Hello I am trying to get a doner engine running and swap it into my 300 SD. The car was in an accident and had heavy front end damage with 200,000 showing on odometer so I assumed ran ok up until accident. How many yrs. it sat I do not know but all the brakes were rusted fast when I trailered it home. Must have sat 20-25 yrs. Well I had hopes to get this engine running but not sure if I should waste any more time at the moment as the compression numbers looked very bleak they were #1 cyl. (200) #2 (240) #3 (200) #4 (100) and #5 (380) wish they all were like 5 any way this check was taken after a valve adj. on cold engine never got it running yet. Why would #4 be so low? I will try to start the car tomorrow but with those low numbers do not know if I will succeed. Should I waste any more time on this engine or move on to another? Could this engine just maybe need a valve Job to make it a good running engine?