toddk

I'm replacing the OEM harmonic/crankshaft balancer with another OEM balancer, and in my searching here had a hard time finding all the information in one place. I reviewed both the 2002 and 2000 FSMs as a basis for this info.

OEM balancer (2002) P/N 12560115
OEM balancer weight "short", 0.5" P/N 3890192
OEM balancer weight "medium", 0.75" P/N 3890193
OEM balancer "long" weight is not available - use two shorts

The stock balancer has 12 holes evenly spaced at 30* intervals around the perimeter. They are 1.01" deep, and 0.25" diameter. Additional shallower holes may be found for zero-balancing the unit itself.

If you have an Automatic or an F-Body, there should be no balancer weights in any of the 12 holes. If it's a manual C5, you need to scribe the crank & balancer relative positions before removal, and inspect for weights.

Inspect the 12 holes for weights. Measure the amount they are recessed in the hole to determine the size of the weight in that hole.

• Nearly flush 0.011" = Large weight = 2 Small weights.
• 0.263" = Medium weight.
• 0.512" = 1 Small weight.

Old balancer with one large weight, marked in crayon at 9 o'clock:



New balancer with no weights installed, but 8 extra zero-balancing holes:



Two of the 0.5" small weights. They weigh 3g each, and are driven in with a punch. The old weights will not come out without drilling.



Align the old & new balancers using a common reference point (the 2 o'clock arrows in my pics), and drive in the new weight in the corresponding hole of the new balancer. Mark the new hole(s) with crayon. Install the balancer matching the marks scribed upon removal.

Hopefully good for another 10 years!

Todd

baxsom

i would say just get a powerbond and not worry about matching weights or reference points

lucky131969

So what does Powerbond do different, that this procedure is not necessary?

lucky131969

Great summary sir. Most will come up with 100 reasons why it is not needed, but I certainly appreciate it.

toddk

Thanks Lucky. For the crowd who likes to stick with OEM parts, some of the details were harder to find. I wanted to pull it all together for others who are attempting the same thing.

I wasn't trying to address the aftermarket balancer options. Most don't have the provision for these weights. A 6g imbalance would not even be noticable if you're putting in a lopey cam.

Todd

thbwlZ

very nice

Just more evidence of factory engine build hot balancing procedure.

It's only unnecessary if you don't want to maintain your factory engine balance

vettenuts

Curious where you found all of this information as I don't recall this level of detail in the service manual when I reviewed it a few years back. Then again I may have just missed it

Eric D

Good question! The answer, it really isn't in the manual. This is part of the reason there has always been a large amount of confusion about the balance of the LSx engines over the years.

thbwlZ (Tommy) is taking on a big task of putting the RIGHT information about the LSx balance into a single inclusive write-up that I believe he plans to share on this forum. He has worked on this for over a year now, not any easy task. I am really looking forward to his write-up. I personally know that he has taken a lot of his own time and has contacted the proper folks to insure as best as one can the right information for his publication.

Todd!

Excellent post! Thanks for sharing and your photos too... Very good information...

m6 c5

Nice write up, short simple and to the point.
If only it was pinned from the factory...

fendermender

Would have been good to know this before I did mine. I did the ones in the flywheel but had the balancer off before I learned about this. I don't notice any vibration so far.

lucky131969

Actually gentlemen, it is a combination of information directly from the service manual, and the parts manual.

Eric D

I stand corrected.

fendermender

Anyone know why this was an issue with the manual shifts and not the automatics?

lucky131969

I think Eric is best qualified to answer that.

m6 c5

Doesnt an automatic have much more weight in the drivetrain? They have to have more friction as they have more parasitic loss so it could dampen it more.