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30hp overhaul

F

fin

New member
Hi All
Its been a while. I scrubbed the rings on my 1992 Nissan 30hp NS30A3.
The engine was running great till yesterday I was running at full throttle for about 4 miles then noticed the power falling. That's when I realized the water pump was not pumping. It will still crank but the lower cylinder has 30psi time for rings. I'm good at rebuilding engines.
What parts besides rings and gasket shall I need?
Where is a good place to get them?

Thanks
Fin
 
Parts are available from any dealer, including me.
346010052M GASKET, CYLINDER HEAD $54.20
346000110M PISTON RING 2ND (STD) 25/30,40/50D $9.12 each
361873220M WATER PUMP REPAIR KIT 25C-40C $72.98

You will need to determine whether the block is OK as is, or if it will need to be over bored by 1/2 mm (costly, and would require OS pistons as well)... also whether any other bits need replacing as you discover their condition during disassembly.
 
pvanv said:
First measure the bores to see if it needs it. Usually doesn't.
Click to expand...

I've decided to go ahead and overhaul the engine. I checked the pressure, The top cylinder was 60# the lower was lower was 23#. On removing the head I discovered the top cylinder was firing some the lower was not working at all. I miked the lower sleeve and found it to be out of round. I have suspected the upper and or lower crankshaft seals were worn. Its time for an overhaul. There is a local shop that will bore the block for $30 a hole. I saw replacement sleeves somewhere but can't find it now.
Is there any benefit to replacing the rod and crack bearings on a high time engine if you can't find anything wrong? If not all I'll need are pistons, rings, gasket kit.
Anyone know the standard piston diameter?
 
The crank is pressed; the rod bearings are captive. If you need bearings, you need a whole crank kit.
3P1000691M CRANKSHAFT ASSY (ALSO NEEDS 9311211600M) $498.65
9311211600M NUT, RH (CLOCKWISE) SB #04-012 $1.94
346000043M PISTON (.5MM O.S.) 25/30 $72.98 ea.
346871240M PISTON RING SET (.5 O/S) $46.59
3C8000210M PISTON PIN $8.10 ea.
3A1871214M POWER HEAD GASKET SET $77.22
 
pvanv said:
The crank is pressed; the rod bearings are captive. If you need bearings, you need a whole crank kit.
3P1000691M CRANKSHAFT ASSY (ALSO NEEDS 9311211600M) $498.65
9311211600M NUT, RH (CLOCKWISE) SB #04-012 $1.94
346000043M PISTON (.5MM O.S.) 25/30 $72.98 ea.
346871240M PISTON RING SET (.5 O/S) $46.59
3C8000210M PISTON PIN $8.10 ea.
3A1871214M POWER HEAD GASKET SET $77.22
Click to expand...
Thaniks for the response,
AreWiseco pistons and rings as good? Don't mind paying more to be safe.
Another question- When I overhauled my zx2 engine I shaved the head to increase the Compression ratio and fuel economy. Would it be possible or beneficial to do that with this 2-strike,ns30a3?
http://www.warehouseboatparts.com/product/Wiseco/4379199-M/3157P2/020-Oversize-Piston
 
As a dealer, I try not to get into aftermarket bits, so I can't speak from experience about the Wiseco pistons. Yes, you can mill the head; If you do, you will probably end up running premium fuel, but it should be fine as long as you don't go crazy raising the CR.
 
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