Harmonic Balancer, what's the deal?

[TampaRiv]

Hello Gents,   

 

      As you know I got my '63 Teal Mist started a couple of weeks ago.  There was a gawd-awful noise coming from below, and I realized that the crank pulley/harmonic balancer was as loose as a goose down there. As I went to take the thing off, I found the crank bolt was tight, but the pulley wasn't tight against the crankshaft.  It was weird.   Then as I sift through the exhaustive receipts from the previous owners, there seem to be at least 2 or 3 receipts for....you guessed it...harmonic balancers. 

 

    So, here are my questions of the day.....

           *Why harmonic balancer instead of just a simple crank pulley like every other car I've owned?

          *Is the 401 somehow out of balance by design, and therefore needs a balancer?

          *My pulley/balancer looks OK, it just appears that there's a washer missing,  allowing the damn thing to spin in a clanking wobbly orbit.

   

   Thanks guys for your help, I appreciate it. 

          

[telriv]

Most ALL engines have some kind of harmonic balancer to help reduce harmonics. IF the balancer was loose you may ALSO have a front crank snout that's been worn lope sided & will ALSO need another good used crank.

I could go on for days typing with one finger about damage done from harmonic balancer bolts lose & the incorrect washers installed.

 

Tom T.

[petelempert]

I believe a common cause for this problem is that the bolt at the balancer and snout of the crank are not torqued to proper spec. It takes 220 ft/lb. I think a lot of mechanics don't know that and just get it as tight as they can with a conventional wench. At that torque its not unusual for the entire rotating assembly to move so you need to devise a way to lock the crank so it won't turn. If an un-knowing mechanic tightens the balancer nut at less than 220 or until the motor spins then quits, it will probably come loose. The effects of a loose balancer can be significant, primarily damage to the crank. If it were me, I'd get a new bolt/washer combination from Centerville Auto Repair (nailhead specialists), inspect the balancer and crank for damage(if OK), use a tiny amount of Loctite Green and borrow a big torque wrench that can hit 220. It might work out. It happened to me and boy does that motor run bad with a loose balancer. I survived. PRL

[TampaRiv]

Thank you Pete for the input, it's most helpful.  Here are a few photos of the unit I removed.

[demon452]

Looks a little chewed up on the inside. Kinda difficult to see from the pic. Would definitely look at the crank. Do you have a dial caliper? If so check crank snout and id of balancer.

[RivNut]

Check Russ's website for a new bolt and washer.  He also sells a repair sleeve for the crank.

 

 

Others may have these for sale as well.

[telriv]

Ed,

 

  That's NOT a repair sleeve for the crank but for the harmonic balancer IF the sealing surface has a groove in it from the seal.

I ALSO have those parts needed, even a good used balncer.

Tampa Riv. Need a picture from the front of the balancer looking at a straight shot at the keyway groove. 1st. clean off ALL the grease in side & out.  Then take a pic of the nose of the crank at 90* intervals especially the keyway slot.

 

 

Tom T.

[TampaRiv]

Thank you Tom.  I will clean up the unit tomorrow and get some good photos of the keyway.  I really appreciate your help.  My email is  richardreau@hotmail.com.

 

Rich

[1965rivgs]

9 hours ago, TampaRiv said:

Thank you Pete for the input, it's most helpful.  Here are a few photos of the unit I removed.

This balancer is junk. The keyway is broken out into the sealing surface. I can imagine what`s left of the keyway itself isnt pretty as well. Also looks like there is a crack eminating from the keyway.

Tom Mooney

[TampaRiv]

Thanks Tom.  So, where do I buy another unit?  Any special considerations in picking one out?

[1965rivgs]

24 minutes ago, TampaRiv said:

Thanks Tom.  So, where do I buy another unit?  Any special considerations in picking one out?

  Tom T. says above he should have one. If for some reason he cant help you out I have one. You basically want one with a decent sealing surface (even though that can be dealt with via a repair sleeve), a good keyway that hasnt been oversized from running loose and what appears to be good rubber between the inner and outer half.

  Better check the nose of your crank as has been suggested...that may be why the balancer has been changed repeatedly.

  Good luck!

Tom Mooney

[arnulfo de l.a.]

So the harmonic balancers between 401's and 420's are interchangable? I was under the impression that they were not being these motors are balanced with the harmonic balancer. Good to know they are interchangable.

