Can't Win For Losing

[justinteoc]

So after installing my freshly rebuilt 3.0 Engine i hear a slight knock towards the back of the engine after using a home aid stethoscope I finally pin pointed it to the flywheel housing, so I decided to pull the foot off and check gimball bearings and found that those are in great shape. I started the engine with the drive off and the noise isn't there, the shaft looks great but it must be slack in the hub that Bolts to the flywheel, doesn't look like it but I didn't even think to check it while I had the engine out,
Does anyone know what that thing is called and where I could get one from or any other ideas where this knock could be coming from, it's a 3.0GSMLKD and also the noise is much louder when the engine is at a low idle, if you rev it just a little it goes away and doesn't make any noise 1,000 Rpms or above. Thanks in advance!

 

[Bondo]

Ayuh,.... The splined thingy on the motor is called the coupler,.....

I'd sooner think yer noise is comin' from the drive,.... is it fulla oil,..??

 

[justinteoc]

Yessir it's full of clean oil as I changed it last year, and if I take the stethoscope to the back of the boat I can't hear any tapping at all, it's only if I stick the hose (stethoscope) up inside the flywheel housing under the spinning flywheel.. I'm going to pull the engine back out today and check everything a little better, seems like when I get one thing sorted out 2 more pop up..

 

[bruceb58]

Did you check the gimbal bearing alignment after you changed the engine?

 

[justinteoc]

No I didn't check the alignment but I'm gonna buy the tool to do that with or have one made by the specs on the notes on this thread. It could be the problem, I put the boat on the water today and god the knock gets way worse under power, it doesn't go away anymore, I'm sure it's coming from somewhere in the flywheel housing and very well could be the alignment, it looks ok and the shaft fits in with ease but something is going on and it's not good. Oh the worst part I just found out is I'm also getting milky oil, but the engine block held 15lbs of air pressure overnight last night.. new manifold and riser so I'm at a loss there as well, about ready to cut my losses and find another boat

 

[bruceb58]

Hope your coupler hasn't been damaged.

 

[justinteoc]

Well I took everything back apart yesterday afternoon and come to find out the noise is still there even with the drive removed, it's much quieter but still the same noise, obviously with the drive turning it's under a light load and making the noise louder, I removed the shaft from the drive by taking apart one of the u joints and the engine seems to be in alignment, the coupler fits the shaft very good so the knocking must be coming from the engine itself, come to find out the guy at the machine shop lost my original connecting rods and "supposingly" found our that 350 chevy rods are the same, I think they are more norrow since they share a journal on a v8, I feel like the rods are slapping back and forth in the crank journal.. Idk, Then I can't figure out the water in oil problem, looks like I'm gonna be looking for. Engine, but then again I'm not spending 3k on a 3k$ boat.. just doesn't make sense, I'll be in the market for a new boat with a 4.3 engine and mercruiser outdrive.. at least I can find 4.3 engines for less than 3k

 

[bruceb58]

You can't use an input shaft to check alignment.

 

[justinteoc]

May I ask why not? I greased it, slid it in and it seems even.. but I'm not sure just asking a question.. what's the diff in that and a line up shaft?

 

[bruceb58]

The shaft does not have splines and will bind if the alignment is off more than just an input shaft. You can also read the grease marks that the splines leave on the alignment tool to fine tune the adjustment. With an input shaft, you have no idea if you need to move up or down.

 

[justinteoc]

I even started the engine with the shaft inserted only and there was 0 wobble or shake, seemed to be perfectly inline

 

[bruceb58]

Then maybe it's in alignment. You still want to check it with an alignment tool.