Chevy LS1 engine in the boat

[Walt T]

Re: Chevy LS1 engine in the boat

The LS1 claims to get it's HP from a ram air effect which is meaningless in an enclosed engine compartment. This engine was made for the Corvette an is also used in aircraft. It is designed to produce its maximum power at the upper rpm range which isn't usually conducive to marine use. However in your little 18 footer its not like it needs a lot of low end grunt anyway.
No parts from the SBC are interchangeable, you will need the entire EFI system and the electronic controls. The ECM must be a marine program. For the massive expense and not that much gain, you're way better off with a stroker if you want high performance, or just a good solid 350, I'd go Vortec. The extra weight won't bother the boat.
The LS1 is 425 lbs, the SBC is 530 lbs, The 4.3 is 370-400 lbs.

I should mention I've seen some pretty awesome 4.3 modifications and 400 hp claimed from them. That was in automotive applications but I can imagine a good solid build for marine use. Might be worth looking into.

 

[Scott Danforth]

Re: Chevy LS1 engine in the boat

Marine/shmerine, i love blowing up boats.its efi how is an "automotive" as you guys like to say efi system going to blow up a boat? Now i could understand a carb bieng dangerous. In the end it comes down to you, run the blower make sure you have no fuel leaks. I know im gona cetch flak for this

xjdriver your an idiot. first off, automotive efi needs to run closed loop - that means O2 sensors, etc, Marine EFI runs open loop without the addtional sensors and the electrical is shielded. to top it off, the fuel system on the automotive side is plastic, marine is stainless. if you have a fuel leak because your plastic fuel system parts failed, and your non marine ignition and electronics sparks the explosion. suffice to say the blower will not help.

The LS1 is 425 lbs, the SBC is 530 lbs, The 4.3 is 370-400 lbs.

and the SBC with aluminum heads and intake is about 455 without carb. so put it in the #465 range. So the aluminum block on the LS1 will save you #40 over an SBC with aluminum heads. to that you have to add a bucket full of cash.

 

[HorizonblueDK]

Re: Chevy LS1 engine in the boat

Before we get too carried away by discussing EFI, I will mention that I lean more towards a carburetted setup. Should be easy to find a marine carb and an approved electric fuelpump.

 

[xjdriver]

Re: Chevy LS1 engine in the boat

I believe they actually make a conversion kit which allows you to run a dist and a mechanical fuel pump. Seen it on powerblock tv.

 

[Scott Danforth]

Re: Chevy LS1 engine in the boat

I believe they actually make a conversion kit which allows you to run a dist and a mechanical fuel pump. Seen it on powerblock tv.

Thats a front mount distributor driven off the water pump. it is NOT J1171 compliant

 

[xjdriver]

Re: Chevy LS1 engine in the boat

Thats a front mount distributor driven off the water pump. it is NOT J1171 compliant

Pace Performance - GMP88958679 - GM LS Engine Front Distributor Drive Cover Package
Im sure you could get it without the dist, and put a marine unit in, no?

 

[Walt T]

Re: Chevy LS1 engine in the boat

The LS1 is designed to be fuel injected and computer controlled. Sticking a carb on it assuming you can even find a manifold is counter productive. Not gonna happen in my opinion.

 

[Scott Danforth]

Re: Chevy LS1 engine in the boat

for the LSX engine to run as carbed:

Carb manifold in aluminum $450
Gaskets - $150
closed cooling system (full system) $1000
LS front distributor drive $450
Marine Cam $600 (estimated)
Marine Carb $400
now to find a compatible J1171 distributor, etc.
design and weld up custom exhaust manifolds
spend a bit of time

can it be done - yes
has it been done - yes (many jet boats running dry exhaust headers)
will someone do it to an I/O - probably
is it inexpensive - no
is it practical - no

When done, you have just exceeded the cost of a marine SBC, and are approaching the cost of a turn-key marine LS putting out 380hp or more with the proper marine EFI, etc.

 

[xjdriver]

Re: Chevy LS1 engine in the boat

I may be an idiot, but i think he would be better off building the 4.3, complete rebuild, bore 30 over, stroker crank, port and polish heads, new cam, bigger 4bbl carb, and its still what the boat was made for, just putting out a couple more ponies.

