I just replaced the heads on my 1973 F-100 390, and now I can't get it to start at all. I had the timing chain cover off when I was waiting on the new heads, and the timing marks on the gears lined up, so it shouldn't be a problem in the timing chain. When I re-assembled the motor, I triple-checked the torque on everything, and I put all-new plugs and wires, etc. on it. I hand-cranked the motor to TDC, and made sure I had the distibutor in place with the rotor pointed at #1. I double-checked the firing order, and it is getting fuel, and spark. cranking it over with the timing light on it, it lights up at 6 deg. BTDC when the #1 plug fires. From what I understand, it should start, but it won't. Playing with the distributor's position doesn't solve the problem. While toying with the dist. position, it has backfired out the pipes twice, and has backfired through the carb a couple times. The rest of the time, it sputters(not backfires) out the carb, but refuses to start.

What do I do? I wouldn't think it's a vacuum problem, since I have the PCV and vacuum advance routed correctly and the rest are plugged off. It's not the firing order, because I have double checked that. All the plugs appear to be firing, I pulled them all and tested them for spark. it's getting fuel, you can see and smell it in the carb. I'm at my wit's end trying to figure this one out. Please help?

 

The distributer is off 180*, very easy to do.

For every ONE time the distributer goes around, the crankshaft goes around TWICE. Intake, compression, power, exhaust...

The piston is at the top of it's travel at the end of the intake and exhaust strokes. You have the distributer installed on the exhaust stroke. Remove the #1 plug and put your finger over the hole, turn the engine and you'll feel the compression stroke. Stop on the compression stroke, turn the balancer to TDC and re-index the distributer to #1 terminal.

 

I'll be... I feel like an idiot now, LOL

I did that, and she fired off perfect the first time... and on top of that, the timing didn't have to be adjusted at all after it was running.

Thank you so much! If you're ever in oklahoma, I owe you a beer.

 

Happens to us all, but always humbles a person.

 

Nice call Hypoid..I never have that problem myself but am working on dropping the oil pump drive shaft in the pan a 3rd time

 

LOL, UHH GORSH!!! How do ya think I got all that "practice, practice, practice"??? :~P

Yeah Josh, I could say welcome to the club, but it's not really that exclusive. LOL

 

It happens to me about 1/4 time, I guess I'm a bit lucky.
It really hard to tell if the engine is in the compression stroke or exhaust relief stroke, without popping the valve covers and checking. In other words, when it happens, it time to rotate the distributor 180 degrees as Hypoid mention.

I installed a locking washer on distributor shaft to eliminate the distributor shaft from falling in to oil pan, during assembly, it came with the arp distributor rod shaft, the washer eliminates the distributor shaft from falling in pan.

 

I've dropped the oil pump shaft twice in the same day. That little lock washer is very important to me now. Glad you got your truck straightened out quickly.