[KongaMan]

16 hours ago, 1965rivgs said:

This balancer is junk. The keyway is broken out into the sealing surface. I can imagine what`s left of the keyway itself isnt pretty as well. Also looks like there is a crack eminating from the keyway.

Tom Mooney

Barring any structural defect or unseen damage, that may be fixable.  Put a bead of weld over the broken area, mill it flat to create a good sealing surface, cut/ream the hole to remove any overhanging weld, and recut the keyway.

[1965rivgs]

2 hours ago, arnulfo de l.a. said:

So the harmonic balancers between 401's and 420's are interchangable? I was under the impression that they were not being these motors are balanced with the harmonic balancer. Good to know they are interchangable.

Dont know where you are seeing a reference/recommendation to interchange in this thread? Maybe I missed something....the original part numbers are different which makes sense due to the difference in reciprocating weights. Having said that, back when I was a kid and didnt know any better or have any other options (pre-internet!), I used/mixed up the balancers and didnt experience any catastrophic results...but the goal was to keep a driver in service, not to fine tune the engine balance,

Tom Mooney

[telriv]

Any 401/425 balancers that you look at will have different balancing pins put in different places on the outer ring. Some may even have drill marks in the OD or ID of the balancer.  All the balancers have different balancing required depending on how the fine balance turned out at the engine plant. Even flexplates have holes drilled in them for the final fine balance of the engine assembly.

[1965rivgs]

2 hours ago, telriv said:

Any 401/425 balancers that you look at will have different balancing pins put in different places on the outer ring. Some may even have drill marks in the OD or ID of the balancer.  All the balancers have different balancing required depending on how the fine balance turned out at the engine plant. Even flexplates have holes drilled in them for the final fine balance of the engine assembly.

Yes, each engine is unique in terms of final balance but before final balance I think the 401 and 425 balancers start with different counter weighting. I seem to remember you and I comparing 401 and 425 balancers long ago and noting cosmetic differences in the basic counter weighting....same with the flex plates...or, maybe it was just a cool dream!

Tom M

[arnulfo de l.a.]

5 hours ago, 1965rivgs said:

Dont know where you are seeing a reference/recommendation to interchange in this thread? Maybe I missed something....the original part numbers are different which makes sense due to the difference in reciprocating weights. Having said that, back when I was a kid and didnt know any better or have any other options (pre-internet!), I used/mixed up the balancers and didnt experience any catastrophic results...but the goal was to keep a driver in service, not to fine tune the engine balance,

Tom Mooney

My bad , poorly worded question. Can a used harmonic balancer  from one 401 work on another 401 without any adverse affects ?

[demon452]

In theory its possible it may work it all depends. Could create more damage. Because weight/balance has everything to do with it. Like stated some have drill spots etc..Think of it as a wheel weight or driveshaft. Different placement affects the balance speeds/vibration. May or may  not affect idle but can and will affect a certain rpm or possibly throughout. Vibration etc..

Edited March 28, 2019 by demon452 (see edit history)

[TampaRiv]

     OK guys, so if I understand this correctly,  each balancer is custom balanced to each crankshaft?  And how on earth would it be possible to know if any replacement balancer would be compatible with any given crankshaft, until you install it and put everything back together and start the engine?

 

    I see that the CARS guys (oldbuickparts.com) will rebuild my old balancer for $154.  That seems like a decent price.  But, given that I don't think my current balancer is original to the car, then what?  Sorry to be a PITA, I just don't quite understand all of this.

   

[telriv]

IF you send that balancer to be rebuilt I think it will be rejected

[petelempert]

I'm an optimist. I think it can be repaired and rebuilt. IMHO, it's better to try and stick with the balancer that came with the motor since it was tuned out of the factory with that unit. Conversely, if that balancer is not original to the motor, it's a different consideration. If the car ran well with this unit until it got loose, I'd focus on repair. Otherwise, send it to a balancer shop and tell them you need to match this units spec but with a new one. Just buying a replacement balancer off the shelf is a little risky since there is mo telling how its been tuned...if at all. I do not think the 401 is interchangeable with the 425. By the way, the specs on these motors is important, but there's no need to get all doomsday about it. A finely tuned balancer is life and death critical on a high revving nitro methane burning dragster. On a low revving nailhead, not so much. PRL

[KongaMan]

16 minutes ago, petelempert said:

I'm an optimist. I think it can be repaired and rebuilt. IMHO, it's better to try and stick with the balancer that came with the motor since it was tuned out of the factory with that unit. Conversely, if that balancer is not original to the motor, it's a different consideration. If the car ran well with this unit until it got loose, I'd focus on repair. Otherwise, send it to a balancer shop and tell them you need to match this units spec but with a new one. Just buying a replacement balancer off the shelf is a little risky since there is mo telling how its been tuned...if at all.

