New Project -- 5.3 LS in my Bayliner Cabin Cruiser

[streetrover]

Hello all!

It's been awhile since I posted to the board. My previous project (MS2Extra on 4.0 Land Rover Motor in 1975 Porsche 914) is still working great and provides me with unending pleasure! So now I'm beginning a new MS project. I'm replacing the old 350 Chevy motor in my boat (1973 Bayliner Skagit Cabin Cruiser) with a rebuilt 5.3 LS motor from a 2007 Chevy Silverado. I have a couple of questions that need to be answered. First, my machinist noticed an oddity with my engine. Apparently the early engines (1999-2007) have a 24-toothed flywheel, which this one does, but mounted the knock sensor deep inside the block while the later models mounted the knock sensor in a more easily-accessible bung on the side of the block. The knock sensor bung on this block is on the outside. How odd is this really?

Further, since on a marine application it's going to be d*** near impossible to run O2 sensors because of the saltwater rushing through the exhaust risers to cool them (unless you know of a work-around) I'm anticipating running an open-loop configuration. In an open loop configuration does the EMS even bother with data from the knock sensor?

Additionally, I noticed that the MS EMS doesn't use the cam sensor in any configuration for the LS engine....true?

Given these parameters which crankshaft should I put in the engine -- the 24-tooth or the 58-tooth? Does it matter?

Lastly, which megasquirt model is going to be best for my application. At this point the MS2Extra seems like my best bet. Thoughts?

Thanks in advance for your time and thoughts!

Bob

[nathaninwa]

Seems like gm did some weird stuff with the gen4 5.3. My buddy just picked one up, 24x crank with gen3 799 heads. Motor was a 30k mile swap from a bad rod bearing

So your options are open. The side mounted knock sensors I like a little better from there location. Run which ever crank wheel you'd like, and not sure with the ms2 code, but we do use a cam signal with the Ms3 stuff. If you run the 24x crank, be sure sure to run a half moon LS2 timing gear, if your running a 58x you can run either the LS2 or the 4x cam gear

Not running an O2 might be tricky. You need to get the initial open loop table tuned using a wideband. But having closed loop fueling is really cool as well

Anyway to engine dyno tune this before going into the boat?

Edit. Was this a dod engine? And does it have the rear mounted cam sensor or a timing chain cover mounted sensor?

[Matt Cramer]

MS2 does not use the cam sensor as it doesn't have enough I/O to make good use of it. MS3 is capable of full sequential operation, so it can use the cam sensor.

[streetrover]

Thanks guys!

So far it sounds as though it doesn't matter which trigger wheel (24- or 58-toothed) I use on the crank...either will work...right? And MS3 is the better option then because I have the option of going with full sequential injection. But the full sequential injection uses the cam sensor. Is the "4x cam gear" is the newer of the two options and thus with a 58-toothed trigger wheel and 4x cam gear the engine would be more identical to the later model (2008-2017) engines?

I don't think it's a dod motor because I'm not sure what dod refers to...Department of Defense?

My earlier project (Land Rover V8 in a Porsche 914) uses an open loop system because I could never get the d*** Innovate wideband O2 sensor to work properly. Nevertheless it runs like a champ. I'm hoping the same would be true for this engine. It would seem more reliable too because there are fewer sensor to go bad and mess up the tune (once I've got it dialed in nicely).

Dyno-tuning the motor might be a great option before dropping it in. I'll need to think about how to make that happen!

[whittlebeast]

As far as ECU choice, I would be partial to a MS3 Pro. I have had boats and racecars for 30 years and the water/humidity is one of the devil in the details. Go waterproof. Worth every penny of the difference.

I am not an expert in all the options in the Chevy world but it really is easier to set up a system when you know cam position. O2 sensors hate water in the exhaust. You may want to consider going with an old Ford MAF. They are not real crazy about water so it would be best to keep that issue in mind if getting creative.

Andy

[nathaninwa]

The DOD is displacemnt on demand and generally have vvt as well. All of which are typically replaced for a traditional cam and lifter setup

Call around on dynos. Some may or may not be setup for efi so you might have to bring stuff like fuel pumps and things. And I would question the loading. You can dyno in a cell which may not have the same loading as your boat in the water, so the setup would be lean in the boat. Would be cool to get a wideband installed, even if it's tempaory

[whittlebeast]

Boats are on a dyno all day long. I have tuned EFI without widebands by moving the VEs up and down and simply seeing where the motor was happy based on RPM coming up and down. We did it for years with carbs and never questioned it.

In boats, great repeatable starting, rock solid reliability and reasonable fuel economy are the big things.

Andy

[streetrover]

Ok...got it! DOD = Displacement On Demand... which I'm pretty sure means the ability to disable/enable cylinders (effectively making the engine a V6 or V4). Yes, the engine had that but my machinist is making a custom cam that nullifies that component. He was vary curious though about the cam sensor, hence all my questions. MS2 doesn't need a cam sensor but the MS3Pro looks like the way to go...possibility of one day setting up sequential injection and also apparently more weather-resistant. ANY DISADVANTAGES of telling my machinist to install the 58-toothed crankshaft along with the later 4x cam sensor drive and then running the MS3?

[streetrover]

And yes, that's EXACTLY what I'm shooting for ... rock solid reliability, the ability to repeatedly turn off and start the motor depending on where the fish move, enough fuel economy to get me to Catalina Island and back on a tank (50 gal) of gasoline!

[nathaninwa]

Nothing wrong at all with 58x, I think it's a little better anyways for either setup and the 4x cam gear ran on poll level. I'm running a Pro with the same exact setup. Rock solid

We actually just had a thread where the owner was having huge issues with a 24x setup and actually found the wheels to have come apart from one another causing all sorts of issues