LORDDiESEL

Guys, i'm looking for a aluminum 5.3L for a jet boat project. LM4 and L33 are on the hunt list. Any reason a LS4 wouldn't work? I know it has a different bellhousing, but other than that, the rest of the motor is the same, correct?

Thanks guys.

bigmandengo

iTrader: (21)

The hardest part will be finding a jet boat bell housing for that pattern.

lsxRanger94

I think the crankshaft is shorter in length also. The water will corrode the aluminum if directly cooled. That is why boat engines are usually cast iron. try a 1999 6.0: cast block and heads but aluminum water pump.

LORDDiESEL

Can't take the extra 100lbs

Running a heat exchanger. Need to find more info on the ls4 if i can't find the others listed.

lsxRanger94

Look at an Impala SS. Accessory drives are different due to space. bellhousing patten is a 60 degree v6 pattern. cams are the same style as rwd engine and you can use a ls1 style intake. Heads are basically the same.

check this out has a ton of pics.

https://ls1tech.com/forums/conversio...peed-swap.html

fieroguru

iTrader: (1)

The LS4 uses the GM Metric (FWD V6) bellhousing. Here is the bellhousing side of an LS4 block:


There are Metric engine to SBC transmission adapter plates for about $65 that are around 3/16" thick.
http://www.speedwaymotors.com/Chevy-...ates,3280.html

The big issue is the starter. Due to the smaller Metric bellhousing, a 142 tooth flexplate is used (not the typical LS(x) 168 tooth). With the flex plate being that small, there is no easy room on the engine side for a starter to fit, so it only came with a transverse FWD transmission with a built in starter mount. So to use the LS4 in something else with a different transmission, you need to build a starter mount like this:


From there, the front accessory drive is very compact (close to the block), but very W...I...D...E with the coolant inlets/outlets coming in from the bottom. Here is a pic showing all the accessories and belt path:

This one better shows the coolant inlet/outlet locations:


The LS4 only has "some" of the engine mount bosses that the RWD blocks have (may or may not be an issue depending on mount setup):
DS of block:


PS of block:


The Camshaft sensor on the timing cover is about 90 degrees for all others, so you either have to run the LS4 ecm/calibration (E40 & E67) or swap timing covers and run another calibration:





The LS4's will accept any LS(x) camshaft, only come with the 243/799 heads, but many of the LS1/LS2/LS6 car intakes will not clear the LS4 water pump if you install them with the TB on the accessory side.

They are however, the cheapest aluminum block LS engine you can buy.

LORDDiESEL

Awesome! Thanks for the schooling, guys! I'm going to add this engine to the short list. Looks like the best bang for the buck out there. The jet drive connects with a drive shaft that bolts directly to the back of the crank, so the Bellhousing isn't a problem! I'll make my own starter and engine mount like in the picture.....

LORDDiESEL

This is the aluminum boat i'll be building from cutting files....




And here is the boat that inspired it....

fieroguru

iTrader: (1)

That starter setup and the aluminum boat looks like a really fun project!

tonypaul

iTrader: (2)

You can run a truck intake on the LS4 without any mods and you could use a Microsquirt for your engine management since you have no trans to control. Also you could swap out the DoD/AMF LS4 with a truck cam, all these items are very inexpensive.

99MedBlueBird

Hope you're okay with the starter not being engine block mounted in the ls4

LORDDiESEL

That sounds good! Where's the best place to learn how to use the microsquirt?

tonypaul

iTrader: (2)

[QUOTE=LORDDiESEL;18373937]That sounds good! Where's the best place to learn how to use the microsquirt?[/QUOT

Just about everything you need to know is here: http://www.msextra.com/
anything else I should be able to help you out on. Im running a Microsquirt on a turbocharged LS4 in my Lambo Diablo kit car....

Also you can do a search for Denmah here on the forum he has a how to wire up a Microsquirt as well as a start up tune...

LORDDiESEL

^^ Awesome! Thank you very much, tony.