? What is it the nss

 

[theblindchicken]

Actually having some rain here in California for once. Been going since Friday, and gonna last until Wednesday/Thursday-ish. So gotta wait until the rain's all gone to get anything done.

Definitely sounds like you all agree its 180 out, and so did my dad too. I'll have to get someone to help me out with watching the valves as I rotate the crank since its a bit hard to watch with the core support in the way.

So hopefully have the truck firing this weekend, then hop on the reassembly and get her road worthy by the following week or two. It's been too long since she's been driven.

 

[Rusty Nail]

 

[Rusty Nail]

Purple wire on the steering shaft get knocked off? What is it the nss

Good idea!
If that were the case, I don't believe it would crank. Dash lights would work and other power would be present, but no starter solenoid?

I may be wrong...

 

[theblindchicken]

Purple wire on the steering shaft get knocked off? What is it the nss

Just rebuilt the steering column as well since the old shift tube broke at the plastic bits.

Whats an nss?

She spins great with the heavier starter and a new battery, but just wasn't firing.

 

[Rusty Nail]

Neutral Safety Switch

The purple wire is the one you add a kill switch to.

*or a spade-type fuse holder

 

[Jerry phillion]

First thing I would do is rotate engine TDC. Next, pull drive"r
Valve cover. #1 cylinder should have both valves closed. If
Not, rotate engine 1 more time back to TDC. Both valves
Should now be closed. If neither is right, your cam is not installed
Right. But, if #1 cyl is located right, pull dist cap and see if
rotor is pointing to #1 plug wire. If not, you can do 1 of 2
things. Either lift dist and turn rotor to line up with plug
wire, or put #1 plug wire in cap at that position and replace
Rest of wires in proper firing order.

• Chevrolet (9)
• Dodge (2)
• Ford (1)ire

 

[Snoots]

Or, if you don't want to pull the valve cover, pull the #1 plug, disconnect the power to the distributor and have someone bump the starter while you have your finger in the spark plug hole.
When it blows your finger out, you're very close to TDC. Usually you're just a degree or 2 past but that gets you close enough.

 

[eskimomann209]

Wire for 12v on the dizzy hooked up and supplying voltage?

 

[73c20jim]

How long since it last ran??? Bad gas???

Remote chance plugs are fuel fowled.

 

[theblindchicken]

How long since it last ran??? Bad gas???

Remote chance plugs are fuel fowled.

Completely new rebuild and block (original was a 1974 010 block, new one is a 1986 036 block), so haven't had the truck running since about April 2017 with initial teardown.

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Some parts weren't actually used (valves, valve seals, valve springs springs) as these were reused/reconditioned or included when the heads were rebuilt by local shop.

The rain is supposed to subside tonight, so hopefully get the engine fired tomorrow or saturday before my night shifts.