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Old 06-08-2010, 01:30 AM
240dddd 240dddd is offline
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Join Date: Aug 2009
Location: Seattle
Posts: 476
help deciphering compression test

I ran a compression test this evening on my 78 240d. I did this because I mysteriously leaked a bunch of oil last week and I thought my engine was producing a lot of blowby. I decided to invest in a compression tester and find out how healthy the compression is before I put more time into the car.

Anyhow, this is what I came up with (first number is how high compression jumped after first crank, second number is where it topped out after 10 cranks)

  1. 175/305
  2. 200/375
  3. 200/380
  4. 200/375
My understanding is that these numbers are not horrible, however I am concerned that cylinder 1 is markedly lower than the rest.

Can anyone offer feedback on what I should think about these results? Any advice on what I should do about cylinder one being lower than the rest.

Also, I should mention that when pulling the injectors cylinder one was very dry while cylinder 4's pre-chamber seemed wet and oily. I would have expected the opposite considering the test results.

Thanks.
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