With the brakes working, we began wondering why the engine ran so poorly. By poorly I mean an idle of over 3,000 RPM and a pronounced miss.
The first place to start was compression. Below is Daniel holding the Harbor Freight compression gauge in one of the spark plug holes while I cranked the engine.
We found two results of note:
- According to the Sears engine tuneup meter on the right, the engine idles at 2,000 RPM, still way too high, but not 3,000 RPM. It appears that the car’s dashboard tachometer is way off.
- Cylinders 1,3, and 4 all have compression readings around 150 psi. This is very good news. Unfortunately, cylinder #2’s compression is 120 psi, sufficiently below the other pressure readings to be of concern. Low compression points to ring or valve problems. Either the air/fuel mixture is leaking by the rings when the piston is compressing the mixture or it is leaking past one of the valves.
Sunbeam 