Rebuild my 302 HO at home. Started instantly after the rebuild went for a test drive ran well. Sat for a bit as I got busy with work. Tried to get it running again was having fuel issues replaced the fuel pump but still having issues. Now it's just backfiring. Thought I got my timing wrong but I checked again with a piston stop. I heard air, it hit the piston sto, made the mark, backed it all the way until it hit the stop again. Took the difference and it aligned with the original mark I made. Dropped in the distributor but it just cranks, backfires and then doesn't start. Used starter fluid no avail.

New spark plugs, new spark plug wires, new fuel pump. holley 650 cfm 4160 that came with the truck. I've 180'ed the distributor but still nothing. Really not sure what I am doing wrong. Going to try with my timing light when I have an extra pair of hands later today but any ideas?

Here's a picture of the timing marks (3 red arrows). you can see the line on the balancer aligns with the two yellow lines on the distributor (TDC). the one on the blue is the #1 spark plug. the yellow on the metal of the distributor is where the inside rotator is pointed to.

Appreciate the help!

SOLVED: Issue was timing. I heard hissing and assumed I was on compression stroke. Took the valve cover off and I was 180 out. Still having issues with the mechanical fuel pump not sucking any fuel (its new) but I believe they are a bit weak and don't like air. Going to siphon some fuel tomorrow and hopefully it'll stay started long enough to get it tuned in!

 

The rotor?
Those HEI rotors take abuse, short out and throw spark all over
Check the advance weights in that hei for sticking

 

Sounds like a timing issue. I had the same issue with my FE 390. Although they are not the same engine, how you set the distributor is the same. I would say first go back to the basics and make sure your dizzy cap has the correct order of the wires and that they are all going to the correct spark plugs. Once that is confirmed take the spark plug out of the #1 spark plug hole. Disconnect the high tension lead going from the coil to the dizzy cap so it does not try and start up. Stick your finger in the empty #1 spark plug hole in such a way as to seal the combustion chamber. While doing that have a buddy hand crank the engine or if it is just you, use a remote starter to crank it. You will know when you are on the compression stroke when it tries to blow your finger out of the hole. Then take a look at your damper markings and look into the combustion chamber to see if the piston is at TDC when the damper is at TDC. Once you have confirmed this check again where your rotor is pointing. It should be pointing close to the number 1 spark plug high tension lead on the dizzy cap. Adjust/ rotate it if it is not. Once you have this you should be good to atleast get it started at which point you will set the initial timing. If this still does not remedy the issue I would then check the primary and secondary starter/ ignition circuits to confirm you are getting spark. These tests are in my manual for my FE and would likely be the same for your 302.

 

One thing to never go cheap on is the dizzy!

 

Does your distributor have the correct steel gear for the roller camshaft? It takes very little time to destroy a cast cam gear with a roller cam.

 

A long shot but we used to see the vacuum advance spring wear out (on 360/ 390) and full vacuum advance would be all in way too soon
This made the HCs go 2000ppm and a new vacuum advance or a small washer installed in the advance unit to help the spring solved the issue

 

That would be fine but he cant get it to start after it had been running then sat for a bit.

Being nothing would had change from when it was running last as it just sat there, how long did it sit?
I would pull the plugs and do a compression test to see if a valve is hanging up and causing the back fire.
I dont know if I seen it what end is it back firing from carb or tail pipe (true duels?)?
Dave ----

 

Solved it! It was timing. Here's where I was at fault. As I was rotating the motor I heard air hissing. I figured okay I'm near TDC on the compression stroke, however, it was hissing from other cylinders and when I took my valve cover off I realized I was 180 out. Fixed that now I am having issues with fuel! Fuel pump not sucking anything. I believe they need to be primed (I think the mechanical fuel pumps are weak and don't like air) so I ordered a fuel/oil siphon tool tomorrow hopefully I'll get some fuel up to the carb and it'll last enough for me to set the final timing.

Thanks for the advice guys! I just needed to go step by step.

 

You did the right thing going step by step. Now that the ignition is correct you should be able to get it running the old school way with a squirt bottle of gas until the mechanical pump primes itself. Be careful, good luck.

 

Good job crazzmc,
One more thing
If there is a pinhole in the rubber fuel line going back to the gas tank the furl pump will just suck air and not pump fuel

 

Nice! Good job. I replaced my fuel pump. I also upgraded the starter to a high torque mini from powermaster. It cranks just fine now and subsequently the pump pulls gas nicely too.

 

WHAT part number did you buy ??? I want one

 

I did my first ever fuel pump check last fall 2021. I rented the vacuum / pressure gauge from AutoZone and checked a suspicious pump on my 385 series 429. Hmm, the results were 20-inches of Vacuum and 7-inches pressure pushing to the carb ! _ _ I was happy.
Several years ago, I pulled a pump that was not sucking fuel, and once cleaned, the valves worked fine, and it is working today.
That was on my '66 merc FE engine, probably a 390, not sure.

I have found with dual fuel tanks and today's plastic bodied electric tank selector valves, they can suck air from an empty tank.

Glad to hear you were only 180 out on your distributor.

My wife teased me yesterday when I had just fired up a 400M rebuild, and no oil pressure, so shut it down.
As I was about to step out of the cab, my wife says "Don't slip in the puddle of Oil" !!
Yep, I had forgotten the spin on oil filter and the engine pumped a huge puddle of oil (new too) onto the floor.
(I was 180 out)

Ah the joys of Home Mechanic's.