First non GM block Merc.

[thumpar]

I don't know why they didn't just use the new generation of GM motors. Our Suburban has the 5.3l and it is a great motor. We are at almost 380,000 miles on it.

 

[oldjeep]

I don't know why they didn't just use the new generation of GM motors. Our Suburban has the 5.3l and it is a great motor. We are at almost 380,000 miles on it.

because the 5.3 is a gutless turd? But seriously they are still using the ls3 and lsa

 

[Mi duckdown]

you can Buy a GM crate motor For any boat .

 

[H20Rat]

Either cha-ching, or smart consumers will order their boats with more common engines.

Which means you have to go far enough away from any brand that has deals with Brunswick marine to even have that option... Really your only alternative is Volvo, which is 2x the cost now already.

 

[oldjeep]

I was referring to their other motors. 4.3, and ls based motors

 

[Scott Danforth]

A former employee of mine is one of the engineers on the project. the motor was released a while ago.

 

[gtochris]

I don't know why they didn't just use the new generation of GM motors. Our Suburban has the 5.3l and it is a great motor. We are at almost 380,000 miles on it.

I think the 5.3L had much lower torque than the 350 plus the aluminum block they changed to isn't favorable in a marine environment however as oldjeep pointed out, the 6.0L and 6.2L version of that block have found themselves into boats and are great since they have substantial more torque.

I'm actually very interested and hopeful for this 4.5L but want to wait and see a few years for reliability and durability. Boat test did a review (not sure if it is the link above) with this engine in a 23ft boat and it appears to perform very well- something you would not expect.

Has anyone else wondered- Why don't they post torque specs? Boats run on torque and HP really isn't a necessary determinant of performance when you have a large load to get moving/ plane out with. When Volvo came out with the 225V8 (last year?) it was advertised as 5.7L torque and 4.3L MPG which I can appreciate however what are we giving up with lack of displacement in the 4.5L?

 

[Watermann]

^^^ yeap here's the video of the water test. They don't get into the motor stuff until about 310 in the vid.

 

[slag]

because the 5.3 is a gutless turd? But seriously they are still using the ls3 and lsa

+1.0

 

[lg260ss]

I don't know why they didn't just use the new generation of GM motors. Our Suburban has the 5.3l and it is a great motor. We are at almost 380,000 miles on it.

Volvo Penta already has 350hp,380hp and 430hp versions of the (l96) 6.0l. I'm not sure where a 5.3 would fit into that (also GM has yet to marinize a 5.3l). If the 5.7 is being dropped however, It may be a good substitute for the 300hp range.

 

[Watermann]

because the 5.3 is a gutless turd? But seriously they are still using the ls3 and lsa

I have a 5.3 in a Tahoe, seems to me like a 325 CID small block with 320 HP / 335 Lbs of torque does fine hauling a big heavy SUV and would pull good in a boat.

 

[bobdec]

After a 40+ year run GM has not used the 305/350 (SBC) engine in any vehicles since 2003, looks like they decided the non-automotive volumes were not enough to keep a low tech dead horse going. As far as replacements, GM has been changing basic engine block specs around every 2-3 years since then as they chase weight, HP and MPG targets. To me that is putting the marine industry in a position of guessing how long any engine will be available. Maybe to the point where Mercury decided to take control of it's own power plant destiny. That way they know what going to be available 5 years out.

 

[QC]

Has anyone else wondered- Why don't they post torque specs? Boats run on torque and HP really isn't a necessary determinant of performance when you have a large load to get moving/ plane out with.

While I agree that higher peak torque will help plane a heavy boat, the reason it does is because it determines the horsepower at that RPM. Horsepower is ALWAYS what you care about. It takes torque, adds RPM, and voila you have horsepower. No way to calculate speed without it. Torque has no time in the equation, so time is irrelevant i.e. speed. Yes if you have RPM you can calculate something with torque, but then what you have is horsepower. Sounds like a circular argument, but it isn't. RPM adds time to torque so then you can cal speed.

