engine compression

[tmaheras]

I brought my 88 560sl to a mechanic because it was misfiring. He told me that the plugs were fouled and asked if it was burning oil and I said it was and that I was planning on having the stem seals replaced in the spring. He then took a compression test and said that 2 of the cylinders on the left side of the engine were low about 78psi and that I should probably pull the engine and do the rings as well. Do bad valves affect engine compression? He said the whole job including timing chain would cost about $4000usd here in Montreal. Any opinions?

[autozen]

Yes, burnt valves can affect compression, however, either the mechanic didn't do a full diagnostic or you aren't relaying all the test results. He should have done a wet test and a CLT (cylinder leakage test) along with the compression test. These tests would have pointed to the failing components. I would not rebuild the whole engine if it isn't necessary. It's like going in for major surgery and having other things removed or worked on just because you are already opened up. I would suggest a second opinion from another shop considering the amount of cash you could be spending for no reason.

Good luck,
Peter