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Engine background/ discussion for diagnostic and evaluation purposes.
1. The Correct Craft boat engine (454 “reverse rotation”) started missing badly while in use and lost power. Lifters were collapsed and clattering. (The engine was reportedly “rebuilt” a year earlier by a prior owner’s mechanic, but there is no documentation of how extensive this rebuild was.)
2. Investigation as to cause revealed that is was being operated with quite a lot of rainwater accumulation present in the bilge. The oil pan was definitely well into the bilgewater depth in this “V-hulled” boat.
3. The bilge-water also had a large amount of engine oil in it. A real mess!
4. Checking of the engine oil by dipstick revealed that it was very low, and what oil remained in the engine was badly contaminated with water.
5. I changed the oil, and restarted engine (at idle on the trailer at the boat ramp). Clattering lifters remained and engine ran poorly. I added a GUNK brand engine oil additive to try to free the lifters, and idled for another 15 minutes without success. Lifters were still collapsed and clattering, and the engine ran poorly.
6. I took the boat back to our house and removed all spark plugs and performed a compression test twice on each cylinder, (looking for possible leaking head gasket). Compression not great, generally around 125 psi, but no “low” compression on side by side cylinders, leading me to believe that head gasket was not the root cause (recognizing that a gasket could possibly fail between oil and water passages, but remain intact between cylinders---possible, but unlikely).
7. I am puzzled because I cannot see any source of oil leaking into the bilge (i.e. looking for “cracked’ engine block) The intake manifold has not yet been removed to look for crack in the intake manifold “valley” area. A crack in this area would allow water to get into the engine oil, but I don’t see how engine oil could get into the bilge, so I am reasoning that this is not the situation. Similarly, a rusted out exhaust manifold or riser might allow water into the cylinder(s), and some amount s could conceivably get into the oil, but I don’t think oil could get into the bilge from that point, so again I am dismissing that as a probable cause. In my reasoning, I keep coming back to paragraph 9, below.
8. KEY SYMPTOM, I think: Water got into engine oil and oil got out of engine into the bilge.
9. SUSPECT? Remote oil drain fitting/hose? Could this be a possible (or likely) source of the “two-way’ leakage. It appears to be original equipment, therefore like around 20 years old.
10. QUESTION: Does the engine have to be pulled to remove and replace this remote oil drain fitting/hose? If the hose were cut off of the fitting, could the fitting then be removed and replaced with conventional pan drain plug without engine removal?
This weekend, before taking it to the mechanic, I want to drain the engine oil; put in fresh; run with clean paper towels under the engine and remote oil drain hose and look for any oil leak in the area of the oil pan or remote oil drain. At the same time we would observe the engine oil to see if it was getting contaminated by engine cooling water. If the bilge is dry and water still gets into oil, we would know that the source is cooling water; indicating (in my opinion) cracked block or a possible gasket problem. If oil gets onto the clean paper underneath the engine, we would be confirming oil leak at pan/remote drain area.
QUESTION: If remote oil drain is the problem, then I believe that engine is still serviceable with new lifters (and pushrods); IS THIS LIKELY SO?.
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