Harmonic Balancer, what's the deal?

[XframeFX]

I did understand about the center punch marks, just didn't put it to words correctly.

 

That Torque Converter Bolt. I took it as a Bolt but the 1988 receipt simply says "Stripped Threads". Been a long time, so it's missing a Nut. Not fixing it because I'm itching to do that ST400 swap if I ever get all my other issues resolved on this project.

 

I like your Strobe Light Balance Method Tom. I have a feeling I'll need to address this at some point in time (after the ST400 swap). That 'thumping' inside is more like a mis-fire. I hardly run it and 0 miles in 25 years. Not liking the way it runs but another thread if I encounter a dead-end.

 

John B.

[RockinRiviDad]

On 3/29/2019 at 8:59 AM, petelempert said:

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

Let’s not turn this into a driveline topic. But I am chasing a vibration like a few others on this forum. I’ve tried ALL the normal stuff with no luck. This thread has me thinking it might be my balancer???
 

I bought a replacement harmonic balancer from Larry Daisey years ago. I don’t think the balancer I replaced was original to my car either. 

So, how do guys like me get the engine balanced with the replacement harmonic balancer??? 

[telriv]

The ONLY RIGHT WAY TO DO IT is when the engine is being rebuilt as it's ALL balanced from the factory as a COMPLETE unit. Crank, rods, pistons, flywheel/flexplate, harmonic balancer.  ALSO taken into consideration is the approx. weight of nec.oil/lubricate, rod bearings, etc.

So as you can see there is ONLY one way to do it right.

Not to say one could luck out & hit upon something that makes it better, BUT the unknown, is it RIGHT???

Anything other than that is hit & miss.

 

Tom T.

[RivNut]

It's not a nailhead put you'll get the idea

 

[RockinRiviDad]

Cool pic Ed. I’m assuming u posted that for illustration purposes. Because I don’t see pistons, rods & all the other stuff Tom mentioned. 
 

Do machine shops actually do the balancing when they put the engine together? Or would I have to ask. I would think that a machine shop would done it knowing it’s an externally balanced engine

[Bloo]

Pistons and rods (rods at each end) are made to match close to perfectly in weight. What happens to the crank depends on what the engine is.

 

On a v8, "bobweights" are calculated from the now known piston and rod weights, and attached to the crank. Then the crank is spin balanced with the bobweights on it. Externally balanced engines must have any special balanced parts (balancer and or flywheel) attached to the crank while it is spin balanced. The setup is going to look just like RivNut's picture.

 

Balancing wouldn't be done by a machine shop unless you request it. Highly recommended IMHO.

 

Edited June 4, 2020 by Bloo (see edit history)

[RivNut]

You have to use the bob weights because rods w/ pistons would just fling around when spinning.  One thing that's not mentioned is that because the rods and pistons are not attached to the crank when it's being balanced, you need to weigh each piston, rod w/ cap and bolts, piston pin, and you're really serious, the piston rings.  Find the lightest of each and take material from the others until every piece weighs the same, like within 1/4 of a gram.  

 

While you're at it, you might as well match the ports on both the intake and exhaust.  In order to port match, material must be removed. As long as your removing material you might as well polish those surfaces. 

 

By the time you've gone through all this, you'll have made at least the first two payments on that second mortgage you took out to pay for all of it. 😕

[KongaMan]

Or you could just bolt it back together, on the likelihood that it will still last the rest of your life.  

[RivNut]

[Roadmaster75]

There is a small paragraph in the 1973 Buick shop manual for 455 

equipped cars that calls out “clip on flex plate weights” .

These were specified to help solve customer complaints of vibration or roughness

NOT attributed to belts, pulleys, accessories, etc.

Weights were to be clipped on the flex plate in various locations until

the roughness was eliminated or minimized.  
Perhaps a similar procedure existed for later model nailhead cars.....?

 

I’ll try to find the paragraph today........

 

[Turbinator]

On 6/4/2020 at 6:35 PM, telriv said:

The ONLY RIGHT WAY TO DO IT is when the engine is being rebuilt as it's ALL balanced from the factory as a COMPLETE unit. Crank, rods, pistons, flywheel/flexplate, harmonic balancer.  ALSO taken into consideration is the approx. weight of nec.oil/lubricate, rod bearings, etc.

So as you can see there is ONLY one way to do it right.

Not to say one could luck out & hit upon something that makes it better, BUT the unknown, is it RIGHT???

Anything other than that is hit & miss.

 

Tom T.

Tom, ever heard a hit and miss engine run?

The hit and miss engines were popular on farms. The farms had no electricity so they used hit and miss engines. I’ve seen hit and miss engines power a MayTag washing machine. Something was balanced as the engine and May Tag just chugged along..

[telriv]

Oh yes Bob. Not only have I seen MANY I helped a guy get his up & running again when I was at a show.

It would run ALL day on about a quart of gasoline. It's astonishing watching how the vales are actuated, how the rod was oiled along with the cylinder wall & piston. 

Amazing technology for the time.   Even today.

 

Tom T.