 

Spot on.

 

Although I believe that this balancer is a replacement, I'd absolutely go for repair first.

[arnulfo de l.a.]

5 hours ago, petelempert said:

I'm an optimist. I think it can be repaired and rebuilt. IMHO, it's better to try and stick with the balancer that came with the motor since it was tuned out of the factory with that unit. Conversely, if that balancer is not original to the motor, it's a different consideration. If the car ran well with this unit until it got loose, I'd focus on repair. Otherwise, send it to a balancer shop and tell them you need to match this units spec but with a new one. Just buying a replacement balancer off the shelf is a little risky since there is mo telling how its been tuned...if at all. I do not think the 401 is interchangeable with the 425. By the way, the specs on these motors is important, but there's no need to get all doomsday about it. A finely tuned balancer is life and death critical on a high revving nitro methane burning dragster. On a low revving nailhead, not so much. PRL

Thanks for the clarification ! I also think that is a great idea to take it to a balancer shop to try and duplicate.

[Turbinator]

On 3/26/2019 at 8:04 AM, telriv said:

Most ALL engines have some kind of harmonic balancer to help reduce harmonics. IF the balancer was loose you may ALSO have a front crank snout that's been worn lope sided & will ALSO need another good used crank.

I could go on for days typing with one finger about damage done from harmonic balancer bolts lose & the incorrect washers installed.

 

Tom T.

Or no washer installed. And the nut on the snout not torqued to specs. A shop almost ruined my car because of incompetence. My balancer came off while I was driving. Costly second repair.

Everything is fine now. I was lucky.

Turbinator

[TampaRiv]

Thanks guys,

 

   I've gotten some great advice for everyone, and now have a replacement balancer ready to install.   I will torque to spec so hopefully the damn thing won't come flying through the hood or the floor board!

[RivNut]

Don't forget that 1/4" thick special washer or you'll be up the creek in no time.

[Garett]

64 Riviera. So....In my infinite brilliance. Replaced the timing chain, cover, water pump. Went to reinstall the harmonic balancer and the keyway is worn. Im not so much worried about the pulley boss although it might affect balance slightly. Of course it it reassembled now. The key is slightly worn and of course I didnt address it while it was off. Think I can run it as is? How would I even try to fix it? Weld it up and recut the keyway?

[1965rivgs]

   Dont run that...it will loosen up. Easiest, and probably least expensive pathway is to find a replacement

Tom Mooney

[telriv]

That pulley is JUNK.  You can see the elongation of the keyway, the broken external part where the fan belt pulley rides.

You can see in the photo only one balance pin, may be more.  Can also see the drill marks for the critical fine balance.

I can see 5 drill indentations, may be more. All I can see in pics.

[telriv]

Forgot. You must closely inspect the snout of the crank ALSO in that area as well as the key itself.

[Seafoam65]

               If that balancer hasn't ruined the crankshaft already it soon will.........don't drive it anymore till you tear it down, inspect the crank

snout and key and replace with a good balancer.

[XframeFX]

Final Trim Balance Specific for each engine is done on the harmonic balancer AND the Flexplate? I've noticed that on other engines and thought it was a static trim for the flexplate only. What about the Dynaflow, no ring? In the Nailhead's case, the Flexplate stamping includes the external offset balance. So, the way I see it, the crankshaft along with both the harmonic balancer and the flexplate are dynamically balanced before engine assembly. No trim balance.

 

Although harmonic balancers and flexplates can be replaced, they wouldn't include that dynamic balance of the 3 components specific for that engine. Further more, used parts would include a balance specific for another engine. Not a huge difference, but not dead-on as when new. I imagine if we could go to the GM Parts Counter and order a new balancer, it would have a static balance for that item only (including the offset that the Nailhead requires).

 

I purchased a Flexplate from Centerville Auto Repair with a chunk of sheet steel tacked on for the external balance. When I asked what the balance process was, thinking the offset was added after a static balance, he blurted out "we never had one come back"!

 

Anyway, my head hurts!

Keep at those Harmonic Balancers until you get it right. No catastrophic failures!

John B.

