Hi all, first posting in this section. I'm gathering parts to assemble a replacement engine for my boat (mild cam'd Vortec headed SBC), and would like some experienced opinions to check my thinking, please and thanks.

I so far have a used 6.2L L92 long block, used but clean LSA supercharger, new ZL1 lid, ARP head stud kit, and finalizing part collecting to replicate the CTS-V accessory drive (FEAD). Plan is to run pump E85 exclusively, as it is a small boat (16.5'), easy to refuel on trailer, and short distance range OK. I'm considering to run a 224/232 115 cam due to this Richard Holdener video: (6:51 key point). I do want a noticeable idle.

Plan to run the stock LSA blower pulley, with a 10" Lingenfelter crank pulley on an ATI damper. Max engine speed would be 6,000rpm. The lid intercooler brick will always have 75F lake water or colder pumped to it. Is 10" crank pulley too aggressive? I upped it due to E85 and adding the 224/232 cam, which should lower blower pressure, guessing it to be about 14psi max or so?. Suggested compression ratio for an exclusive pump E85 fueled engine?

Stock non-forged 6.2L crank and stock Gen IV rods expected to live? Seems so, but let me know otherwise. I can spend more for forged rotating, but is the forged Chinese 4340 stuff better than the stock GM pieces? Will go forged pistons regardless just for the margin of safety when tuning, if nothing else. Injectors need to be about 1300'ccs? What brand valve springs is everybody liking, and go dual or beehive?

Thanks for your input, much appreciated. Targeting approximately equivalent of 100,000 miles and/or 15 years of longevity. 95% of time is just up and cruising, 5% is short full throttle blasts for 20 seconds or so. No prob to change valve springs as needed. Apology the request for opinions is kind of scattered and not just a single question, but would enjoy to hear from those that have built similar.

 

One btt, then I'm just going for it.

Looks like LSA doesn't get too much love in this dept vs turbo, rightfully so I presume. I just can't do a turbo in an enclosed fiberglass engine compartment.

Appreciate any insight.

 

LS in a 16.5' boat with an enclosed engine? Pics please and specs on type of drive etc. Cannot help with your question. Just interested in the boat. I am just taking a guess as to why no replies but as for me (I assume this is not a widely held opinion) I cannot stand to watch his videos.

 

Going for 700-800 something like that?

 

Not a big deal on the replies, I can learn as I go, just thought I'd ask. Yes, it is a 1984 16.5' Formula I/O, closed bow. Came stock with a MerCruiser 4 barrel 4.3L V6 and Alpha drive, did 51mph. I replaced the great running 4.3L with a mild 350 (5.7L) SBC Vortec build, got to 67mph, ran that for 15 years, it is now tired. Switching to 6.2L LS build with LSA blower, and likely pump E85 since I trailer it and E85 is available everywhere here. Seems blowers really like it, adds +40hp-50hp due to the evap cooling, but largest for me is a huge safety margin for tuning. Bought a used Bravo drive, so will be switching engine and drive at same time. Hoping for 70mph. Yes, target approx 750'ish hp. There is much more LS build experience here than on any boat forum. I run it about 10hrs per weekend all MI summer. 90% cruising RPM, 10% WOT.

I did also pick up an Ilmor 522hp LSX 454 engine, but not going to use it due to the weight of the cast iron block and cast iron exhaust manifolds. In that short of a boat, I'm really trying to keep the weight out. That motor does have a beautiful rotating assembly though. All non-Chinese forged, H beam, from the factory with warranty. Pretty slick.

Guy and kids are neighbors out with us that day.

 

I'm not a boat guy, but 14 psi on E85 assuming that the water cools it decently is fine. Also for compression personally I'd have no problem going up to 10.5:1 for a boost engine on E85.

Probably also plan on pinning the crank.

 

10-4, thanks for your input.

Agree on crank, I think the ATi damper I need to use to change the blower drive ratio has a keyway into the ID of it (?), and if so, I will have a corresponding keyway cut into the crank snout during balancing.

 

Not a pro and not a boat guy but I do know that a boat is unlike a car and will spend proportionally much more time at higher RPM, is your 90% cruising over like 3500 RPM still? Big cam with big springs in a car usually need removed and checked every 20k miles. In that video one of the cams was like .600 lift which is a big swing for springs. If it were me I'd be doing my best to keep it reliable as well as powerful so I don't get stranded out on the water in a boat. :-) Just thought I'd throw that out there to make sure you're considering that. Stockish lift is designed to go 100k+ in a car.

 

I'd add in a trunnion kit for the rockers.

Max of 6000 RPMs with an occasional 20 second run WOT sounds fine to me.

I'm running a Melling oil pump in my '67 camaro turbo build, I think its the one ending with '96 but I can check if you like. I'd be spending some time making sure the oil system is solid.

 

This forum is chock full of 1/4 mile racers. Look into road racing forums for good advice. Your boat will thank you.

