Why no Hemi boat engines?

[jkust]

I am shopping for a more appropriate tow vehicle than my mini van. I am not a huge Chrysler fan but my search has lead me to see that the gasoline SUV's with Hemi engines have the most HP and Torque for their displacement and they are really cheap plus they have MDS to shut four cylinders down when not needed. I was just thinking then why do you all think there are no Hemi boat engines?

-Jason

 

[sportsmanphil]

Re: Why no Hemi boat engines?

I'd better stay out of this one

 

[180shabah]

Re: Why no Hemi boat engines?

Economics - ford and chrysler both used to have marine engines but slowly thier market share whithered away till there was none. It just would not make sense to marinize thier current engines for what would certainly be any even smaller market then they had previously.

Besides, if there were a marine hemi, I would expect about the same hp as a current vortec 5.7. Cam would have to be dialed down a little, restrictive marine exhaust, etc.

 

[mphy98]

Re: Why no Hemi boat engines?

i agree with what has been said before, plus, electronics play a big part in trying to convert the hemi over. true on the passenger and truck hemi the system shuts down 4 cylinders, but on a boat even at cruising spped i would think the drag would prevent this from working properly

 

[s1120]

Re: Why no Hemi boat engines?

Well the new hemi has a pretty complex engine mangment system, so would be costly to add to a boat. The old Hemi's were costly AND the heads were made more for good flow at higher RPM's. Not realy where you want it for a boat. I do belive that they were used once in a wile on boats though

 

[Howard Sterndrive]

Re: Why no Hemi boat engines?

"Hemi" is simply a trademarked marketing word for Chrysler.

It originally referred to a Chrysler engine that had a hemispherical combustion chamber that Chrysler neither invented, nor developed.

They were smart to trademark rather than patent.

A few engines with hemispherical shaped combustion chambers have actually been in boats since the early 1900's.

Most cars today have a combustion chamber design way more advanced than the simple round shape of a hemisphere.

 

[magillacuddy]

Re: Why no Hemi boat engines?

Nice username! I'm listening to Howard as I type this.

 

[abj87]

Re: Why no Hemi boat engines?

Ever check out the gas mileage on one of those suv's its a gas guzzler!

Now i want to see the gm LS series motors in a marine app.

 

[QC]

Re: Why no Hemi boat engines?

MDS would technically work well for RPM below 1200ish in a boat. Very light loads there allowing the four cylinders to be shut down. Not typically much time spent there though except idling around the marina . . .

You can get a Marinised Viper engine from Ilmor:

It is not Ford or Chrysler that holds this back or really even decides anything. I could go to them and say I want to buy engines and they'd say "how many". It is the Marinisers like Crusader and Merc and Volvo that have decided on GM engines.

 

[reelfishin]

Re: Why no Hemi boat engines?

.....................

It is not Ford or Chrysler that holds this back or really even decides anything. I could go to them and say I want to buy engines and they'd say "how many". It is the Marinisers like Crusader and Merc and Volvo that have decided on GM engines.

I'm sure if that's completely the case, I'm sure a lot has to do with sales volume and what is worth producing or not. A marine engine is set up quite different than a road run engine, since a marine engine is under constant load, and runs at higher RPMs the camshaft grind, fuel supply, as well as the exhaust and cooling systems have to be very different. In many cases not much is shared between a car engine and a boat engine.

The big three are more in the business these days to build cars, no so much just to supply engines. While GM and Ford do still supply some industrial and marine engines, I wouldn't think the volume is high enough to truly justify much new R&D.
I also would suspect that if GM fails as many have been predicting, then we'll see other engines being used in marine applications or possibly the current GM engines will begin to be built by another source, most likely at a higher cost.

Also if you notice, the GM based marine engines are no longer the same motors used in cars and trucks, the 4.3L and 5.0, and 5.7L have all vanished from the road in new models in favor of newer, more efficient motors. Those newer motors haven't yet made their way to the marine industry for some reason from what I've seen.

 

[NSBCraig]

Re: Why no Hemi boat engines?

Nothing matches up so it seems to be a big hassle.

 

[NSBCraig]

Re: Why no Hemi boat engines?

Took me a minute to find but here's the velocity VR-1 Hemi boat.

 

[windsors03cobra]

Re: Why no Hemi boat engines?

Nothing matches up so it seems to be a big hassle.

That twin supercharged big inch good style hemi.

 

[Silvertip]

Re: Why no Hemi boat engines?

You probably don't see Hemi's in boats for the same reason you don't see twin cam/four valve/cylinder heads. Boats need grunt down low to about 5000 RPM. Cost vs benefit simply isn't there. If engines were required to run in the 6000 RPM and up range, yes, four valve/dual cam/variable valve timing heads would likely be standard like they are on four-stroke outboards.

 

[NSBCraig]

Re: Why no Hemi boat engines?

I think it's really got to do with mating it to a Bravo drive.

I've read a couple threads on other forums and that seems to be the issue.

I think Velocity used a Konrad drive.

 

[AZSenza]

Re: Why no Hemi boat engines?

it would be cool BUT as much as I dislike Chevys I'll stick with a 5.7 Mercruiser any day... Its tried and true.

 

[Silvertip]

Re: Why no Hemi boat engines?

The 4.3 GM V6 has not disappeared. It's primary use over the years was in the Astro Van (circa 1985) and as the base engine in most of the full size vans and light duty pickups and cutaway vans to date. Every S10 Blazer/Jimmy and the vast majority of the S10 pickups were fitted with that engine. It is still the base engine in the Chevy/GMC work truck. The difference between a GM marine engine and it's counterpart in the auto/truck world is not as great as it's made out to be. Cams, core plugs and the accessory items that bolt onto the engine are different but the engine block, heads and internals are very much the same as the truck engine.