 

 

 

 

[XframeFX]

I just checked 1963 and 64 Shop manuals sections 2-11 and 2-27. Not much in the 64 but the 63 manual claims a dynamic balance upon assembly and a final balance when in operation. It shows an image of adding weights  to the Dynaflow torque converter for the final balance.

Section 2-27:  "Completely assembled engines are also given a running test and balanced to very close limits by drilling the flywheel or by adjusting converter balance weights as required".   Also, an underlined Note stating a trimmed torque converter cannot be used with another engine. So remove all weights especially when a previous repair did not mark the orientation on disassembly? Flexplates use weight removal instead of weight addition as on the Dynaflow.

So a test drive is a must with Harmonic Balancer and Flexplate/Torque Converter replacement!

 

John B.

[1965rivgs]

15 hours ago, XframeFX said:

I just checked 1963 and 64 Shop manuals sections 2-11 and 2-27. Not much in the 64 but the 63 manual claims a dynamic balance upon assembly and a final balance when in operation. It shows an image of adding weights  to the Dynaflow torque converter for the final balance.

Section 2-27:  "Completely assembled engines are also given a running test and balanced to very close limits by drilling the flywheel or by adjusting converter balance weights as required".   Also, an underlined Note stating a trimmed torque converter cannot be used with another engine. So remove all weights especially when a previous repair did not mark the orientation on disassembly? Flexplates use weight removal instead of weight addition as on the Dynaflow.

So a test drive is a must with Harmonic Balancer and Flexplate/Torque Converter replacement!

 

John B.

Sometimes fixing a 50 plus year old car....or any machine after original manufacture...deviates somewhat from perfection.

Tom

[telriv]

I've been saying it for a long time now about the factory balance.  No two are alike that's why I ask for pictures of the old balancer BEFORE I send a used replacement balancer so I can compare the pins & drilled holes.

With that said so far there have been no negatives that I'm aware of. They ALL appear to be/run smoothly.

How much of a difference does it really make??? Who knows???  BUT I would imagine it would be in the upper RPM ranges which is probably above what most/many will do anyway.

In stock form I have & do run my 425 "Nail" to 5200-5400 RPM's even when it was new & narry had any problems.

Then again when I rebuilt the engine in the very early 70's & the assembly was balanced & additional drilling was nec. to bring EVERYTHING in balance including the balancer & flexplate.

AND, there's no way the harmonic balancer, or flexplate, can be "Matched" balanced to the originals WITHOUT the assembly, rods, pistons, crank, etc.  You may get close, BUT that's only counts & true in horseshoes.

Just my take on the subject at hand.

 

Tom T.

[RivNut]

Closeness counts in the 3 "H's":  horseshoes, hugs, and hand grenades.  Maybe we could add a 4th - harmonic balancing.

[telriv]

Yeah Ed I was trying to think of the extra add on's & had a senior moment where I couldn't think of anything else.

It's rough gettin' old.

[XframeFX]

So, on the harmonic damper, I noticed Centerville Auto Repair Site recommends center-punching a mark on the hub where the keyway is when it is off the crankshaft. This way it can be compared in relation to the timing mark on the ring when installed.

 

My nailhead idles rough but I attribute it to a missing torque convertor bolt! My 1988 receipt for Dynaflow repair states stripped threads in the 3rd hole. They were fine when I installed it where it failed shortly after and had to be pulled again. Those clowns also broke my turn signal cable man-handling my disabled Riv out of their service bay.

[60FlatTop]

Give me a couple Vee blocks and an electric motor with a pulley that matches your belt size and I'll get you pretty close on the crank assembly.

 

Give me a bigger motor, pull the plugs, and I'll do the whole assembled engine . 1750 or 3500 rpm.

[telriv]

John B,

 

   I think your miss understanding what Russ said.  You put a punch mark on the hub & the outer ring to see IF the outer ring has moved. IF it has the ignition timing can't be set properly.

On the missing converter bolt??? (I remember it to be a nut) should not cause a vibration at idle., IF it was the vibration would get worse as engine speed (RPM's) increased. Read what you mentioned & re-furred to via section 2-27.

 

 

I used to have a wheel balancer that used a strobe light for balancing tires on the car.  I successfully used it to balance a WAY out of balance engines a few times after a re-build.

Made it smooth, BUT I couldn't tell you IF it was balanced properly.

 

Bernie that would be interesting to see & witness being done.

 

Tom T.