My son picked up a model a coupe with 4 banger, mallory single point distributor, Carter carb, Burns intake. Motor was said to have been rebuilt but car was partly dis***embled when he bought it and spent time getting other mechanicals taken car of. His plan was to run as is and save for future upgrades. We got the motor fired up but has a noticeable misfire at idle. When choked and rev'd the car seems to run ok. Checked firing order, timing, new points, condenser, plugs,wires and then pulled the carb apart, cleaned and inspected. No change. Pulled number 4 plug wire and popping stopped. (but obviously running on 3 cyl). Swap Another plug pop stayed with cylinder 4. swapped plug wire and pop stayed with cylinder 4. Compression checked and #3 cylinder slightly lower but still within range with other cylinders. Head gasket? Any suggestions on next steps before we have to pull head? Any help appreciated.
If it's a sticking valve get a quart of Rislone oil treatment and pour it in the crankcase. Start driving the car and it will slowly free itself up and the compression in that cylinder will return and the miss will go away. The Rislone can be taken out at the next oil change. Frank
thanks Fab... valves look to be moving free... flash light in the cyl and they look to be opening and closing. Motor sat for a while, How common are stuck rings? -Jesse Zippers son.
My experience is that stuck rings will pressurize the crankcase. You can tell if you remove the oil filler breather. It will puff out the breather, not miss and pop. Check and make sure that you have the same dwell, or point gap on each lobe of the distributor cam. One not opening as much as the others will act like I understand what you are describing. Let us know. LJ
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