Re: Backfiring vs Timing

Posted by Jack Richard on September 07, 1997 at 11:22:13

In Reply to: Backfiring vs Timing
posted by Walter Cruden on September 06, 1997 at 21:52:37

: Enjoyed a ride to the post office in a friend's Model A except it backfired and had no power to climb hill.He was not adjusting the spark manually for changing conditions but even when he did he still experienced the backfire out the exhaust.We followed the "instruction book" manually locating the dimple on the front gear through the timining hole.The distributor rotor pointed to the number one contact and the manual spark advance was fully retarded.But using a pencil through the spark plug opening indicated that the piston was down, not fully up.So the cylinder would fire when the piston was down rather that starting down or ATDC.To me that says that the timing chain or timing gear is not properly aligned between the crank shaft and the valve cam shaft.I base this on working with modern cars.Is the analysis true also for a Model A?I can't give any more details because he wanted to stop and eat diner, so we closed it up.
The most common reason for the problem you describe is a bad condensor.Try replacing it with a known good one before going to great lengths with other "cures".
Good luck - let me know what your friend discovers!

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