What is the ZZ6 engine made of?

[Xxcaptinxx]

We are taking delivery of a 2024 Super Ski Nautique S21 with a ZZ6 engine next week. I’m not having much luck discovering what components make up the power plant. The Nautique engine is made by PCM engines starting from a GM short block. I found that the Chevy ZZ6 crate engine shares a name only, because it is 5.3l displacement while the PCM ZZ6 engine is 6.2l. The PCM engine is direct injection, so it can’t start from the carbureted Chevy LS series crate engines. That points to the Chevy LT series, which was once the LT1 line and is now the LT2 line. So will my 2024 Nautica ZZ6 have LT2 upgrades such as larger air intake and wide range air flow sensor, bigger cam, variable displacement oil pump and 2 new scavenger oil pumps, a smaller flywheel and better emissions control? Will it have the capability to shut off 4 cylinders for better low speed fuel economy? Or is it based on the older LT1 short block components?

Does anyone know which accessories and components in the 2024 ZZ6 engine are made by PCM Engines and not by GM?

Thanks for your help!

[NautiqueJeff]

I'll let someone else chime in on the engine information, but your S21 is a Super Air Nautique. There's no such thing as a Super Ski Nautique.

[Xxcaptinxx]

Well, I can’t demonstrate that I’m a Newbee better than that. Thanks for catching my goof.

[jpwhit]

In the past, marinizers like PCM would use truck short and long blocks. I'm fairly certain PCM doesn't buy a built up long or short block these days. They buy components such as the block, pistons, crank, cam, heads, etc. and assemble the engine themselves. They may also select some components from other engine lines if those components suit their needs. I believe the ZZ6 is mostly based on the Gen 5 LT1 components. Not to be confused with the LT1 RPO Code was used in the Corvette C4 between 1991 and 1996. That engine displaced 5.7 liters and was the second-generation GM Small Block design, and is therefore not related to this fifth-gen LT1.

The PCM engines don't match an exact car or truck engine anymore. Because the demands and desired power curves for a boat are different from a car or truck. Marine engines also don't use GM engine control electronics anymore either. They all use marine specific engine control systems designed by eControls. I've never seen a marinizer use any of the fuel economy features such as cylinder de-activation in their engines. Those technologies would be pointless in a marine application because marine engines never run at a lower enough power level where they would provide benefit. And they would create reliability problems at the higher RPM levels that marine engines run for extended periods of time.

Lastly, most of the marinizers won't tell you the exact components they picked for their engines. They seem to consider it a trade secret.

[Xxcaptinxx]

Thanks for that description, it makes a lot of sense. I have some more questions: I’ll have it serviced by the dealer through the warranty period, but after that will there be a parts manual or a shop manual available for the ZZ6? Is the PCM ZZ6 in the Centurion boats a different version from the one Nautique uses? Does anyone mod or tune these engines for more power, like high torque tractor engines? Is there any way to track fuel efficiency when using this boat? Does the ZZ6, with its GDI fuel system, have the problem with carbon buildup on the outside of the intake valves like some car engines experience? Is there a strainer cup in the PVC line intercept waste oil like some cars use?

Thanks for educating me about this unique engine!

[SilentSeven]

^^^ I think is pretty accurate. Sometimes you can sus out what the actual GM/Ford/etc part is by looking closely for stickers or stampings with numbers and then having someone like NAPA or similar cross reference those IDs. I've did this multiple times with good success on my GT-40. Distributor, sensors, etc. Was able to purchase an OE part or a replacement part at much lower cost than buying the PCM part.

[jpwhit]

I'm not aware of PCM making a shop manual available. I have seen parts manuals for some engines, but not for the ZZ6. I'm sure at least the parts manual exists, but most of the marinizers only provide that kind of documentation to the dealers. Ilmor, the marinizer MasterCraft uses, has a factory service manual for the engines they sell. It has plenty of useful info but isn't nearly as detailed as your typical automobile shop manual.

I think the ZZ6 used by Centurion is essentially the same. Maybe some small tweaks around things like mounting.

I've never seen anyone provide tuning for these engines. As I mentioned before, all the engine electronics are unique to marine and made by eControls. eControls is an industrial supplier and tends to be a lot more proprietary than automobile suppliers. But there is also such a small market for marine, that it's just not worth the time and effort for the tuning world to spend the effort trying to crack these eControls systems.

Yes, you can get fuel burn info from the eControls ECM. But the only real off the shelf "reader" that gives access to all the ECM data is Rhinda Diacom. eControls ECMs are based on the same protocols (J1939) and technology as other industrial equipment like heavy trucks and farm equipment. So some J1939 code readers for heavy trucks can be adapted to work with the eControls marine ECMs, but I've never personally messed with those because I have Diacom and it's just not worth my time to mess with other readers.

Yes, these direct injection engines have the possibility of carbon build up on the intake valves like any DI engine. But I haven't heard of it being a big problem so far with these marine engines. But they also haven't been around that long either. So, they may need walnut blasting of the valves at some point in the future.

I'm not aware of an oil trap in the PVC system.

As SilentSeven points out. A lot of the parts used are standard automotive parts. And with some investigation you can often buy the exact same part via the automotive supply chain for much cheaper then via the boat or engine marinizers. But, it's really important to know the marine engines well enough to know when the parts are really the same. There are some parts, especially electrical parts that are spark protected, that are absolutely not the same. And can be really dangerous to substitute the automotive version. Marine engines are in enclosed environments that will have fuel vapor at times, so the fire / explosion risks are real. Alternators and starters are prime examples of parts that are absolutely not the same.

[Xxcaptinxx]

Thank you for all that information. I think I'm going to either rent a Diacom from Ebay or try to locate one used. I can't say I have a burning "need" to know my fuel efficiency, since I have an hour meter and a tank gauge. However, this boat has a 65 gallon fuel tank, and I am trying to figure out how often I'm going to have to lug gas cans to the dock. We have no marina on our lake. Relatives are descending for the summer, and if we can burn through a full tank in a day of water sports, somebody is going to spend a couple hours every night retrieving more gas and filling the boat. Agiain, thanks for answering all my newbie questions, I'm sure there will be more.

[Scooter G]

Sounds like you've found your Summer workout routine. That's a lot of hucking gas down the dock, and that's going to get old real fast.
Is a rolling gas caddy an option (check Amazon)? I would definitely try to come up with some sort of pump option...
Are you in a location that you can set a tank and have fuel delivered? I have a 250 gallon diesel tank out back, usually save a little bit over pump prices, even having it delivered.

[gary s]

Probably not many left here that have the older Ford powered boats, but Ford had produced parts manuals for what they supplied to PCM- it included all their oem part numbers. Here is just an example of 2 pages I happen to have on me. I do have the complete book if someone needs it just don't have it with me