[xchevyguy]

I have just installed a new engine in my 72 LeMans Convertible. The engine was rebuilt a number of years ago and has about 10 miles on it.

I set timing up as per the book turned the key and the motor fired instantly. I let it run till it warmed up turned it off. It refired fine a number of times when hot. (Sure is noisy with open headers!!)

I then let it sit for a few hours and went to show it off to my neighbour. It fired instantly ran for about a minute, backfired and stopped. I have not been able to get it going since. It turns over fine. I have not had time to check anything

I used a lot of used parts that I had laying around so it could be anything. I have power to the coil and did put in a new coil when it owuld not restart and still nothing. (I did not use a resistor but according to the book the wire from the ignition is a resistor wire. (I am not sure what a resistor does in this circuit??)

I have not checked to see if there is any spark at the plugs but the point gap looks ok.

It has an electric fuel pump and a old holly 650 with no choke. There seems to be gas as when I push the accelator gas sprays in. This car has sat for almost 20 years so rust in the tank would not surprise me. The is a filter in the line and the pump turns off so I assume this happens when the pressure is up.

Any thoughts/suggestions whre to start?

Thanks

[xchevyguy]

I have just installed a new engine in my 72 LeMans Convertible. The engine was rebuilt a number of years ago and has about 10 miles on it.

I set timing up as per the book turned the key and the motor fired instantly. I let it run till it warmed up turned it off. It refired fine a number of times when hot. (Sure is noisy with open headers!!)

I then let it sit for a few hours and went to show it off to my neighbour. It fired instantly ran for about a minute, backfired and stopped. I have not been able to get it going since. It turns over fine. I have not had time to check anything

I used a lot of used parts that I had laying around so it could be anything. I have power to the coil and did put in a new coil when it owuld not restart and still nothing. (I did not use a resistor but according to the book the wire from the ignition is a resistor wire. (I am not sure what a resistor does in this circuit??)

I have not checked to see if there is any spark at the plugs but the point gap looks ok.

It has an electric fuel pump and a old holly 650 with no choke. There seems to be gas as when I push the accelator gas sprays in. This car has sat for almost 20 years so rust in the tank would not surprise me. The is a filter in the line and the pump turns off so I assume this happens when the pressure is up.

Any thoughts/suggestions whre to start?

Thanks

[bonneville Joe]

I just went through pretty much the same thing with my 2dr 66 bonneville. Turned out to be my points were burnt. Once I had them set correctly everything now is Kosher. Check them out.

[Brian Baker]

Start with the basics. Check for fire, no fire at the plugs, no go. Then check for fuel. Pull the carb and clean it and replace the fuel filter with one that isn't restrictive. If fire and fuel check out ok, it's time to start looking at something mechanical. Start with a compression check on all cylinders.

[PROBRD]

Pull the distributor and check gear. Hold the rotor with one hand and try to spin the gear on the bottom of the distributor. If it spins the roll pin has broken. That would cause it to backfire and die and not restart.

[Ccass]

moving to Drivetrain-street.