Detecting a failed lower bearing
 

OK, my oil pump temporarily failed and i blew a lower bearing. I was going to replace the old motor, but am considering a boat i can get at a great price that is, physically and cosmetically, in better shape. However, what i discoverred with my motor is that, at low rpm and load, the boat ran fine, no vibration or knock until higher rpm and load.

So,my question: Is there a test with a motor sitting or at best on muffs that i can do to check for this (a failed lower bearing)? I'm thinking a compression test won't work, but a vaccum test might.

Any assistance/thoughts would be appreciated.

Al T

OK I have to be the first one to ask:grinser010:
how does an oil pump temporarily fail?

I think you answered your own question
no vibration or knock until higher rpm and load

More than likely You spun a bearing.

Cut open the oil filter, see if it shines.

Sorry to hear it, most of us have been there done that.

Compression or vacuum test won't tell anything about a bad bearing. If you spun or wiped out a bearing you will have very low oil pressure. If that is what happened you shouldn't even be running it.

After the engine has sat a while, You may be able to hear it knock if you have someone else start it ,And you stick you head by the engine. You will have a second or two before the oil pressure comes up to hear it....are you sure its not detonation/pre-ignition?

I would like to blame an oil pump failure on the ones I've grenaded. lol.. I've seen some of those sludge turds of bearing debris and it's not what I would say a very good feeling. I had simular symtems on the dyno last year and immeadiately pulled the engine and pan as well as all the main caps. All was fine including the filter with the exception of the normal break in debris. It wound up being a collapsed lifter. Under normal circumstances I would have more than likely found the cause with out the hassle however I was a little concerned being a new engine.

Regardless if you ran it much after you heard the knock more than likely your looking at something that's not a quick fix. Then again in this hobby it's not that often anything is a quick fix. Good luck though.

oil pump
 

Temporary failure of oil pump = ran out of oil...lol...
Anyway take off the filter and cut it open. If you see metal take the boat to the shop and also bring your wallet. If no metal you can try putting in 2 bottles of slick 50 and then top off with 20w 50 and fire it up. Let it idle on the hose for 30 min if there is little or no noise. Then take it to the lake and run the piss out of it. I have seen this work 3 of 5 times. Bought some 1 season and others 3 seasons. 1 guy did throw a rod through the block but he was already screw anyway and its usually easier to buy a long block then rebuild a non hi-perf motor.

Chris