300/440/550 ID on engine please, just bought another, 50 bucks...

550surf

550surf

i bought this hull and engine yesterday for 50 aud.
i need a starter stop switch and hood strap part so win win :)

amougst the rumble, was this. he said it was a 440 but today i opned it up and noticed that the pistons DID NOT have ports on them ! and its clearly a PP engine...right?

So i google the standard size diameter of both the 440 and 550 cylinders. 440 is 68 and the 550 is 75mm and i measued the cylinders and it was 75.5 or 76mm!

now the pistons only have the numbers, " 50" and a letter M. So im guessing that the pistons are .5 over the factory bore.


Is this infact a 550 engine or a 440, bored out to 550?
the hull has been spray painted black ( super poopty) so i cant see any designs, graphics for indicators.



what do we have here gentle? the number 530 can be found on the engine too if that helps...
 

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eastcoastjumper

eastcoastjumper

James
Site Supporter
Location
Long Island
A piston port 550 cylinder will fit on a 440 case.

Or it could be just .5 over 550 piston port that was swapped in.

The pistons look like they might have seen better days.
 
flgliderpilot

flgliderpilot

Location
St. Pete, FL
Looks like a 440/550 bottom end with a 550 top end, bored .5 over. Looking at the pistons, you may need to have it bored again to the next size up. Top end looks worn out.
 
550surf

550surf

cheers lads for the ID
im not sure what plans i have for this thing. was surprised to see it in this condition compared to the hull. lol it looks firebombed
 
Big Kahuna

Big Kahuna

Administrator
Location
Tuscaloosa, AL
flgliderpilot said:
Looks like a 440/550 bottom end with a 550 top end, bored .5 over. Looking at the pistons, you may need to have it bored again to the next size up. Top end looks worn out.
Click to expand...
There is no way to tell if it has been bored and what size over. Unless you can see the crown of the piston and read the etching
 
flgliderpilot

flgliderpilot

Location
St. Pete, FL
To be honest it really doesn't matter what it is now, because the pistons are shot and you need to have the bore sized to match a new set of pistons. The cylinder is probably worn near the ports and tapered, so the cylinder will probably need to be bored again if it's not to far over already.

Send the cylinder to a shop and have them order the correct pistons (whatever they determine they will need) so they can match the bore to the pistons. I just went through this myself.

You $50 engine just became a $350 engine : D

If the compression wasn't too bad (at least 130) you could just run it and hope for the best. It's a $50 engine after all.
 
550surf

550surf

it makes compression!, like you reallly have to turn it over hard by hand.
I already said to myself, " NOOOOOooooo mate !!!!! your not gona build another engne! im hunting around for a X2 or 650 so i can do a conversion.

i read one fourm and it looked quiet easy,
was lasermans post.

he sad that the 550sx hulls were the best for this project.
can i ask why???
i have an 87 hull, whats the diff?
 
flgliderpilot

flgliderpilot

Location
St. Pete, FL
The pump in the 550SX is a different design. The load is on the pump rather than the engine bay bulkhead. The 440 hull can crack at the bulkhead under heavy load unless a bulkhead brace is installed.

I'd just go ahead and try running that engine. It was only 50 bucks you don't have much to lose.
 
550surf

550surf

yeah since its a 550 im fairly interested plus i have all the parts....
ad the crank is good.

i have reinforced the bulkhead, plus the skis has a this, is this wht u were talking about?


btw, why are these pistions without PORTS!!!! did anybody notice this? they are the same as the reed value ones with the 5mm hole drilled in the tops?
 

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