87 omc 350 hole in1 piston

I had a Remanufactured**engine installed in 2007 , have less than 50 hrs on motor, have hole in piston, the new *engine has a roller lifters if it makes a differents.* I had several promlems with the Mechanic that installed and replaced engine 3*times with promblems and do not wish to take back to him. I am putting*1 new*piston and all new rings rings *in motor.* But my promblem is finding out what caused the motor to miss fire and damage only one piston, the boat seamed to run and idle *very good. did not here any ping or miss firing before hole in piston. I will rebuild carb, install new points, cap, plug wires, even through it alll looks good, could*I have the wrong cap are they prety much standered on the chevy 350, any ideas of how to track dwon the promblem so it wont happen again ****

Leaning out the idle mixture with out moving the idle screws together.
One side of the intake manifold will be way rich, and the other will be way lean.

Too much advance, spark not reaching the cylinder at the correct time.
If the spark is not getting to the cylinder at the correct time will blow a hole in a piston quick like.

Poorly made pistons, cheap chinese made maybe.

Bored way over sized.

Wrong cam maybe ?

Carbon on top of the piston.

Wrong spark plug, way too hot maybe ?

Shape of the head of the piston ?

Who built this motor ?

Without seeing this piston, it's tough to say what the cause was.

I highly doubt that any low speed fuel/air calibration would have any affect on this.
High Speed fuel metering....YES!

With our marine engines, and like Chief suggests, Ignition timing..... and in particular the progressive ignition advance, can and will cause Detonation.
Detonation may cause the piston damage that you describe.
Detonation and Pre-Ignition are not the same phenomenon. They are two entirely different issues.

Questions:
Did anyone check the progressive ignition advance before you set out to break-in this engine?
Or... did they set BASE advance ONLY, and turn the other cheek?

Which pistons are being used in this build?
If full dished, you have a battle right out of the gate, for any SBC Marine gasser.

Suggestion:
Run your ignition system on a Distributor Machine.
Watch and note the progressive advance.
Plot this out in graph form up to approximately 3.2k rpm.
Compare to your OEM specs for this particular engine build.
You may find your problem right there.
Examples:
Full In advance occurring too early as per rpm.
Too much TA (total advance) at the full in rpm.
Either may cause detonation.

What ever you do, check this out first, before you re-use this ignition system after the piston has been replaced.
You do not want a repeat!

Without seeing this piston, it's tough to say what the cause was.

I highly doubt that any low speed fuel/air calibration would have any affect on this.
High Speed fuel metering....YES!

With our marine engines, and like Chief suggests, Ignition timing..... and in particular the progressive ignition advance, can and will cause Detonation.
Detonation may cause the piston damage that you describe.
Detonation and Pre-Ignition are not the same phenomenon. They are two entirely different issues.

Questions:
Did anyone check the progressive ignition advance before you set out to break-in this engine?
Or... did they set BASE advance ONLY, and turn the other cheek?

Which pistons are being used in this build?
If full dished, you have a battle right out of the gate, for any SBC Marine gasser.

Suggestion:
Run your ignition system on a Distributor Machine.
Watch and note the progressive advance.
Plot this out in graph form up to approximately 3.2k rpm.
Compare to your OEM specs for this particular engine build.
You may find your problem right there.
Examples:
Full In advance occurring too early as per rpm.
Too much TA (total advance) at the full in rpm.

Either may cause detonation.

What ever you do, check this out first, before you re-use this ignition system after the piston has been replaced.
You do not want a repeat as a result of an incorrect ignition system!

Perhaps post which ignition this is.

On the issue of the one piston only, this is rather odd, but does occassionally occur.
In order for only one cylinder to receive too much Ignition TA, or Ignition Advance too early, the cylinder firing seperation at the distributor would need to be off. That too would seem unlikely.

.

Here is apitcher of the piston, I guess the ingnition is Prestolite, the old style with points,

I posted a reply at another board, but ouch.
If it were me.... (and I didn't already have a nice running L48 350 from a car sitting in my garage that I am familiar with), I'd go with a new 290HP/350 GM crate motor and a Delco Voyager ignition from Michigan Motorz, put brass core plugs in the block and do a real thorough check of carb and intake. Maybe a Performer intake and 1409 carb just to make it all new, but then I'm pretty good at spending other people's $