COBALT223
New member
Hello,
I have a 1990 Cobalt 223 with a 7.4L Mercruiser. I recently purchased a new long block for the boat since I didn't winterize it in southern AZ and the block cracked. I salvaged the oil pan and intake manifold everything else like water cooled manifolds, oil cooler etc are brand new. I installed the intake, oil pan and other outside components and everything else back into the boat. The engine started right up using the water ears so I took it to the lake ran it for 30 to 40 min. checked the oil and oil had a milky look to it. The boat ran great no spit or sputter. Took the boat back home removed the intake manifold drained all oil/ water from engine, replaced filters reinstalled the intake manifold and head back to the lake. This time boat ran great for about an hour then the #8 cylinder rocker started ticking heading back to the dock I heard another noise like a knocking. Took the boat home removed the engine and the #8 cylinder has spun a bearing and there was once again water in the oil.. My question is the intake manifold I had for my previous 454 not correct for the 454 long block I bought? I'm not getting water in from the exhaust ports I have new baffles that would stop that and there is no signs of water coming in from the exhaust or pistons. The intake and head ports look smaller or is this correct. I tried doing a search and it seems as if there were several different options through out the decades?
I have a 1990 Cobalt 223 with a 7.4L Mercruiser. I recently purchased a new long block for the boat since I didn't winterize it in southern AZ and the block cracked. I salvaged the oil pan and intake manifold everything else like water cooled manifolds, oil cooler etc are brand new. I installed the intake, oil pan and other outside components and everything else back into the boat. The engine started right up using the water ears so I took it to the lake ran it for 30 to 40 min. checked the oil and oil had a milky look to it. The boat ran great no spit or sputter. Took the boat back home removed the intake manifold drained all oil/ water from engine, replaced filters reinstalled the intake manifold and head back to the lake. This time boat ran great for about an hour then the #8 cylinder rocker started ticking heading back to the dock I heard another noise like a knocking. Took the boat home removed the engine and the #8 cylinder has spun a bearing and there was once again water in the oil.. My question is the intake manifold I had for my previous 454 not correct for the 454 long block I bought? I'm not getting water in from the exhaust ports I have new baffles that would stop that and there is no signs of water coming in from the exhaust or pistons. The intake and head ports look smaller or is this correct. I tried doing a search and it seems as if there were several different options through out the decades?
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