Thus the reason they don't publish torque specs, what would you do with it? The only value in publishing torque specs would be to evaluate one power plant against another for planing. It would tell you nothing about top speed though. And, the only way the comparison would be valid would be if the RPM for peak torque would be the same for those two engines. If the WOT RPM was different it would also invalidate the torque spec because you would have to prop differently and change the RPM that was critical for planing. Or if gear ratio was different it would also invalidate the comparison. Ultimately it is torque and RPM at the propshaft that you care about. And if you have RPM then you are dealing with horsepower... If I have a 500 lb ft engine with a 2:1 gear ratio, I have 1000 lb ft at the propshaft. If I have a 1.5:1 ratio I only have 750. Which boat pulls harder? Which engine is stronger? Oh yeah, same engine

The one constant that will still allow you to calculate speed is horsepower. Then you build gear ratio and prop around that. Certainly not the torque spec.

 

[thumpar]

because the 5.3 is a gutless turd? But seriously they are still using the ls3 and lsa

Our burb is our tow vehicle. It is far from a gutless turd. Let me know when your dodge hits 380,000 miles.

 

[gtochris]

While I agree that higher peak torque will help plane a heavy boat, the reason it does is because it determines the horsepower at that RPM. Horsepower is ALWAYS what you care about. It takes torque, adds RPM, and voila you have horsepower. No way to calculate speed without it. Torque has no time in the equation, so time is irrelevant i.e. speed. Yes if you have RPM you can calculate something with torque, but then what you have is horsepower. Sounds like a circular argument, but it isn't. RPM adds time to torque so then you can cal speed.

Thus the reason they don't publish torque specs, what would you do with it? The only value in publishing torque specs would be to evaluate one power plant against another for planing. It would tell you nothing about top speed though. And, the only way the comparison would be valid would be if the RPM for peak torque would be the same for those two engines. If the WOT RPM was different it would also invalidate the torque spec because you would have to prop differently and change the RPM that was critical for planing. Or if gear ratio was different it would also invalidate the comparison. Ultimately it is torque and RPM at the propshaft that you care about. And if you have RPM then you are dealing with horsepower... If I have a 500 lb ft engine with a 2:1 gear ratio, I have 1000 lb ft at the propshaft. If I have a 1.5:1 ratio I only have 750. Which boat pulls harder? Which engine is stronger? Oh yeah, same engine

The one constant that will still allow you to calculate speed is horsepower. Then you build gear ratio and prop around that. Certainly not the torque spec.

I guess it's built into me when looking at cars and trucks (200hp 4cyl has a different characteristic than a 200hp V8- Granted no one makes a 200hp V8 anymore) While the Cruiser 23ft looks great in that video, I wonder how much the performance suffers when hauling 10 passengers as opposed to the Mercruiser 5.0L MPI?

I'm very much hoping for success of this engine. I think it will be a terriffic powerplant in a Stingray boat or another 19-21ft bowrider where it can offer V8 like performance with V6 weight, size and fuel consumption.

 

[theBrownskull]

I do like that the starter is located on top of the engine. Much easier than sitting on your head when changing one.

 

[achris]

Yeah, this isn't actually the "first" non GM block Mercruiser has used.

They used Ford blocks quite often back in the 70s-80s.

Also, they made their own 4 cylinder back in the 70s-80s also.

So much for inexpensive universal parts. A completely custom new engine will inevitably have more expensive parts than engines used in millions of boats, cars and trucks over the years.

But that is the cost of progress. On paper the specs of this engine actually look very promising.

And before that they used Renault engines....

 

[Slip Away]

Volvo Penta already has 350hp,380hp and 430hp versions of the (l96) 6.0l. I'm not sure where a 5.3 would fit into that (also GM has yet to marinize a 5.3l). If the 5.7 is being dropped however, It may be a good substitute for the 300hp range.

GM does not marinize the engines. They just make the blocks and supply them

 

[doyall]

While I agree that higher peak torque will help plane a heavy boat, the reason it does is because it determines the horsepower at that RPM. Horsepower is ALWAYS what you care about. ....

Apparently you do not do watersports.

 

[lg260ss]

GM does not marinize the engines. They just make the blocks and supply them

Then what is this? I know they aren't complete packages but they are much more than just blocks. Or am I missing something?
http://www.gmpowertrain.com/MarineEnginesControllers/ProductPortfolio.aspx