Red Hot 71

I have a 1971 C-3 w/350 motor. Got the thing running great in the last couple of weeks after changing the plugs & wires. Went to start it up this past weekend, it was warming up (cold-blooded) & all of a sudden it just back-fired @ idle & shut off like I shut the key off. Replaced the distributor cap & rotor. Have not been able to start it since. It will turn over & act like it will start, but then backfires & won't. Please help!!! Shows coming up soon.

7t9l82

Lots of possibilities maybe the timing chain jumped

mrvette

MY first guess too, if that is the issue use the Cloyes double roller chain/gearset.....grenade proof....ASSuming they did not go China made.....

Big2Bird

Pull the dizzy cap, all the plugs, and turn thecrank back and forth. See how much slack you have in the chain.

Red Hot 71

Will try that this evening. Hopefully it is that simple. I was not sure if a metal timing chain & gears would stretch that much on a recently re-built motor. But I have read there was a certain time when you could buy nylon gears??? Thanks for the quick responses.

marc9889

I'd also lean toward thinking it was the timing chain, but you might also pull the distributor shaft and check the gear where it meshes with the cam.

Rescue Rogers

you could pull the cap and rotate the distributor forward or backward one postion to see if it did jump before pulling the front off. Also check for TDC on compression to distributor rotor position. I cut the center out of a distributor cap to check this and adjust valves.

I had a 72 F100 that did this when I pulled into a fastfood place years ago. It jumped when I shut it off and would just crank and crank

BLUE1972

I would check the coil and points if you haven't already. I just had the rub block on the points break off on a 67. Same symptoms..

Bring the engine to TDC -top dead center and check the rotor position it will tell you if the chain jumped. Mark the distributor body for the #1 plug , this will make it easier.

CanadaGrant

I would check the coil and the condenser in the distributor.

Red Hot 71

Pointless MSD distributor, box, & coil. I will check ignition out, though. Thanks guys!

marc9889

The purists will object to this recommendation, but I can't help but suggest it. Last week, I pulled my OEM distributor (with Pertronix kit) and Accel coil and installed a $57 EBay HEI distributor. I did a quick timing adjustment based on my vacuum gauge and took it for a test run. What an incredible difference! The car pulls much harder now, and the throttle response is much improved, especially right off idle. Best $60 I ever spent on the car, by far.