I have a 1977 Chrysler 55 HP, magna power 2, with low compression in one of my cylinders. How can I tell if it is a ring problem or a blown head gasket or possible something else?
Add a squirt of TCW-3 (grade outboard motor oil) and see if the compression improves. If its a stuck ring the TCW-3 will work it loose and an improvement in compression will occur. If it doesn't improve it could be a head gasket or "something else".
Simply pull the head and inspect the gasket, cylinder, and piston for damage. If the piston and cylinder look good you can pull the port cover on the side of the motor to inspect a little further. If the gasket is good, cylinder looks good, piston has no visible damage, then you may have stuck rings. If this is the case, remove the piston and carefully free the rings. Clean it up and re-install, check compression again.
