I found a beautiful 1980 242 with no rust and totally solid for 500$ in a guys barn. After throwing a new battery and doing a little tune up I drove the car home. Suspension is tight and 4 speed shifts smoothly. It had a real rough idle I got smoothed out, but it still isn't running great. I haven't done a compression test but the is oil all over the block and I get varied results pulling the plug wires. Plug 1 and 3 respond pretty normally and affect the idle. Pulling plug 2 kills the motor and pulling plug 4 does nothing. There is spark but the idle is not affected. I'm debating whether I need to replace the head gasket or overhaul the engine. Ive never taken a motor apart but I'm not to scared of the b21. It is a very straight forward motor and with no ac or power steering, there is plenty of room to work with. Does anyone have any tips on diagnosing where the compression issue stems from and what to look forward to with an.overhaul? Can I replace the piston rings without removing the engine from the.car? Thanks for any advice! The car has plenty of power though and can get up and go in all gears



Oh on a side note all the dash light are always on but flicker when I accelerate. Does this sound alternator related?

 

Your new car is mechanical injection. Bullet proof but does not like sitting up for great lengths of time. Before I tore into the engine, I would perform a genuine compression test, both dry and wet if needed.
Theoretically, you can replace rings while the motor is in the car by loosening engine mounts, hoisting motor, pulling oil pan, and then pulling the pistons through the top. Honestly, sounds like a real pita. If you re-ring, you might as well replace the con rod and main bearings. They are the source of your oil pressure, you know. Cut corners on the bottom end and the head will pay for it.

 

Yeah actually after pulling the injectors and cleaning them really well, cylinder 4 started firing. Still getting a compression test done though.