Hi My 4.7 ghibli engine was completely stripped, cleaned and rebuilt last year. I've now completed the running in and covered 1000 miles. We ran a compression test and 4 cylinders were around 150-160 and 4 were around 120. Not a great result and the question I have is will this get better as the engine is run in more or is it more likely that the rebuild was done badly. I haven't done a leak test but I assume this will tell me more about the issue ? Many thanks for any advice Mike
Hi, Are they all low on one head and high on the other? Could be cam timing is out. I have a similar result, all around 155 one side and 140 on the other Julian
Hi, I'm not the expert but I read on line that ideally the top and bottom values should be within 10% ideally and within 15% max. So yours look a bit off at the moment. Hopefully the others here can help a bit more than me Julian
Try doing a wet compression test by squirting some oil down the cylinder just before testing each cylinder. Some increase in the numbers is to be expected. A very large increase would indicate faulty rings. A small increase would point to the valves. Perhaps the valve clearances are too tight. Ivan