 

Have you ever had a boat you regularly had to put ethanol fuel in? Because I have and its probably the one place I would avoid ethanol at all costs.

Ethanol absorbs water, right out of the humid air even, and that is one big pain in the *** when the vehicle in question operates exclusively in water. The injectors are going to need to be cleaned and/or replaced all the time, fuel pumps go bad, filters rot out...
The alcohol just absorbs the water from the air everywhere else in general. It was a grand nightmare to deal with that boat. You had to keep brand new injects on hand in a vacuum sealed bag for emergency replacement out on the water.

e85 and boats...not a great combo IMO.

 

Yikes. Was that boat docked or pulled out of the water at the end of the day? I have no experience just interested.

 

I would be more concerned about things like the “X” dimension when you switch from the Alpha to the Bravo.
Is it a Bravo 1? Not the strongest drive. When your getting into 500HP and above you should be considering a drive with a separate transmission.
It seems like there are easier ways to get an additional 3 mph. Nose cone, trim tabs, prop work.

 

Thanks for all the input, appreciate from all perspectives.

Yes, cruise RPM will be 2400-3000'ish RPM range. Engine will have a lake water cooled engine oil cooler as well. Trunnion kit already ordered, thanks. Understood and agree on reliability, cam lift is 0.595"/0.595", Cam Motion quiet "XA" lobe profile.

Have never had an E85 fueled boat. Your situation sounds extreme but real. Trying to think of why cars would not have that level of issue but you did? Must be due to a continuously open tank vent being docked in the water all summer long? My plan was to do something unique to combat this, was going to put a 1psi check valve for tank pressure vent, and then just a 12v actuated solenoid for the inlet vent that opened only with ignition power on. This will keep it sealed, able to vent out, desiccant can on the inlet vent for when it is open and in use. Plus this boat is a smaller trailer craft, not stored in the water. I enjoy new challenges and system designs. This needs more consideration as it may ultimately determine piston selection, ie do I build a dedicated E85 boosted engine (10.5:1 or so and 15psi), or do I lean safe, spec the compression for gasoline boost (9;0 or so and 10psi) and go that way.....?

Boat is so light that in reality, I'll never be able to fully load the engine down to absorb 700hp or so. It is just replacing a tired 350'ish hp Vortec SBC, and I always wanted to do a blower build. Price differential to design for 750hp vs 550hp stock LSA not that large (cam, compression, blower ratio, E85, injector size).

Yes Bravo 1 drive (used at that). Alpha and Bravo X dimensions are the same, it is a big mis-conception that the Bravo is longer. It should be fine, I won't slam into it hard from a dead dig, and I won't prop it steep enough to use all the engine hp anyway, boat would go way too fast beyond its design.

Apology again for a boat question in an automotive forum, but the there is just not even 10% of the knowledge on boat forums vs here. Thanks for the input.

 

Well you can make 10+ psi on pump 93 so there's that. You don't need to go down to 9:1 compression.

But E85 will handle 15 psi (intercooled/cooled) with ease, and your cam spec is nothing crazy.

I'm running a spec'd Melling xxx96 oil pump (I don't remember the parrt number). To keep stuff safe you'd want to program the ECU to pull timing if your inlet air temps get real high.

 

Yep. Thanks for the replies John and all, appreciate it. I also bought the Melling 10296 oil pump.

 

Where are you located, how to do plan to tune the combo?

 

Perfect question. I'm in Livonia, MI. I did buy and started to study HP Tuners. I do factory OBD-II calibrations for Mitsubishi Motors here in the US for their North American market vehicles, but only for emission and diagnostic requirements, nothing engine performance. Honestly, my very first calibration should probably not be on a fairly expensive engine build. There are several large name brand shops around here in MI, Livernois Performance, etc.... I hear of people being able to remotely do it as well. I'm all ears if you have anybody you'd recommend. Can run dry exhaust if using engine dyno. Otherwise, I was going to start with a base LSA calibration (tune), get it to start and idle stably in the boat, increase fueling by approx 30% everywhere, and go from there, starting at idle and working up with dual AFR gauges. A little risky, but that is part of why I chose E85 fuel as well, for its knock tolerance.

 

I've seen a few tuner friends who are on FB have some experience with boats as well, I'll ask one of them his thoughts. You could tune it yourself though having a pro look it over might be a good idea. Dan Millen @ Livernois might be one, though boat experience might be handy.

 

I think I would reconsider the E. I say that just because for what your looking to do, with a unlimited supply of cool water, I don't think it's worth the trouble. Between the fuel cost, and amount of fuel it will use, I think 91/93 would be a better option. I don't know about there, but here, I've never seen E available on the water. I realize you said you were going to fuel it on the trailer, but I also know how the best laid plans work in my world.
Other than that, I think it sounds like you have a solid plan. I'd possibly also consider a Term X on it, but that really depends on how comfortable tuning with HP Tuners you think you'll be.