Harmonic balancer/main crankshaft pulley

[zunibee]

Today I started hearing a noise like there was loose metal making a clinging noise. I opened the engine compartment and could see something on the harmonic balancer/main crankshaft pulley.... it is a metal ring about two inches in width that is loosely spinning on the harmonic balancer/main crankshaft pulley.

The engine seems to be running fine so I'm not sure what this ring could be. It seems like a weight of some kind but its spinning freely. Is this normal?

Jay

1997 Bayliner Ciera 2355 SE
Mercruiser 5.7
Alpha One

 

[muc]

Re: Harmonic balancer/main crankshaft pulley

No
You need a new one
Good Luck Muc

 

[zunibee]

Re: Harmonic balancer/main crankshaft pulley

Thanks for the quick response. I need a new Harmonic balancer? I read where the harmonic balancer can break in two...I thought that is what might have happened.

Should I not operate the boat until it is replaced? Had plans for tomorrow but don't want to run it if it will do damage. It ran real good today but we brought it in shortly after seeing the spinning loose piece.

Jay

 

[zunibee]

Re: Harmonic balancer/main crankshaft pulley

You guys are great. Thanks for the help.

Is this something that is available at an auto parts store like autozone, napa etc? Easy to replace?

Jay

 

[Bt Doctur]

Re: Harmonic balancer/main crankshaft pulley

1 hr at the most to fix it, using the proper puller is a must.
Remove the center bolt from the crankshaft, remove the 3 pully bolts, remove pully and re-insert nose bolt .The bolt protects the threads in the crank.using the puller ,remove the rest of the balancer, remove nose bolt.
Go to the store and get a longer bolt/threaded rod is easier) that is the same thread as the crank bolt,length really dosent matter 3-4 inch.Start the new balancer with this longer bolt using spacers as it goes in untill it is fully seated,(you`ll feel it ).
replace pulley, install nose bolt and tighteen, install belts.

 

[zunibee]

Re: Harmonic balancer/main crankshaft pulley

Thanks for the great instructions! My son has the pulley puller and after reading your instructions he says it will be no problem.

One final question. The engine is a Mercruiser 5.7 liter. What is the comparable auto engine? Need to know what to engine to tell autozone when I'm looking for the harmonic balancer.

Thanks again to all. I'm glad I found this forum!

 

[Zackman]

Re: Harmonic balancer/main crankshaft pulley

It's a GM 350.​

While your at the auto store, you can get the installer, which makes it easier. Usually you put down a refundable depost, which you get back when you return the tool.​

Before you start make sure you have plently of room from the balancer to the first obstecale so you can remove and install the balancer.​

 

[flargin]

Re: Harmonic balancer/main crankshaft pulley

Autozone and others will loan out the HB pullers, beat the heck out of buying them to use once!

May need some PB Buster (rust buster) soaking for a little while to help.

agreed... dont run it! you will have a lot more problems if you do

 

[zunibee]

Re: Harmonic balancer/main crankshaft pulley

We took off the old harmonic balancer and it my son went to autozone and advanced auto parts. They can find a balancer that is for the GM 350 but the 6 1/4 diameter one looks different than the one we have. If it is for a 350 GM and it's the right diameter is it the right one even though it looks different than the old one?

 

[maxxman04]

Re: Harmonic balancer/main crankshaft pulley

GM uses different diameter/width balancers depending on the actual motor size, AND THE YEAR OF MOTOR. you must get the right one. 6 1/4" is generally a 305, not 350, BUT THIS ALSO DEPENDS ON THE YEAR OF MOTOR, NOT BOAT. if it's unclear of motor, you can use the serial number to narrow down, or even the block number if you can see it. but it is a must that you get the right one back on, otherwise the balance of you crankshaft will be off, which will eventually result in a blown motor.

 

[gadget73]

Re: Harmonic balancer/main crankshaft pulley

Yeah, that balance is really important. I've seen snapped crankshafts from using a bad or wrong balancer before. Knew someone with a 302 that sheared the crank clean in half when the balancer let go while passing someone on the highway.

 

[zunibee]

Re: Harmonic balancer/main crankshaft pulley

Thanks to everyone for the help. We found the exact same harmonic balancer at autozone and got it on this afternoon. Had time to get the boat out for a test run and it seemed to run great!

Thanks again for all the help.