bmckay

I have a 1997 MerCruiser 5.7 in my boat. Well, it was in my boat. I had a rusty oil pan that needed to be replaced. The motor ran fine. But the mechanic convinced me that while the motor was out I should let him replace the internals, the old pump and water pump, etc. I agreed and paid for a complete rebuild kit to be installed. I had him rebuild the heads too.

When I got the boat back it was smoking, burning oil and bad blow by, low compression, and a growning noise. I took it back to him and while my boat was sitting next to his garage his entire garage and home burned to the ground. The gel coat on my boat is blistered from the heat, fixable though. All of his tools are gone and his home. He called me immediately and I drove out while the firetrucks were still putting out the fire. Needless to say my boat never got fixed and he’s basically washed his hands of helping me with it.

He told me the rings hadn’t seated yet, to just run it some more. So I took it out and within an hour the motor blew. Lost all compression on launch.

so I paid someone else to pull the motor out and it’s sitting in my garage. I’ve completely disassembled it. I’m going Take the block to a machine shop this week and I have a few questions about what went wrong. I suspect he used the wrong pistons and rings.

one piston had the ring land smashed tight to the second ring, the skirt was gouged on the side where ring was pinched, and there was a bad Gouge in the cylinder wall. This explains all the growning noise and I suspect the mechanic damaged the piston during assembly.

As best I can measure, the bore is 4.002”. Very little if any wear, no lip at all. The ring gap is .0027” and the pistons are 3.95” at the skirt/pin. That’s roughly 50 thousands clearance, way too much. And the ring gap is way too wide if I’m not mistaken.

Did he use the wrong pistons, or are the cylinders too worn for standard size pistons? If I’m reading correctly the bore is correct and, for marine applications, there should only be about .005” piston to wall clearance, and around .0015-.0020” ring gap.

Second question, I’m considering buying vortex heads for it. It’s a roller cam 350, 1997 5.7 LX tbi. If I buy vortex heads will they mate up to the stock Chevy/Mercruiser intake, or do you have to upgrade the intake too? And is it even worth it considering it’s TBI?

oilcanhenry

Take this dude to small-claims court.