LS Repower 2005 22V

[V12MAC]

Has anyone tried to do an LS swap in a 22v? I picked up a hull with a damaged 5.7 and the LS crate motor is just about the same money right now.
Thoughts?

[boatwakes]

Marinized or auto? We did the marinized 420HP in a jet boat, easy and reliable horsepower, marine engine depot.

[h2o-ski]

I have priced it out for my old Supra. If you go with crate engines, yes the price is comparable, mainly from the fact that GM is not producing the 5.7 SBC anymore. However if you replace only what is broken and reuse what still works, then the 5.7 will be cheaper.

[UNSTUCK]

I've done a few LS swaps in various non GM vehicles and thought about doing one in an old MB I had. Would be a fairly easy swap, and junk yard cheap. I'd probably go the route of keeping it automotive for custom tuning. Easy to run Hydrophase cruise control with drive by cable. Tune the ECM so it thinks it's running a manual transmission. EASY horsepower.

[h2o-ski]

That was my thought Unstuck. Keep it automotive as much as possible, though what is holding me up the cost of the flywheel, bell housing and then the manifolds. If you can find early 03 or 04 (I think) LS's they were still throttle by cable, would make it easier.

[chpthril]

Not sure I follow why a street engine is needed over a marinized engine.

[h2o-ski]

The main reason is cost. I can go to a automotive junkyard in the area and get a motor; not so much luck on a marine junkyard. In my rough pricing I could drop an iron block LS from a junkyard in place of a SBC for around 3K. Main difference between a marinized engine and automotive is head gaskets, core plugs and ecu. Best I have been able to find on new marine engine is 12k, less if you can reuse parts you already have.

[boatwakes]

If you have the time to chase the little things, and enjoy headaches, go auto with closed loop EFI (requires a sniffer in the exhaust and no marine exhaust manifolds have a port for them so that becomes custom). The marinized versions run stand alone open loop efi with custom fuel mapping. However, programming a custom open loop fuel map allows for added weight and prop sizes but it just seems a bit excessive for a non-race application. However, its tons of fun to do.

[V12MAC]

My plan is a turn key crate LS from Merc. Automotive electronics are a no go for me as I want everything to be ignition protected / spark arrested and safe.

My 5.7 runs but the previous owner had a raw water leak that trashed everything with salt water.

[V12MAC]

Planning on ordering the motor this week. Can the stock trans and V-drive hold a 6.0 or should I go w the smaller 5.3?

[h2o-ski]

I have been wrong but Mercury has not released a marinized version of an LS. The 6.2 they have now is SBC based. Now all other marinzers have pretty much moved to LS

In regards to the next question, yes they should be able to just make sure that the bellhousing bolt patterns match what ever is changing, though after some reading the bellhousing bolt pattern is the same with different holes being used.

[chpthril]

I might be wrong, but I thought Merc was casting their own engines v's hanging their gear on a GM marine block.

[boatwakes]

Sorry been doing other stuff. NO MERCRUISER MARINE EFI SYSTEMS ARE COMPATIBLE WITH AN LS ENGINE. Any LS EFI marine swap is only possible through Marine Power or PCM (Crusader) and if you use another block, you must MAKE SURE THE CAMSHAFT PROFILE IS EXACTLY THE SAME AS THE PREVIOUSLY MENTIONED ENGINES! Exclamation point. Exclamation point again.

I meant automotive as far as a junkyard block from a truck or long block from GM. There's tons of info I think you should research prior to investing in putting an LS into the boat. Any way you look at it, it should cost between $12-15K to correctly replace the engine currently in you boat.