boatnt

What year is the boat? I would be surprised if you had a forged crank

jeff32

i burnt a piston like 15 years ago in a 496 mag.
I really could not tell why... some say you can run them up to 2000 hours no problem, some say they are proned to burn pistons...

so we changed the only one damaged piston, and never melted another one...
scary in my thoughts, but it worked... must have gotten lean somehow for a couple seconds...

Brad Christy

BoatNT,

Boat is a 2002. Engine was built in 2001, in that grey area when the HO may or may not have been built with the forged crank. I ran the serial numbers through Merc tech. According to their build sheet, it has the forged crank.

Thanks. Brad.

Brad Christy

Jeff32,

I spoke with Larry at Raylar and he suggested 90-95% chance we cracked a piston. If we recall, back in late 2022, I had an injector issue that resulted in the #4 cylinder running at about 40% fuel. If I had to bet, I'd say it's that cylinder with the cracked piston. I'd much rather it be something simple like a blown head gasket, but the likelihood of that is dwindling with every conversation I have with the various gurus there are out there.

Thanks. Brad.

Brad Christy

Guys,

I'm assuming potential worst-case scenario: We need to replace rods and pistons at the very least. I'm kinda over the "what-ifs" at this point, until we get a look inside the engine. So, I'm juggling options....

I've spoken to Larry at Raylar. Cool guy, BTW.... $1820 for a complete rod/piston set, including pins, clips and rings. Rods are SCAT I-beam rods to Raylar specs, whatever that means. I'm assuming they will be Merc OEM 6.693" rod length. Pistons are forged 4032 aluminum; no skirt coating, no specs on rings. These are on the shelf at Raylar, which has a fair bit of value in and of itself.

I am also looking at Wiseco pistons, which will also include pins, clips and rings, and Molnar PWR ADR H-beam rods. Pistons will be skirt coated, but still no specs on rings. Rod length will be 6.700" (I can't imagine the engine will even notice the .007" difference that can be made up for with head gaskets). I really like what I read about Molnar rods. From a toolmaker's perspective, the finishing process and the custom spec'd cap bolts are worth the extra money, IMHO. Total package is $1540 The pistons are cheaper, the rods are more, but the total is less.

So far, all the calls I've placed have verified stock on the shelf, either with the OEM or through retailers; Raylar, Wiseco (Summit), Molnar, SCAT (Summit) are all ready to ship.

We are also going to address the valve train with stronger springs and potentially Raylar's BP111S cam, as per advice from 87Mirage.

What does OSO have to say on any of this? Any suggestions on other MFRs out there? I'm all ears.

Thanks. Brad.

SecondWind

Brad,
If you’re replacing rods and pistons might as well address that cast crank.

Brad Christy

SecondWind,

Engine was built with a forged crank. If we get into it, and it does have cast, we will definitely address it while it's apart.

Thanks. Brad.

Tartilla

Hey Brad, what is your current peak HP and rpm?

What is your new power goal?

SecondWind

These would also

go well with the stroker kit. It sure is fun spending someone else’s money😃

Brad Christy

Tartilla,

ProCharger advertised their 496HO/M1 package at 615HP. I have no idea what we actually had. As far as I know, it was a factory PQ build; it's never been out of the boat since, let alone dyno'd. I do know we are turning 2" more pitch and running 10-15MPH faster than the same boat/engine combo, NA. I sent the ECM to Whipple for their stage 2 flash and asked them to set the rev limiter to 5350.

Goals: This is not an "upbuild", per se. I'm all good with improving performance while we're at it, but we are really just repairing the damage done and correcting some limiting factors and weak links in the process. With the forged pistons, we will be able to take it to Eddie Young for a live ECM tune (We have already discussed; he was unwilling to touch it with the cast pistons), which will likely render some HP, and we can elevate the rev limiter. If we end up replacing the cam with Raylar's BP111S cam, that will also render some HP. My guess is better valve train components and rods will safely allow for more RPM. At the end of the day, we still have the stock Bravo1 outdrive, so I have to keep THAT in mind, although we were already considering the XZ conversion, so we may address that while the drive is off. Scope creep....

At the moment, I'm really just seeking advice on MFRs of the various parts I've mentioned, past experience, etc. I'm keeping my hopes and intentions on a short leash until we have a look in the cylinders.

Thanks. Brad.