the deep

iTrader: (8)

You forgot to add whilst dragging a barn behind it ! Lots o drag to overcome verses wheels and transmissions .
I just had to add that i have seen car guys do this to boats and they didn't last 50 hrs .

Fenderjack

iTrader: (2)

I think the average boater does not hold his boat wide open like in poker runs ect.So the newer LS engines should prove to work well,if not better than the old big block type motors.Turbo's are the new wave,Make tons of power and are not as hard on the internals like the old roots and whipples.Avarage guy can't afford a rebuilds after 50 hours.And I think with the newer base motors and turbos are going to make a more user friendly big power market.Off course it will be helpful if performance exhaust systems would't cost more than people can afford.Just my 2cents JOHN SR

ToMorrow44

Building marine motors to sustain the current workforce at your shop would be tough unless you came out with something innovative like Ilmor did to compete with Mercury. If you started building LSX motors that are EFI and NA in the 500-700hp range that might be a good niche. Maybe if you did some marketing like putting "corvette" or "LS7" on the motor like Ilmor does with "Viper."

I agree that building marine motors that live is an art. As an engineer, I understand the brutal stress that a boat motor goes through, even at crusing speed. The motor is loaded hard 100% of the time. Marine motors aren't necessarily overpriced when you look at the cost of individual components like billet cranks, stronger blocks, billet connecting rods, AFR heads, efi supercharger systems, and jacketed headers which make the motors survive these stresses.

Yes you could build a 1000hp motor using a GM block, cast crank, cheap heads, etc...but its not going to last long pushing around a 38 Cigarette....

Rik

This might have more to do with the clearances than anything else as the marine engine operate at a lower water temp than a car engine does. Fresh water cooling might help those engines when used in marine applications.

TahoeRick

No way! Lots of boaters run at 190! Reason is the parts are not engineered to handle the loads of marine use

Rik

I don't know what configuration does. The engines I run, raw water cooled, never get the temp gauge to move off 140 degrees. Fresh water cooled Merc and other fresh water cooled engines do run hotter as to the point I was making.

I spoke with the GM guys today at the Miami Boat Show and they stated the new LS small blocks are all fresh water cooled and thermostated and they are stock car engines with rpm restrictions.

professor_speed

Alot of the Marine vs car engine stuff is just comical. Will a marine engine be built a little better than car engine? Maybe but maybe not.

Look at the parts that they are built with most are off shelf parts. Besides some of the uber builds its the same stuff guys are building race car engines with, nothing special, most of the stuff is not marine specific.

A good roundy round builder can build a solid boat engine.

Do you think that car guys can't build an engine with the same crank,rods pistons heads, etc? is a marine engine builder more talented than a guy that builds for Nascar? maybe but maybe not.

Look at most marine engines, Yes they are under load but they spin them Sloooow, most spin them what? 5000 rpm? 6500 maybe rpm for the HI-perf stuff, in the car world that engine would be turning 7500+ wear becomes exponential with engine speed. So slow the engine down and it becomes more reliable, magic

LS1's Were tested into the thousands of of hours at WOT, under load, before release. The standard most basic GM test is 300 hours of back and forth from peak hp to peak torque under load.

Of course there are considerations that must be accounted for when building a marine engine (cam valvetrain stability, oiling, operating temp etc) but they are not some magical unicorn engine. If they were every auto racing team would just have a marine builder build their Engines.

Marine guys (with the help of Mercury) are starting to figure out what Auto racers did a few years ago, Turbo's are the future.

I would say a good nitch would be Turbo LS engines. Turbos love a Load, The LS combustion chamber is great with boost, The bottom end is stout. Use manifolds, that cuts the cost of headers, not as pretty but cheap and reliable, offer it for decent price.

Build a 400ish cube turbo ls with a small marine friendly cam, smallish turbos it will make torque like blown bbc, forged rotating assembly etc, stock ls3 heads, you would have a hard time keeping it under 800hp.

TahoeRick

Very well put professor. Let me play devils advocate for a bit... First, weren't we talking about stock engines? Not NASCAR engines?
Didn't the ilmores have problems with broken cranks in the beginning? Not sure if that is true, but if it is, one could assume that a stock engine engineered for a super car could not handle the stresses of marine use. Also, if a stock crate engine would do just fine, I could pay $14,000 for a GM BB crate engine with 630 HP and have HP over a merc 525 that cost significantly more.

On a different note, as to LS engines, I am a huge fan of the LS7. Owned the 11th production Z06 C6. Put 60K hard miles on it. 6 bolt mains too!

professor_speed

I didn't hear that but maybe? I heard they had oiling problems which may have been the root cause of the crank failure. If you Own a vette and road race it you are probably aware that they will wipe the bearings if you do not do something to keep oil in the pan.(although you have an LS7) Thats is why the ls1 block was revised to the ls6, when that was not enough ls7's went dry sump, the damn thing would corner hard enough keep oil away from the pick up. and the pans are way shallow

There are some land mines with the ls stuff that one would not expect, LS7's although the most expensive are not the most robust in many regards, older cathedral ports heads are probably better suited for Marine applications, The flow is not as lopsided as ls3 heads, which already have to deal with wet exhausts , The LSX block is Good but IMO there are better options for the money, #7 cylinder runs hotter than the rest, depending on a number of facotrs the heads will lift like SBFs due to 4 smallish head bolts, etc.

I should have been a consultant for Ilmor I bet they ran into the same problems I ran into years ago, most of it is not major when get to the root of the cause but its not what you are expecting to coming from sbc/bbc stuff. (or um viper stuff) The LS is not perfect and will not replace a BBC in all instances but the gap is much smaller, and 600hp Blown BBC stuff makes no sense. (but I guess you have to save that XR some how )

If 600hp NA is the goal I pick the LS 9 times out of 10 to a bbc after that there are to many compromises and cost climbs real fast with ls stuff.

If you let me bring turbos into the mix, Its probably well past 1000hp before I want a BBC back. The combustion chamber of an ls, along with shallow valve angles and super stable valve train allow it get away with alot of boost, Hell I barley have any timing and still make power. You Just can't do that with older designs. ( I can't think of a instance where I would want an sbc over either)

On a side not Why does the merc 1350 run 7.8:1 compression? what is going on in that combustion chamber that 7.8:1 was deemed ideal? Maybe the LS has spoiled me

FIXX

iTrader: (2)

just saying what i have done in the past,,thease were just basic 350 cid chevy engines..i spoke with my uncle that worked at gm and he told me that mercruiser ordered then a specific way and they made them to their specifications..if you look at the late 80's and 90's when you bought a engine from gm they came with brass freeze plugs,,uncle said gm did that so if merc ordered a batch they could just put the proper cam and pistons in the engine..all the blocks were the same and the internals ..