1997 4.3GL Temporary Knock

[Jprevat]

I'll pick up the stethescope today and see what I hear. I fired it back up when I got home yesterday afternoon on the hose and it was right back to being completely quiet again. I'm going to call the builder today and see if he replaced the rear bearing for the balance shaft when he was rebuilding.

 

[Jprevat]

When I first install the engine I had two flywheel bolts back out just enough to make noise and they made noise hot, cold, it didn't matter. The drive shaft alignment tool slides in with two fingers worth of pressure and has even marks all around.

 

[Jprevat]

Ok guys, I finally got a chance to run it today. I got it to produce the knock and took the stethoscope around the engine to see what I could hear. The noise is definitely coming from up front and I got the best sound out of the top port bolt on the timing cover.

Is this all pointing to the balance shaft?

 

[alldodge]

Starting to seem so, but should be able to determine what it is by removing the timing cover

http://www.mercruiserparts.com/bam/subassembly/31515/1937/160

 

[Jprevat]

I guess that means it is time to get the puller out for the damper. I'm assuming that if there is any play then it needs to be pulled?

is there any reason why the mercruiser part is preferred over the acdelco version? They are about $100 different in price is why I ask.

 

[alldodge]

I would by the AC part, and hey Scott Danforth what you think about the sound

 

[Scott Danforth]

didnt see a new vid. however to answer the OP's question, get clevite bearings from your local napa / engine builder. get Melling gears and timing sets from the same guy (GM buys the parts from Melling https://www.melling.com/parts-lookup/)

cut out both Mercruiser and GM

believe the 2nd gen balance shaft parts are
Melling BT5452 timing chain tensioner
Melling 3-8MMSRH72S Timing Chain Set
cloyes gear 2555s balance shaft gears (GM12513234)
cam is a Federal Mogul CS1572

Here is the GM parts blow up https://www.gmpartsdirect.com/oem-parts/gm-gear-12513234

 

[Jprevat]

Thank you very much. When the weather improves here I will get to pulling some things and see what I find.

 

[Jprevat]

Just thought I should post the final verdict. Turns out the flywheel and coupler are supposed to have lockouts but whoever rebuilt the original motor didn't use them or loctite. So needless to say they had backed off just enough to leave enough slack to make the noise but not enough to move it by hand so one problem solved and on to the a couple new ones.

Thank you all for the help. I really appreciate it.

 

[alldodge]

Cool, thanks for letting us know. hope your next issues are small

 

[Jprevat]

I hope they are just oversights on my part when I pulled the engine but I'll be starting a new thread for those.