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how to start a 302

samson101478

Jr. Member
Joined
Jul 23, 2013
Messages
266
Loc.
corfu
trying to start my 302 in the bronco im building. building it from scratch. i just had the engine built and put in. i have not installed the new harness yet. i want to start the engine so bad. i always thought if i supply the coil with power and apply juice to the starter it should run. well i am cranking it over but will not start and the wire going to coil gets really hot. what am i missing?
 

dave67fd

Bronco Guru
Joined
Sep 24, 2010
Messages
2,863
Confirm your basic wiring setup. Was the motor pre-run or setup (points, timing, carb)?
The negitive terminal (-) goes to the distributor wire.
 

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samson101478

Jr. Member
Joined
Jul 23, 2013
Messages
266
Loc.
corfu
i will wire in a temporary key switch using the one from the sentec system and wire it up just like that diagram . hopefully it will fire up. still not sure why the wire gets super hot. ill wire it up and see. thanks for the help and will keep you posted
 

PaveBronco

Sr. Member
Joined
Oct 30, 2012
Messages
912
Do you have a resistor in the system between the key (power) and the coil ?
 

WheelHorse

Bronco Guru
Joined
Nov 22, 2004
Messages
2,492
Has your engine already been broken in on a dyno?

IF it's roller cam, the break in is no where near as nail biting as a flat tappet.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
48,964
What dave and WheelHorse said. And don't just sit there cranking it if it is not starting right up. Prime the oil system, prime the fuel system with some gas in the carburetor's float bowl, check all your bolts and nuts and anything you can think of. Even to the point of checking your ignition manually for spark.
If you don't, your anxiousness for starting it up to hear it run could wipe out all of your investment in one fell swoop when you wipe out your flat tappet cam.

Sorry if you have a roller, but we wanted to make sure you were familiar with how critical the initial startup is with a flat-tappet cam.

Good luck. It's always exciting to hear it run for the first time!

Paul
 
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samson101478

Jr. Member
Joined
Jul 23, 2013
Messages
266
Loc.
corfu
Wow i have a lot of responses . You guys are awesome. I primed the oil , it does have a resister. Spark at the plug And gas. It cranks over fine and just pops and farts. Timing is right on the money and according to the manuel I have the firing order right. I think its weird that the coil wire gets hot fast. I didn't have time today to wire in a ignition switch. Hopefully tomorrow. I wonder if the resister is bad
 

Socal Tom

Bronco Guru
Joined
Feb 12, 2004
Messages
2,442
Loc.
San Diego, CA
Popping and farting is a sign of the dizzy being 180 out. The easy way to check s to swap the wires across the other side of the cap.
Tom
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
35,524
There are two different top dead centers. One on the top of the compression stroke, spark here and the engine will run. The other is at the top of the exhaust stroke, this makes for popping and sneezing backfirey no run.

Also check the firing order carefully, check it against the cam card as well. There are two different firing orders possible depending on what cam you have.
 
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samson101478

Jr. Member
Joined
Jul 23, 2013
Messages
266
Loc.
corfu
If its not the stock firing order then what is the other firing order? I believe I had a comp cam put in to match the comp cam roller rockers in it. The guy I had build it moved down south. So I can't ask him the details that I have forgotten about. He did break it in for me so I know its good to go .how ever I pulled the cap of and changed wires .I put them back to what the book said.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
35,524
The original small block firing order is 1-5-4-2-6-3-7-8
But the 351 and 5.0 HO (most of the mustang roller cams) have the firing order of 1-3-7-2-6-5-4-8

This is dictated by the cam, the crank has the same throws. Basically half the cylinders have the firing and compression strokes swapped.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
48,964
No guessing on this. 'Gotta take a few plugs out and verify with a finger tip over the plug hole while you or someone rotates the crank clockwise.
You may have to turn it over several times just to make sure what you're feeling is really the higher pressure of TDC on the compression stroke.

1. When you start to feel the big buildup on the #1 cylinder, watch the markings for TDC that should be coming up (we're assuming that the damper is the correct one and the markings are accurate) into view.

2. With the #1 cylinder at TDC, verify where your distributor rotor is pointing. If at #1 wire, great. If not, pull and re-install correctly.

3. When the timing marks are at TDC for #1, you should put a finger on #3 and/or #5 (if you have two people or a long reach) to see which cylinder pressurizes next.
It should be within the next quarter turn or 90° of crank rotation.

Whichever one is next will determine your firing order. Verify your #1 wire position and orient the rest in a counter-clockwise direction for your cam.
And just to be sure (because it happens a lot) you are familiar with the Ford cylinder orientation? With #1 being the front-left when facing the engine. Or front passenger side.
From there it goes 1, 2, 3, 4 all on the passenger side. 5, 6, 7, 8 are front to back on the driver's side.

Just thought I'd throw that out there as many owners are more familiar with GM or Dodge and everybody likes to do it different.

Paul
 
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samson101478

Jr. Member
Joined
Jul 23, 2013
Messages
266
Loc.
corfu
Ok I temporary wired in a ignition switch. Properly ran the wires. Tried the ho firing order and even did the 180 degree.firing order. I get the most reaction at regular 302 order. No start! Think I might be fludding it. Ill try some more tomorrow.thanks everyone for the help.
 
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samson101478

Jr. Member
Joined
Jul 23, 2013
Messages
266
Loc.
corfu
Just so everyone knows. The engine ran at the builders shop. I pulled all the wires off and put a new carb on it once i put it back in the bronco.
 
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