 

[mr 88]

Re: Chevy LS1 engine in the boat

You are now approaching a " fortune " with your quest for more speed. I would follow the advice of the above post,turn that 4.3 into a mean lean fighting machine. IMHO I do not think that 18' boat you are running could handle the HP and added weight of all the changes needed to be done. As the saying goes you can put lipstick on a pig...but you still have a pig in the end.Your boat to the best of my knowledge is not a performance designed hull and by sticking 375 hp on the transom you now have made a ticking time bomb.never catch me in a ride like you are talking about,too much engine for a pleasure hull.

Thanks for the inputs.

I'm not gonna trade the boat for one that already has a V8. I've had it since 1996 and it means a lot to me. But I'm not willing to spend a fortune on an LS1 swap.

I was thinking about finding an engine from a low mileage Camaro, stripping it from all unnecessary stuff, including EFI and then start building.

 

[HorizonblueDK]

Re: Chevy LS1 engine in the boat

It seems like most people are talking me away from doing this swap, which means that I HAVE TO DO IT

No seriously, this is an interesting talk. I don't think I have given a clear reason why I want an LS1 in the boat.

I would like to have a V8 in the boat because it runs smoother than the V6 and sounds better. Performance gain is also a wish, but I don't want to make a speed monster, the boat is not built for that.

I could easily find a secondhand SBC, fully marine dressed, more or less ready to drop in. But it is so damn heavy.......

Ok, take this marine SBC and add aluminium where possible; heads & intake manifold, and build or purchase a set of stainless steel manifolds to save weight.

This is also gonna cost something and take some time to do, so wouldn't it be better to find an LS1 engine from the beginning?

I'm very focused on weight saving, maybe too much.....?

 

[doyall]

Re: Chevy LS1 engine in the boat

I can think of so many cliches that really work here.

 

[thumpar]

Re: Chevy LS1 engine in the boat

If you go with aluminum you will need to add closed cooling so right there you have lost a good chunk of your saved weight.

 

[Scott Danforth]

Re: Chevy LS1 engine in the boat

It seems like most people are talking me away from doing this swap, which means that I HAVE TO DO IT

No seriously, this is an interesting talk. I don't think I have given a clear reason why I want an LS1 in the boat.

I would like to have a V8 in the boat because it runs smoother than the V6 and sounds better. Performance gain is also a wish, but I don't want to make a speed monster, the boat is not built for that.

I could easily find a secondhand SBC, fully marine dressed, more or less ready to drop in. But it is so damn heavy.......

Ok, take this marine SBC and add aluminium where possible; heads & intake manifold, and build or purchase a set of stainless steel manifolds to save weight.

This is also gonna cost something and take some time to do, so wouldn't it be better to find an LS1 engine from the beginning?

I'm very focused on weight saving, maybe too much.....?

First, with aluminum heads and intake on the SBC your only saving 40# with the LS1. That is a cooler of beer. Second, you are focused on weight saving too much - you cant see the forest because your nose is in the bark.

With aluminum, you will need a closed cooling system (added weight almost 70# worth) or need to keep everything cast iron - note the weight issue almost cancels out each other there (saving 90# going aluminum, adding $70# of cooling system). There are dual alloy SBC intakes where there are bronze water passages cast into the aluminum intake.

if you want to save weight, spend $2200 on CMI tubular headers I think they weigh #15 each compared to the heavier than a child cast iron exhaust manifolds. or about $1100 on ceramic coated aluminum manifolds

 

[Walt T]

Re: Chevy LS1 engine in the boat

I dunno, I kinda wanna see him do it. I know I might learn something

 

[Bondo]

Re: Chevy LS1 engine in the boat

I can think of so many cliches that really work here.

Ayuh,..... I'm seein' an ole work hull boat with a Hot Rod motor in it,....

A different hull could make use of the proposed motor,....

 

[Maclin]

Re: Chevy LS1 engine in the boat

A day or so ago I had typed in a paragraph with a subject something along the lines of what others have posted since then, then dumped it when I re-read Horizon's original question, being that of marinizing the LS1.

