Took the RS into Russ' Garage today and did a compression test on the EJ25... with not so fun results. Evidence of trouble was already afoot when the spark plugs were removed (we were replacing them anyways). Spark Plugs #1 thru #3 were coated in white ash, a sign of the car running rich, which I already expected. It's #4 that has me worried, which is pictured to the left.
Essentially, the results showed almost no compression for our friend #4. There's also a gasoline smell in the oil. It's still burning it's way through that oil, too. Cyl #4 is expressing an extraordinary amount of leakage into what sounds to be the crank case. Could be piston rings. Could be intake or exhaust valves. Because the sound during the compression test was in the case, out of the oil filler neck, not out of the exhaust pipe, there's more evidence pointing towards ringlands.
We could check the valve "lash" or clearance and see if the valve train is hanging up on that side. However, the condition of the Spark Plug in Cyl 4 leads us back to ringlands.
When I decided to tackle this car, I was alright with the condition of the body and interior, the mismatched wheels, the missing exhaust, the shot suspension on the RS. All I was really banking on was the motor and transmission being alright. It's not a death certificate by any means, just a little frustrating at first. It's another speed bump, but it's also another great set of stuff I'm learning on this car. Still makes it fun and the results of the work put into it are enjoyable.