Timing marks are dead on but engine is making noise

[nelaco]

Hi everyone, this morning I went to start my car and it sounded terrible. It had been running great so this just happened suddenly. I thought my timing belt had skipped a tooth so I took the covers off and lined up the crankshaft mark with block mark; I then checked the cams and they are all lined up perfectly.

I removed the spark plugs from the left bank (easier) and they look fine. I also put a magnet inside each of the 3 cylinders and nothing came out. The car has 183000 miles and I replaced the timing belt at 111000. I am out of ideas. I'll remove the right side spark plugs just in case, and do a compression test on all 6 cylinders, but can anyone think of anything else I could do to figure out what the problem is? I was hoping to pass on this car to my 16 y/o son. Appreciate any help you can give me.

Pete

'92 929

[older929]

What kind of noise? metal on metal? Does it sound internal to the engine or external? Might be just a failed auxillary belt tensioner. Are you getting a steady rap-rap-rap-rap type noise? I had the hydraulic tensioner fail on my engine and it let the tensioner wheel hit against the block. Sounded terrible but was an easy fix (well, timing belt job again, but only a new tensioner). Any smoke?

[nelaco]

Thank you for trying to help. The sound was really loud...like lifters. I tried running the engine like that a couple of times for a few seconds hoping that they would free up but it didn't help. After removing the timing covers and realizing the timing was correct I proceeded to take a compression test. Two of the 6 cylinders were terrible...they would barely build pressure...around 70psi. The rest were more like 220 (cold engine). I decided to give it one more round of testing just in case I hadn't screwed the tool properly. This time all the numbers were about the same at 220! Obviously the lifters giving me the problem became free and the problem went away. When this happened I hadn't used the car in a few days so from now on I am planning to start the car at least every other day to avoid the lifters from getting stuck again. Does anyone know of a good oil additive for this? I do change the oil every 3000 to 5000 miles and I have been doing this since I got it with 19k miles 10 years ago. Thank you again for your help.