1992 4.3 failure

[rl65028]

First trip of spring, ran fine in fall. Low power 3800 RPM WOT. starts knocking shut it down bilge full of oil. towed in. After further review #2 exhaust valve sucked inward dime size hole center #2 piston. All plugs blackish only 1 a nice tan. Exhaust man 3yrs old aluminum and looks fine. Anyone have a theory? How can this be prevented again?

 

[Docksidemarineservices]

Left over gasoline from last year will run your engine lean tulip a valve and burn a hole in your piston. You can thank the ethanol.

 

[johnson123]

YES, that's what happened to my motor. use Lucas ethanol treatment

 

[rl65028]

Thinking about buying a 4.3 longblock from US engine Inc. They advertise an extra 50 horses (through non standard pistons and cam) for 1850$. Anyone have any experiance with them?

 

[jkm3093]

No experience with US Engine but I am currently repowering my 1994 with a brand new GM Marine 4.3L Vortec Long Block that is supposed to put out 225 HP compared to my original 180 HP with 4 BBL carb. I have a thread on here about that. I bought it from MarineEngineDepot.com for just under $2,500 plus $180 for new intake manifold plus $135 shipping. I decided to spend the extra $500-700 for brand new rather than rebuilt for the piece of mind but the wisdom of that could be debated. I haven't decided what to do with the old long block but it probably has a value as a core of about $300 that offsets the cost difference. I expect to fire iit up sometime in May. Good luck whatever you do. Jim

 

[rl65028]

Thanks to everyone, good luck with your project also Jim.