Makin a long story short...atleast attempt to:
Spent 6k+ (in april of this year) and had a 454 built after i grenaded the old one. Somehow after 5-7 river/elsinore trips I noticed my oil pressure dropping and i found myself adding 2 quarts on the spot. Put it on the trailer, had black exhaust/oil on the back of the boat and minor smoke out the oil fill cap at idle. Didnt notice any pinging or knocks, ripped the motor out and sent it back to where i had it built.
Stopped by his shop today, 2 pistons are toast and the other 6 have knicks and dings on the tops.
The crank, rods, cam, etc. are all ok according to him.
What he told me was my fuel lines (3/8") were too small and the fuel pump was big enough to keep up with motor. (kept it from the old motor which was a stock 454).
He also mentioned a possible vacuum leak near my carb.
I am far from a mechanic, but is it possible to cause all this damage by lack of fuel?
A number of questions come to mind. What was the static compression supposed to be? How much ignition timing (total timing) were you running? What fuel were you running?
I don't think the 3/8" fuel line would be the issue, I recently dynoed a 468 Chevy at 606 HP,, with a 3/8" line. I am using 1/2 fuel line on the 632 cu in engine that I have ready to go on the dyno now.
I think I can see marks indicating a piston was hitting the cylinder head, but would not make such a statement based only on these photos. The deck height, combined with gasket thickness would equal the "quench" that GT mentioned.
It's possible a number of factors combined to cause the problem. If the compression was marginally high, and you ran some bad or cheap gas,, or 87 octane instead of 91 octane,, combined with a vacuum leak, etc etc.
Years ago I build a 9.2-1 compression engine for a friend's Suburban. His kids drove it to the river admittedly at 120 mph at times,, towing a trailer. When the engine temp was showing to be too warm, they continued to run,, (backed it down to 100 or so). They not only burned a couple of pistons, but the block and head got torched, like a fuel dragster,, about 1/4" material gone. I knew it had been tuned on a reputable chassis dyno, but also suspect the boys bumped the timing up looking for more power.
Boats (particularly jet boats) get run hard, often for extended time periods at higher rpm than you normally run a street engine.
