1988 454 crusaders

"Hello all , i'm new to th

"Hello all , i'm new to this board. I own a 1988 mainship mediterranean with 454 crusaders .I only have 220 origional hours and own the boat for 8 years. 2 weeks ago while getting ready to store the boat for the winter i decided to take it out for one last spin. All was well and as i started to head back in i felt my port engines rpms drop . I throttled back and continued in thinking all was ok. When i docked the boat and went down below i could hear a loud knock comin g from the engine. I tried to see what it could be but saw nothing. Checked my belts , hoses pulleys and listened. No drop in oil pressure and no rise in engine temp.Any ideas because i think it's going to be a long cold new york winter."

"I don't know, but a compr

"I don't know, but a compression test will probably answer a bunch of questions.

Check the engine oil and the trans fluid, look for proper levels and metal traces in the fluids.

Good luck
Rick"

"Thanks, rick i plan on trying

"Thanks, rick i plan on trying that . what should compression be?"

"Don't know the specs, but

"Don't know the specs, but i would look for readings that are north of 130lbs... but more importantly - consistent among cylinders."

don't forget to warm them

don't forget to warm them up before the test

"I recently found out that bac

"I recently found out that back in 1997, GM revised their recommended procedure for performing compression testing. In essence, it is the old procedure without the warmup cycle. In doing this, they set the minimally acceptable level, for any reading to 100 psi.

They also provided a new window for variation: Min reading at least 70% of Max reading. Practically, this means if your readings are between 100 and 143 PSI, cold, you are acceptable."

"If, in fact, you have actual

"If, in fact, you have actual internal engine knocking, don't put all your faith in the compression test. A learned ear is much better. If this knocking is not an accessory or a valve train related knock, plan on a pullout and a teardown.
Is it a knock, or a tick, whine, click? Is it always there, or dependant on engine rpm, or only during acceleration, etc."