Solid harmonic balancer?

[RF_Burns]

Hi all,
Shortly after getting my coach, about 10 years ago... it was determined that the timing chain needed to be replaced. I got the parts from Mondello's.
The front seal was also leaking so I got a new harmonic balancer from them as well in case the seal area was leaking.

Everything was installed by my local fleet garage.

I noticed that the new harmonic balancer didn't have a rubber isolating ring in it like the old one. It appeared to be just a piece of solid metal. I
believe it was this 8080 model:

https://mondelloperformance.com/product-category/cranks-rods-accessories/harmonic-balancers-cranks/

My engine always seemed to run rough (vibrate), its not smooth as I rev it up and seems to have resonant rpm's where the vibration is more pronounced.
The engine was rebuilt by Dick P and was not smooth after that either. I didn't drive it much before the timing chain replacement to remember if it
was smoother then. It had a Holley carb which was running rich as well (EFI since 2010 now)

So my question is, is this "harmonic balancer" from Mondello really just a piece of solid metal and meant for race engines not normal applications?
And could it be the cause of my engine vibrations and roughness? or does it have some voodoo magic inside it that does not require the use of the
rubber isolation ring.

The light came ON in my mine today as I was under the coach and noticed the "solid" harmonic balancer.

I came across a good writeup on the purpose of the harmonic balancer here:

http://www.mkivsupra.net/vbb/showthread.php?35945-Crankshaft-Pulley-Damper

Thanks
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[chris tyler]

I believe that is a "Fluidampper" type that uses elestametric viscus fluid inside. The housings ar laser welded and at first apear one piece.
I have used them for years on other engines

--
76 Glenbrook

 

[CGeils]

Crank pulleys willl have a balance weight on some applications (including Olds), but the reason for the rubber damped ring is not for rotating or
reciprocating balance. The rubber damper portion is to partially cancel torsional vibrations, that is, twisting of the crankshaft front to back. Yes
that big stout piece of iron can twist at 5000 rpm, and the rubber isolated portion of the balancer helps cancel some of that. A periodic vibration
at lower speeds is typically due to a rotational or reciprocating imbalance. If your engine has ever been rebuilt and had at least one piston changed
this might be the cause of what your are feeling. The piston mass(es), if different than OE, would cause a reciprocating imbalance that could be felt
at moderate speeds. The Mondello solid balancer could also cause an imbalance if the bobweight portion of the balancer has a slightly different mass
than OE. I don't think the solid balancer would cause any change in feel at moderate speeds, like 2-3000 rpm, where we normally run.
--
Chris Geils - Twin Cities / W Wa
1978 26' Kingsley w/ very few mods; Headers, PD9040, aux trans cooler, one repaint in stock colors, R134a, Al rad, Alcoas, 53k mi

 

[RF_Burns]

Thanks guys,
I pulls from a stop and driving smooth, just revving up from idle there is a roughness or vibration. Seems to have a resonance about 17-1800 rpm.

So maybe I'm just looking for something that is not there. I'm sure Dick would have said something if he noticed a vibration when he was breaking it
in after the rebuild.


--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that