Hello,

As I am anxiously awaiting my appt. with the doctor, I am curious to see if any one here has had a loss in compression - 1 cylinder and conducted a wet compression test. (A wet compression test is dabbing in a small amount of oil into the top of the cylinder through the spark plug hole.) In my case, the wet compression test resulted in my psi jumping up from 180 to 210. 210 is pretty much what I had on the other 3 cylinders. The cylinder in question is # 3.

What were the results ? Ex. a damaged head - bent or burned valves or damage to the block - rings or walls scored.

 

Most likely damaged bottom end...the oil added helps fill the poor contact between the worn piston rings and cylinder walls which results in a increase of compression psi. A burnt valve could care less if you added any amount of oil to the cylinder.

 

"Bottom end" being the compression rings? When I think bottom end, I think crankshaft.

 

Yes, bottom end meaning the block. Which could be either piston rings and/or cylinder walls

 

Under normal circumstances the cylinder walls will easily outlast the cylinder rings. The number one thing that damages the cylinder walls is a broken spark plug piece bouncing around in the cylinder, or a broken valve less likely but possible is if something gets dropped inside the cylinder with the plug out, or running without an air filter for extended periods in dusty conditions. Otherwise it's usually the rings, particularly the top ring. Also possible but highly unlikely is a stuck cylinder ring from neglect.

 

The beauty is this car is maintained like no tomorrow. I am the type of guy to change plugs every 2 seasons just cause. Oil/filter is changed at no more than 2500 intervals usually less. My air filter is a K&N cone inside the OEM airbox.

Not gonna beat the case up until the car is fully inspected. Looking to do another compression test, leak down test, use a borescope to inspect the block and of course inspect the valves for damage and current lash settings.

 

Hopefully this isn't a case of good intentions gone wrong. You change plugs too often IMO.

Number one cause of scored walls is broken plug, number one cause of broken plug has to be loose plug. Do you follow the updated torque specs for the plugs? Billman recommends even tighter than that, 24 ft/lbs IIRC.

The plug threads in head are aluminum. Do you make sure to change plugs when engine is dead cold?

I would try to keep wear on those threads to a minimum. Plugs easily last 75k miles or more. Changing them every two years is not benefitting anything.

 

Bill did the plugs both times, both with the recommended increased torque.

 

Also doing a Blackstone Oil analysis to look at the oil closer.

 

How long have you owned the car for?