[65RivProject]

I replaced belts on my 65 project and noticed the crank balancer was loose.  The nut was only at about 60 ft-lbs, so tightened it down to 100 and it still flopped around. I know, 200+ is correct torque, but I decided to pull it and take a look.  The ID is at 1.440 and crank OD is 1.426, but the big news is, the balancer is cracked.  Since I'd like to stay with the original unit, is there a way to fix this, or is it junk?  And is 1.426 in spec for the crankshaft OD?

Edited May 2, 2023 by 65RivProject
add'l images (see edit history)

[Seafoam65]

The balancer is junk.......your crank is fine......get   another balancer and torque it properly.

The balancer cracked because it wasn't torqued properly.

[65RivProject]

Thanks!  I was thinking of having a machine shop rebuild it.  I've worked on a lot of cars, many years ago, and just recently started getting back into it.  This is my first Riviera - love that style!  She's not in good shape, but I'm bringing her back from the brink.  Would you know where I might find a used balancer for the 401?  Thanks again!

[NC1968Riviera]

8 hours ago, 65RivProject said:

Thanks!  I was thinking of having a machine shop rebuild it.  I've worked on a lot of cars, many years ago, and just recently started getting back into it.  This is my first Riviera - love that style!  She's not in good shape, but I'm bringing her back from the brink.  Would you know where I might find a used balancer for the 401?  Thanks again!

Contact Gene @abandg in Pennsylvania. He sells first Gen Riv parts and may have what you need.

[arnulfo de l.a.]

Are these not balanced to the engines they are mounted to at the factory? How would one from another engine affect your engine? I would try fixing yours if possible. A good machine shop can weld that and machine the od and id to spec.good luck.

[SparkKeeper]

I don't mean to highjack the thread but I am hoping for some guidance on the harmonic balancer woes as well. My '65 Riviera with a 401 had a wobble in the harmonic balancer due to a loose crank bolt. I pulled the balancer and had it rebuilt by Damper Dudes in Anderson CA, I torqued the balancer to 225 lbs and still see a wobble. The harmonic balancer appeared to be in good shape and had no visible cracks. The before pics (blue) and after pics (black) show no major damage to my untrained eye, However it was noted that my 3 groove crank pulley is bent. 

 

I am uploading a few youtube videos of the engine running with the balancer installed and fully torqued down to show the wobble and ask your opinion if this acceptable or problematic. Thank you

 

 

[avgwarhawk]

The pullies appear to be bent.  The balancer appears to be true.   

[OldGerman]

23 minutes ago, avgwarhawk said:

The pullies appear to be bent.  The balancer appears to be true.   

I would disagree. In Slow Motion you See the whole thing wobbel. 

Something is wrong. 

[avgwarhawk]

42 minutes ago, OldGerman said:

I would disagree. In Slow Motion you See the whole thing wobbel. 

Something is wrong. 

Possible.  I would run it on the lathe again.  Remove the pullies.  Use a straight edge on the flat surface.    

[arnulfo de l.a.]

The outer most pulley does not appear to be true. But also ,looking closely at the surface of the balancer snout that mkes contact with the crankshaft when torqued down, it looks to me that the balancer may not be seating against the crankshaft for entire 360 circumference. With the the key positioned at 6 oclock, look at the mating surface of the balancer between 10 oclock and 12 oclock. To me it looks like there was just enough of a gap in that area to allow oil to seep in verses the rest of the circumference.

[RivNut]

Contact Russ or Matt Martin for information on the different years/styles of balancer. For their contact info Google “Russ Martin Nailhead”. He’s from Centerville, CA. A real nailhead guru.

[XframeFX]

1 hour ago, RivNut said:

Contact Russ or Matt Martin for information on the different years/styles of balancer

Agree. Check with them on external balance requirements for specific Nailheads and if it is a concern.

 

I'd say anything other than an original Harmonic Balancer would get you "In-the-Ball-Park" for balance of rotating/reciprocating mass. Infact, external balance masses are considered "a trim balance". An excessive imbalance has to be corrected on the Crankshaft assuming all reciprocating masses are correct.

 

Excellent Images and video Sparkkeeper. Certainly helps trouble shooting.

Rivnut's June 4th, 2020 image of an assembly with bob weights on a balancing stand is the correct procedure PRIOR TO FINAL ENGINE ASSEMBLY of course. Definitely worth the expense.

 

However, back to the Balancer, There were many final year Nailheads (1965-66) at DVP Auto's Black Canyon Lot in January. A last resort if you can't find any.

 

 

 

 

 

 

 

Edited May 4, 2023 by XframeFX (see edit history)

[RivNut]

7 hours ago, OldGerman said:

I would disagree. In Slow Motion you See the whole thing wobbel. 

Something is wrong. 

Find a spot on the front cover and watch the balancer. It does not run in a true circle.

[65RivProject]

DVAP recently moved much of their stock, including all Rivs, from the Deer Valley (Black Canyon) location to Casa Grande. Unfortunately, they do not have any 1st gen Riv balancers.

"As of now the pre 656' inventory along with ALL AMC, ALL IHC, ALL CORVAIR, ECONONLINE, ALL TORONADO, ALL RIVIERA's ALL GM "G" BODIES, GM BIG BODY 77 and up, are at our south location, Casa Grande. ...contact them direct toll free 800-798-2465"

Edited May 10, 2023 by 65RivProject (see edit history)