ThamesCruiser
New member
I've just had my engine rebuilt and it's not yet run-in. The block was replaced due to corrosion on the top surface. The head skimmed and valves reseated (I hope!). Several quality issues with the guys that did the job and two weeks ago I had to buy an 'insert' for the oil cooler (oil leak into the bilges and sea). I bought them the insert and a complete set of oil seals.
That done - we went out and when we got back the idle speed was lower and running lumpy. I decided to do a hot compression test (a few days later) and when I'd removed all the plugs and opened the throttles I heard a loud crack. Starter turned over OK and twice more heard the same cracking sound. The results were all above 160 and within 10%.
When I put the plugs back in to make sure it would start again once more a crack but it then started several times more without happening again.
Next day I went to do a cold test (number 4 was lower than the others and I thought I'd do them in reverse order with a fresh battery) and the oil was now emulsified! No oil leak into the bilges this time but I suspect into the marina - even though it was run / turned over since I saw the milky oil). Could the crack have been the exhaust manifold? Cylinder head gasket? The head itself?
Someone (different company) will flush out the seawater / oil this week (she's back on her trailer) but they're fully booked for a few weeks so the cause will not be investigated very soon - unfortunately. Your thoughts and suggestions will be gratefully received, thanks.
That done - we went out and when we got back the idle speed was lower and running lumpy. I decided to do a hot compression test (a few days later) and when I'd removed all the plugs and opened the throttles I heard a loud crack. Starter turned over OK and twice more heard the same cracking sound. The results were all above 160 and within 10%.
When I put the plugs back in to make sure it would start again once more a crack but it then started several times more without happening again.
Next day I went to do a cold test (number 4 was lower than the others and I thought I'd do them in reverse order with a fresh battery) and the oil was now emulsified! No oil leak into the bilges this time but I suspect into the marina - even though it was run / turned over since I saw the milky oil). Could the crack have been the exhaust manifold? Cylinder head gasket? The head itself?
Someone (different company) will flush out the seawater / oil this week (she's back on her trailer) but they're fully booked for a few weeks so the cause will not be investigated very soon - unfortunately. Your thoughts and suggestions will be gratefully received, thanks.