I did some routine maintenance this weekend; oil/filter change, tire rotation, and spark plugs. I wanted to do a compression test on the cylinders just to check them so I purchased a compression tester on Amazon recently. I had also purchased a wireless borescope on Amazon prior to this with the intention of scoping my intake valves at some point but then figured I'd scope the cylinders as well since I'm changing plugs.
The compression test went well. I did some research on the procedure and basically followed the How To guide published by Stratifed, found here.
Tools
Innova 3613 OHC Compression Tester
KYZEE Wireless Endoscope
Environmental Factors
Elevation - 900 ft. above sea level
Temperature - 85 F
Humidity - 45%
Pressure - 29.94 inHg
Engine
Mileage - 110,000
Oil change interval - every 5,000 miles
Oil - Motorcraft 5W-20 Synthetic Blend
Oil filter - Motorcraft FL400S
Gasoline - 91 (winter) / E30 (summer)
Spark plug change interval - every 20,000 miles
Oil catch can - installed at 30,000 miles
Procedure
I made sure the engine was warmed up from normal driving. After 10 minutes with the engine off, I started by removing all four coil packs and spark plugs. I started the compression test on cylinder #1 (closest to timing belt). My expected pressure for each cylinder was roughly 147 psi. That pressure is based on multiplying the engine compression ratio (10:1) by atmospheric pressure (14.7 psi). My location is 900 ft. above sea level so technically atmospheric pressure should be 14.4 psi but then you can also factor in ambient temperature. I'm not trying to be that technical, I just want to make sure all 4 cylinders are reading within 10% of each other. The other factor is my equipment but it seemed to be holding pressure just fine based on the initial testing I performed.
With the clutch and gas pedal fully depressed, I pressed the engine start button once and let the engine crank until it was done (roughly 23 revolutions/cranks). This may be overkill for the procedure but I wasn't going to try and stop the engine cranking and get arbitrary results if I didn't stop the crank cycle at the same point every time for each cylinder. For the first test I used the included 8" extension that came with the kit and my first reading was 110 psi. I thought that was low so I made sure everything was tight and cranked the engine over again. I was still only getting 110 psi. I removed the extension and cranked the engine again, this time I reached 180 psi which seemed better to me so I continued the test without the 8" extension from the kit.
Compression Test Results
Cylinder #1 - 180 psi
Cylinder #2 - 180 psi
Cylinder #3 - 180 psi
Cylinder #4 - 176 psi
Cylinder Borescope Inspection
The bore scope has somewhat of a fisheye effect so the pictures might look a little distorted/stretched. I basically wanted to look for carbon build up, cylinder wall damage, piston damage, etc. I snapped a pic for the back side and front side of the piston. For picture reference, front side indicates the side that faces the front of the vehicle.
The compression test went well. I did some research on the procedure and basically followed the How To guide published by Stratifed, found here.
Tools
Innova 3613 OHC Compression Tester
KYZEE Wireless Endoscope
Environmental Factors
Elevation - 900 ft. above sea level
Temperature - 85 F
Humidity - 45%
Pressure - 29.94 inHg
Engine
Mileage - 110,000
Oil change interval - every 5,000 miles
Oil - Motorcraft 5W-20 Synthetic Blend
Oil filter - Motorcraft FL400S
Gasoline - 91 (winter) / E30 (summer)
Spark plug change interval - every 20,000 miles
Oil catch can - installed at 30,000 miles
Procedure
I made sure the engine was warmed up from normal driving. After 10 minutes with the engine off, I started by removing all four coil packs and spark plugs. I started the compression test on cylinder #1 (closest to timing belt). My expected pressure for each cylinder was roughly 147 psi. That pressure is based on multiplying the engine compression ratio (10:1) by atmospheric pressure (14.7 psi). My location is 900 ft. above sea level so technically atmospheric pressure should be 14.4 psi but then you can also factor in ambient temperature. I'm not trying to be that technical, I just want to make sure all 4 cylinders are reading within 10% of each other. The other factor is my equipment but it seemed to be holding pressure just fine based on the initial testing I performed.
With the clutch and gas pedal fully depressed, I pressed the engine start button once and let the engine crank until it was done (roughly 23 revolutions/cranks). This may be overkill for the procedure but I wasn't going to try and stop the engine cranking and get arbitrary results if I didn't stop the crank cycle at the same point every time for each cylinder. For the first test I used the included 8" extension that came with the kit and my first reading was 110 psi. I thought that was low so I made sure everything was tight and cranked the engine over again. I was still only getting 110 psi. I removed the extension and cranked the engine again, this time I reached 180 psi which seemed better to me so I continued the test without the 8" extension from the kit.
Compression Test Results
Cylinder #1 - 180 psi
Cylinder #2 - 180 psi
Cylinder #3 - 180 psi
Cylinder #4 - 176 psi
Cylinder Borescope Inspection
The bore scope has somewhat of a fisheye effect so the pictures might look a little distorted/stretched. I basically wanted to look for carbon build up, cylinder wall damage, piston damage, etc. I snapped a pic for the back side and front side of the piston. For picture reference, front side indicates the side that faces the front of the vehicle.
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