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1990 90hp, broken ring after overhaul

J

Jay1234

Regular Contributor
Morning all,

Rebuilt my engine at the start of last season. Engine shop bored 030, new everything except con rods and crank. WSM pistons. Carb kits, proper break in, idle and WOT timing set. Boat ran great all year.(or so I though)
Last night I fired it up to get it ready to go in the slip. Noticed a small water leak at the bottom starboard side of the exhaust cover. Pulled cover to reseal, see that the #4 piston is damaged. Broken ring.
I won't be able to tear down for a week or 2, but when I do what should I be looking for? Could the exhaust cover leak have contributed? Just looking for ideas on how to proceed, what I could have potentially done wrong, etc.

Thanks.
 
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Used the wrong style piston ??----What angle is on the top piston ring ?----What was the ring gap?-----What was piston to bore clearance ?----What was maximum timing advance at full throttle?----What boat ?-----What pitch prop?-----Maximum RPM ?----Just finishing rebuild of a 1993 model for someone about 1 HR away from you I believe !
 
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I ordered a complete overhaul kit for the engine, pistons looked the same as the old ones. I did not check ring gap. Piston to bore clearance was checked by the machine shop, not sure on numbers. Max timing advance at full throttle was spot on 28. It is a 18' Crestliner Phantom. 5200rpm wide open.
 
Motor i just did had been rebuilt.----Broken rings on 3 of 4 pistons.----Cheap pistons ( no identification ) on them !
 
Damn, I wish I was better educated on that. The supplier sold and advertised them as WSM but the pistons definitely don't have any markings on them aside from the 030 stamp. Makes me question the rest of the kit now. Hard $1000 dollar lesson.
I will tear down and report back when I do.

Thanks.
 
I bought from a dealer out of Florida. The pistons came in plain white boxes. When I called WSM they said their boxes are blue and white and labeled. I specifically wanted to go with WSM, but I'm not sure if it's what I got.
I'm thinking maybe I messed up putting the piston in possibly? I took my time, lot's of oil, ring compressor, but who knows.
 
You do not use a ring compressor on those.----Unless it is a factory style.-----A tapered sleeve that gently put the rings in place on the wee dowels.
 
Ahh. Damn it. I guess that's probably the issue then.
I missed that in the manual apparently.
Apologize for the stupid question, but is that sleeve the same for oversized pistons?
I will order one tonight.
Thanks.
 
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Each oversize needs a different oversize sleeve.--------The sleeves make it quicker to install pistons / rings.-----You just need a small screw driver and patience to work the rings in.----Did one a while ago and it was painless !!
 
Should I use the sleeves or a small screwdriver? Would you be so kind as to point me towards the part # for the sleeve for a 3.530 piston?
 
YouTube videos showed me how to install them last year. Using a compression sleeve. You machined your own sleeves? I don't have that kind of spare time.
 
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Hurry-----Get your local friendly shop to install the pistons.------It be a simple job.-----I think I could teach the 11 year old grandson to install them.
 
Wow dude. You are a ****ing dick. People like you need to be the **** off this forum. I will get banned for this message, but I don't give a ****. It's worth it if the mods are opened up to your bull ****.

Useless.
 
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