Old Motor Dead New Motor Problems
 

Exhaust valve broke off and put a hole in the piston and cracked the block, brought the boat to Derebery Performance for a complete rebuild last September. Asked to build the best motor we can but re-use what we could. So kept the B&M mega blower, carbs, etc. Upgraded the fuel system because was told could have been to lean with the twin blue Holley pumps. Long story short here, breaking in the motor everything running good pulled back off the throttle to idle and motor sounded like it was missing. Shut her down, pulled the dip stick and it was full to the top; water in the oil. My heart dropped. TOW BOAT US to the rescue. Brought the boat to him the next day, today. Hit the kill switch. Pulled the dip stick and showed him, commented that’s not good. Listened to it turn over, commented on how the exhaust could pull the water into the motor. I was going to pull the boat to Havasu this Wednesday. Now I get to feel sick to my stomach. I guess the mechanic is out and they will break the motor down Tuesday. I got no answers today. WTF? Anybody know what could have happened?

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Any chance the timing is not set correctly? I had my blower engine blow both head gaskets, all 8 cylinders when I went into boost the first time after replacing a long block. The only two causes we could come up with were the fuel injection leaned out, or the timing was off because the ecu was not put into base timing mode when the timing was set. As far as the injection we never found a problem but the result was a block full of water & the boat was missing all the way back to the dock. (100yds or so fortunately) Hopefully that's what happened cause it's an easy fix, if not I hope the best for ya. Randy

Did they dyno the motor?

maybe it leaned out on that cyl, dropped the seat and bam, you didnt hear anything funny or loud banging

It could have been a head gasket because it might have been the first time it went into boost except they did dyno the motor.

When the exhaust valve went on the old motor I was giving it a punch after getting to pane and a big back fire then it sounded like ther was a hand full of gravel in the motor.
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This is the fuel pump they put in. I also requested a water filter for extra insurance.

Not sure the details for the pump and I figured I would change the filter every 50 hrs.

What's the cam specs? Those look like real short risers and water hitting the backside of a hot valve could cause it to fracture. Any pics of the other pistons?

only other pic I got.

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If the coolant water exits the block and enters the bottom of the exhaust manifold. How does the riser height come into play here?

Reversion, water actually gets sucked down the riser and into the manifold.

Got it. just found a cut away pic here on OSO of a manifold and riser. this one in particular had a lip in the riser.