timing peoblems

I'm having to worse time getting the timing set and to stay set in Mr 50 Chevy truck it. Has a 307 outa 69 chevelle that was all new built motor when I got it. I have disconnect the vacuum advance and hit the timing mark with a soap stone so I could see it good with the light when I turn the destrubitor to get the mark lined. Up it back fires and dies when I back it off it runs ok until I drive it than back fires when I give it gas I'm thinking maybe a crossed wire any other ideas dose anyone know the firing order for shire on this motor I'm shire its something stupid and I just missing it to many years of exhaust fumes
Thanks psycho sean

1 8 4 3 6 5 7 2
Dist. rotates CW
Drivers side cyls. 1 3 5 7 front to back.
Pass. side cyls. 2 4 6 8 front to back.

If you're running points be sure the dwell / gap is correct. Also, check for slop in the distributor shaft side to side. If there's too much slop the dwell will change walk around and affect the timing.

Also be sure the vacuum source is correct. I've found most of the time it should be manifold vacuum (below the throttle plate.)

Make sure you got a good cap and rotor and it is not arching.

offroadrolls said:

1 8 4 3 6 5 7 2
Dist. rotates CW
Drivers side cyls. 1 3 5 7 front to back.
Pass. side cyls. 2 4 6 8 front to back.

If you're running points be sure the dwell / gap is correct. Also, check for slop in the distributor shaft side to side. If there's too much slop the dwell will change walk around and affect the timing.

Also be sure the vacuum source is correct. I've found most of the time it should be manifold vacuum (below the throttle plate.)

Make sure you got a good cap and rotor and it is not arching.

Click to expand...

THANKS for all the info will be checking first thing in the morning when I get home from work

offroadrolls said:

1 8 4 3 6 5 7 2
Dist. rotates CW
Drivers side cyls. 1 3 5 7 front to back.
Pass. side cyls. 2 4 6 8 front to back.

If you're running points be sure the dwell / gap is correct. Also, check for slop in the distributor shaft side to side. If there's too much slop the dwell will change walk around and affect the timing.

Also be sure the vacuum source is correct. I've found most of the time it should be manifold vacuum (below the throttle plate.)

Make sure you got a good cap and rotor and it is not arching.

Click to expand...

Thanx again firering order was a big help had 3&5 switched don't know how I did it I change wires one at a time but I guess anything is possible at 3 am

I know you found the crossed wires, but .....

Does this 307 have the stock timing chain w/plastic gears? If so, you might want to swap for a double roller with steel gears. The plastic ones have been known to wear/fail.

The balancer may have slipped so the timing mark is incorrect ?

Take #1 plug out and turn the motor over til it gets on comp. stoke and see were the timing mark is on the crank then check the dis. cap an see if its at #1 term.

doggone said:

Take #1 plug out and turn the motor over til it gets on comp. stoke and see were the timing mark is on the crank then check the dis. cap an see if its at #1 term.

Click to expand...

This is how I always start out getting #1 to the top I go from there use a soap stone to make my mark can see it really good with the timing light [ddd

Flipper_1938 said:

I know you found the crossed wires, but .....

Does this 307 have the stock timing chain w/plastic gears? If so, you might want to swap for a double roller with steel gears. The plastic ones have been known to wear/fail.

Click to expand...

Steel gear I hate them plastic coated ones they are nothing but trouble waiting to happen had one fail on a 64 Cadillac I had blowed the new muffler in two when it backfire. I'm thinking of going to noisy gears for timing over the winter I love the sound [ddd