300/440/550 '87 JS300 to JS440 engine swap

S

STOOPIDSKI

Location
PA
I currently have a '87 JS300 that im in the process of swapping out the engine to a 440 motor that I had laying around. The 330 engine was completely stock along with the entire ski itself. The 440 engine I am swapping in has an aftermarket cyl. head (unknown) and a complete Westcoast exhaust which also came with an L&S waterbox. Unfortuately the engine does not have a carb. and did not have the year correct igntion box, and the westcoast exhaust outlet doesnt line up AT ALL with the L&S water box intake. Obviously the exhaust outlets are on differnt sides of the hull as well.

Bascially I'm just running into all sorts of different issues lol which I'm trying to sort one at a time. Just curious if anyone has done this swap before and could offer some friendly suggestions or points to be aware of. Thanks
 
N2 H2O

N2 H2O

Previously Tbone550
Location
Charlotte, NC
The year of the ignition box should not matter. Aftermarket exhaust and waterboxes all line up a little differently. Most don't line up very well if they are mixed brands, but can be easily made to work with padding under the water box and different shape exhaust hoses. I really have had to wrestle with some of the waterboxes to make them fit. You need to find a new carb for the 440 motor and not use the old 300 one. The 300s came with bn34's. I would suggest a bn44 or a sbn44 if your budget allows it. You would need a 44mm manifold for either of these carbs and a spacer for the sbn. Pictures would help with some of the alignment issues.
 
S

STOOPIDSKI

Location
PA
I will post pics as soon as I can. as for the engine as it was explained to me by the man to did all the work on that engine, its a 440 bottom end with a 550 top end or vice versa... im not entirely sure. I was told it was an old school performance set up. it that anyway to truely distinguish which way it might be without pulling the cylinder head off and measuring the cylinders?

Also i had no intentions of using the old 300 carb. I do however have a bn44 (40mm) carb. but the opening on that is larger then the opening on the intake manifold which came with the engine. I assue thats the intake for the bn38 carb. Find correct bn38 carb or find intake for bn44?
 
N2 H2O

N2 H2O

Previously Tbone550
Location
Charlotte, NC
You probably have a 440 bottom end with a 550 top end. That means that you basically have a 550. I would find an intake for the bn44 and use it.


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N2 H2O

N2 H2O

Previously Tbone550
Location
Charlotte, NC
Your pipe seems to be angled a little more towards the hull than most of mine. I would just try to get the pipe and waterbox connected and then worry about getting it strapped down correctly. Most of my hoses in between the pipe and waterbox have a bend in them that angles towards the waterbox. I'll try to get a picture tonight of my Westcoast pipe and stock waterbox connected.
 
N2 H2O

N2 H2O

Previously Tbone550
Location
Charlotte, NC
Here's one of mine with the stock waterbox. It's not quite as bad of an angle as yours, but you can still see how much the hose is bent.


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N2 H2O

N2 H2O

Previously Tbone550
Location
Charlotte, NC
Now that I'm looking at the pics side by side, it looks like your waterbox is could be pushed more into the nose to make it work better.


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S

STOOPIDSKI

Location
PA
You would think lol. but its already pushed as far forward as the forward strap mount hardware will let me. the water box is already hitting that mount/screw/bracket as it sits in my picture.
 
S

STOOPIDSKI

Location
PA
Ok thanks.

Moving pass the exhaust issue now,
Any other thoughts or point of concern to keep in mind. All help, thoughts, suggestions, ideas and input is greatly appericated.
 
N2 H2O

N2 H2O

Previously Tbone550
Location
Charlotte, NC
Everything else should be pretty straight forward. Are you sticking with the stock 300 pump? It is the same as the 440 pump, but I would highly suggest an aftermarket impeller because of the mods and higher engine you have now. The 550 with a pipe will most likely cause the ski to cavitate with the stock 300 impeller.


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S

STOOPIDSKI

Location
PA
yes I plan on running the stock drivetrain set up of the 300. I have addded a nozzle wedge and mariner 2bar intake grate that i had laying around. but other then that yes: bearing housing, driveshaft, impeller, ect... all stock JS300 items.

What impeller size would you suggest? I had thought of trying the stock impeller just to see what would happen, but I know that i will definately need to upgrade it.
 
S

STOOPIDSKI

Location
PA
thank you, ill keep an eye out for one.

Another note, anyone know what the torque spec is for the bolts holding the engine bed pan to the rubber motor mounts in the hull?
 
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