I am still homing in on the weight savings though. The boat is 18', and incremental HP increases will be more noticeable than say in a 20' to 22' boat. So I keep coming back to spending time/money/effort on a nice HP upgrade to the 4.3. It is just laying there waiting for some attention, and there is no cost in obtaining an engine to start from.

I also think starting with an LS1 then carbing it and such kind of defeats the purpose of starting with an "exotic" engine. On the other hand I also understand the allure of having an LS1 in there even in a detuned state, nice conversation starter! And to Walt's point, heck, could be good learning exercise for you to share.

 

[Scott Danforth]

Re: Chevy LS1 engine in the boat

well, I found a youtube vid of the owners boat : Draco 1800 Suntop - YouTube

Maclin, I agree with rehashing the 4.3

Here is a list of things that I would do since this is a pre 1996 motor:

Switch to vortec heads and intake. its good for 40hp on the V8, its good for nearly 30hp on the V6
run 1.6:1 rockers
drop in a 266 degree duration cam (good torque, and not enough duration to cause reversion) http://www.summitracing.com/parts/CCA-56-450-8/
Run a ventilated prop for the hole shot.

That would give a good 40-45hp shot to the existing motor without re-inventing the wheel.

Here is an article from a few years back that even has iboats own tail gunner chiming in 4.3 Marine upgrade - Hot Rod Forum : Hotrodders Bulletin Board

 

[HorizonblueDK]

Re: Chevy LS1 engine in the boat

Yes Scott, that is my boat in the video.

Another one

Wouldn't it just sound better with a V8

Actually, I installed this V6 engine some years back, it had a 4 cyl Volvo AQ151 from the factory. When they were still in production (1980s), they were available with a 5.0 V8, but most are sold with a 4 cyl Volvo or Mercruiser.

I was not aware that it is possible to drop Vortec heads on a non balance shaft V6. Are we talking about the heads that has plastic rocker covers?

From a power demanding standpoint, yes it makes more sense to work with the existing V6 engine. But I'm also focused on the smoothness and sound of the V8. And no matter what foolish stuff I put on the LS1, it will produce more power than the engine I have today, I believe.

Someone mentioned earlier that I need closed cooling on the aluminium engine. Oh yes, I will never build any inboard marine engine without....

Interesting thread with the 4.3 marine upgrade.

The weight saving with the LS1 over an SBC with aluminium heads / intake manifold, may be small, but my initial thought is that I will not save that much money compared to just buying a fine LS1 engine from a car.

I think I should sit down and calculate, to find out which option is the cheapest, all things considered......

But hey, couldn't it be fun to open the hatch and there we have an LS1

 

[Scott Danforth]

Re: Chevy LS1 engine in the boat

Wouldn't it just sound better with a V8

Not really, if you want sound, you need to go big block. however after a while open exhaust just gives me a headache.

I was not aware that it is possible to drop Vortec heads on a non balance shaft V6. Are we talking about the heads that has plastic rocker covers?

No, Vortec heads are the heads with the Vortec combustion chamber. these heads are on the 1996 and later motors. the Head doesnt care abou the block or the valve covers. GM did start labeling everything "Vortec". however you can get low mileage late model heads from a you pull it salvage yard for $25 ea. the heads, however do care what intake its mated up to.

The weight saving with the LS1 over an SBC with aluminium heads / intake manifold, may be small, but my initial thought is that I will not save that much money compared to just buying a fine LS1 engine from a car.

As we stated, you would spend a whole lot of cash to marinize it.

But hey, couldn't it be fun to open the hatch and there we have an LS1

Then do it correctly and get one of these marinized LSX motors

The 6.0 L96 http://www.gmpowertrain.com/2013_pdf/FHR_REV_6.0_Marine_010713.pdf
the 6.2 "LS3" http://www.gmpowertrain.com/2013_pdf/FHR_REV_6.2LS3_Marine_010713.pdf
the 6.2 LSA http://www.gmpowertrain.com/2013_pdf/FHR_REV_6.2LSA_Marine_010713.pdf

However you have to go thru Volvo Penta, or Mercruiser or PCM or one of the other Authorized channels to obtain.


to simply take a non J1171 complant engine and install into the bilge of a boat is an explosion waiting to happen. Not to mention that an LS1 from a car would suck water back in (reversion) due to the cam profile unless you ran dry exhaust headers.