Picture of what is left of cylinder #1

I know of one thats forsale, but it's got 340hrs on it...Been absolutely bulletproof...Earlier 496's had forged internals in them...this is a 2002 motor so it might have them?

Some early 496's had a forged crank but I dont think any had forged pistons. From my tribulations with my motors I am finding that very few even had the forged crank. The nodular crank is actually pretty good up to 700 HP.

The cast pistons however.... suck! They are the root of almost all problems with the 496's

I suppose a couple bucks was saved to install junk pistons! What a shame...I was thinking of upgrading the power but I would need better drives than the b1x's...I dont think I want to spend that kind of jack now!

Sorry to hear about your 496 failure on a 40 hr. 496.
Let's not "Throw the Baby Out With the Bath Water"
When you consider about 50,000 - EFI 496's are out there in the marine world from all manuafacturers and maybe 100 or so have failed similarly and many of them from supercharging stock motors its not really a problem engine. This translates to a failure percentage of about .2% which is awesome by any standard.
Not to knock or bash blue engines by any means, if there were 50,000 blue engines out there I guaranty there would be at least the same number of failures from marine performance usage as I am guessing sure about 50-100 - HP525 engines have grenaded (1% - 2%) since their 2002 introduction and Mercury Racing has only distributed about 4,000 of these engines which would be a lot higher percentage of failure. When there are less of an engine out there you hear less about issues or problems.
Everyone is quick to blame the hyper-eutectic piston in the 496 (8.1L ) engine when in fact the piston in such large usage in large quantites of engines does very well with many 496's over the 700 -1000 hour mark and still going strong. When you consider how many kit 525HP Raylar 496's are running just fine with the same pistons you can see that the piston is not the biggest problem just one of the problems that appears in some cases where I suspect fuel delivery was the real cause of failure not structural piston failure.
I think everyone in the marine industry considers myself at Raylar to one of the industry's leading experts on the 8.1L 496 engine and as such I can tell you from all of our years of work with the 496 and developing parts and engine builds for this engine that that the 496 (8.1L) efi electronic engine is more durable and reliable than any marine engine that has ever been released in similar quantities.
It is obvious that when a hyper-eutectic piston fails it can have catistrophic effects on the engine at rpms and loads, your picture of that cylinder is a perfect example of that, however sometimes the failure of a forged piston can do similar damage at speed under load.
What all efi engine boaters need to pay more attention to and be careful of is the condition of their fuel pump, filter systems and related injectors on the newer efi engines.
With winter weather storage conditions and the higher concentration of ethanols in todays fuels, the buildup of WATER and MOISTURE in these efi fuel systems is at EPIDEMIC LEVELS! and when the fuel supply is leaned to the cylinder at speed under load the combustion temperatures climb so fast and are so destructive to the piston that these failures are getting more common.
Word to the wise here, carefully winterize your engines, service and replace all fuel system filters and discs, especially in the Merc CoolFuel III systems (those on the 2003-2009 Merc 496's.)
I don't think its an overkill thing to check your fuel sytem pressure at the fuel rail under full load in the boat running at speed at the first of the season and make sure the fuel delivery is not showing reduced pressures from fuel delivery issues. Some of the new fuel system cleaners and additives may not be a bad idea for those in the colder winter storage areas. You don't nearly hear of as many of this piston failure in the warmer regions of the country and world, yes a few, but my expierence seems to show that this failure do to fuel lean burn and resulting detonation and damage is about 5 or 6 times more common in these regions or where the boat owner did not properly service the fuel system yearly or do careful winterization methods.
In any event are forged pistons for the 496 engine stronger, you bet ,especially the ones Raylar has developed and sells for this engine. Can they or any other forged piston suffer damage and failure from fuel delivery problems, you bet, see and hear about it all the time!
Again, very sorry for your engine damage and loss and if Raylar can be of any help with a new redo for that engine or parts for your redo, let us know, we would do our best to make sure the replacements would be stronger than your stock 496 engine.

Hope my information and insight here can help possibly save more boaters from engine damage such as this.

Best Regards,
Ray @ Raylar

service and replace all fuel system filters and discs, especially in the Merc CoolFuel III systems (those on the 2003-2009 Merc 496's.)


Ray
what fuel filters does a 496 have besides the spin on fuel separator and what discs are you talking about?

Thanks

They are in the fuel pump box if its cool fuel.Not the side with the regulator the other.Loosen the screws in pull the handle the disc is at the bottom and the filter is in what cam out you have to twist the cover.

hi can you help my fuel cooler is on the right hand side of motors standing at front looking towards back can you tell me if i have these dics twin 496ho 2001 as i would like to renew if i have them allso wot would the correct fuel/p be at WOT 47 psi seems to ring a bell thanks paul from England ps great response makes perfect sense ray

While You're At It
 

It's a good idea to replace your spin on filter with the Raycor S-3213.

If you have the newer "box" where the lift pump, pressure pump, and both filters are all installed inside that one box, install the Raycor somewhere in line BEFORE the box.

This will help prevent you from struggling to get any water and debris out of that box. Really not a very good design in terms of maintenance.

If you've ever tried to clean one out ya know what I mean.

Having the clear bowl makes it nice to see what's coming out of your tank...