Re: 1938 Super 8 1605 - adventures with a newbie

Posted by TxGoat On 2023/10/22 8:57:58

The flashes will change speed and timing may be affected if the engine speed is not steady. You can check valve action with a compression test, which I would suggest you do. Compression pressure readings should be within 10% from lowest to highest. It's possible the timing light is not working correctly. The distributor shaft bushings can wear enough to allow the shaft to wobble slightly, which causes the point gap to change enough to affect timing. The shaft that the rotor attaches to should move freely with no discernable side play. A problem with the mechanical advance unit could cause the same problem. Broken or weak springs in the mechanical advance unit could cause erratic timing. * I'd double check the plug wires to make sure they are all seated correctly and in the correct firing order. It's easy to mix them up.

I believe the initial timing should be set at 5 to 7 degrees before TDC with the engine idling smoothly at about 500 RPM. At a faster idle or with a rough idle, it may be difficult to set the timing correctly since the mechanical advance may be coming into play or slack in the timing chain could cause erratic timing.