Harmonic balancer weight

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1972ho
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Harmonic balancer weight

Post by 1972ho »

I have 2 neutral balance dampners one is a ford Motorsport the other a fluid the fluid one is a lot heavier than the Motorsport and rotating assembly was balanced with the heavier fluid balancer wil it make a difference in power using the lighter Motorsport and will the balance be effected.
mitch
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Re: Harmonic balancer weight

Post by mitch »

if so not enough to notice.I would stay with what it was balanced with.It might free rev quicker
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Re: Harmonic balancer weight

Post by geraldtson »

If it were a diesel i'd consider the Fluid Damper if not i wouldn't use it. If the damper's are both neutral then you can use either one.
statsystems
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Re: Harmonic balancer weight

Post by statsystems »

Use the Fluidamper.
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Baprace
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Re: Harmonic balancer weight

Post by Baprace »

1972ho wrote: Fri Nov 17, 2017 3:42 pm I have 2 neutral balance dampners one is a ford Motorsport the other a fluid the fluid one is a lot heavier than the Motorsport and rotating assembly was balanced with the heavier fluid balancer wil it make a difference in power using the lighter Motorsport and will the balance be effected.
It's my understanding you cannot balance a crankshaft with a fluid balancer, I would use the Ford motorsports balancer.

geraldtson has it correct.

From the fluiddampener web site ;

Why can't Fluidampr or Streetdampr be spun on a balance machine?
Balancing a crankshaft with the Fluidampr or Streetdampr is not recommended. The Fluidampr (or its damper ring) and the Streetdampr contain an inertia ring that can rotate inside. This inertia ring is balanced to very close tolerance specifications at the factory but may not be to perfect “zero” balance. When the damper is spun on a balance machine, this inertia ring may rotate inside the damper and the operator may be chasing this small imbalance while attempting to balance the crankshaft. When the damper is installed and running on a combustion engine, the shear forces on the silicone fluid inside the damper from the torsional moments of the engine crankshaft, centers the inertia ring on its bearings. A balance machine does not generate torsional shear forces and the inertia ring may not be completely centered in its bearing clearance gaps. (IT WILL BE CENTERED AND IN BALANCE WHILE RUNNING ON AN ENGINE ) Note: Our new CT Gold Dampers do allow the crankshaft to be balanced while the damper is installed.
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Re: Harmonic balancer weight

Post by Mark O'Neal »

statsystems wrote: Fri Nov 17, 2017 7:07 pm Use the Fluidamper.

If your shop door won't stay open.
jsgarage
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Re: Harmonic balancer weight

Post by jsgarage »

Ford has many elastomeric balancers. Generally, the lower the engine performance, the lighter the balancer. Boss 302s and Boss 351s used 12+ lb assemblies while trucks got 8-9 lbs. Most if not all are pressed together frozen, not glued so age debonds (such as it is) the inner & outer ring as the rubber shrinks. You gradually lose the timing marks & sometimes, the outer ring flies off or moves inward & saws a hole in the timing chain cover. Nothing like a Romac!
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Re: Harmonic balancer weight

Post by statsystems »

Mark O'Neal wrote: Sat Nov 18, 2017 1:47 am
statsystems wrote: Fri Nov 17, 2017 7:07 pm Use the Fluidamper.

If your shop door won't stay open.

I've used at least a hundred of them with never a failure.
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Re: Harmonic balancer weight

Post by MadBill »

The implication from that Fluidampr note is that if you're using their non-CT Gold damper, you should balance the assembly without the damper and trust that it is accurately zero-balanced by the factory. On the other hand, if it was spun with the Fluidmpr and gave the machinist no problems with shifting numbers, then it should be OK.
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Re: Harmonic balancer weight

Post by sanfordandson »

Mark O'Neal wrote: Sat Nov 18, 2017 1:47 am
statsystems wrote: Fri Nov 17, 2017 7:07 pm Use the Fluidamper.

If your shop door won't stay open.
Agree!
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Re: Harmonic balancer weight

Post by engineguyBill »

The actual weight of the balancer is not necessarily critical, as long as it is within reason. The diameter of the balancer is more important however, in a high RPM application. Maximum-effort high RPM race engine will want/need smaller diameter (i.e. 6 inch) balancer. For street application, balancer weight/diameter are not critical, as long as the balancer is balanced correctly for the application.
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1972ho
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Re: Harmonic balancer weight

Post by 1972ho »

I guess I had better call the machine shop to see what there thinking is,I know they had to remove a lot of weight from the counterweights to balance it but that was mostly due to lighter weight parts that are used this time on the crank.
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Re: Harmonic balancer weight

Post by statsystems »

engineguyBill wrote: Sun Nov 19, 2017 10:09 am The actual weight of the balancer is not necessarily critical, as long as it is within reason. The diameter of the balancer is more important however, in a high RPM application. Maximum-effort high RPM race engine will want/need smaller diameter (i.e. 6 inch) balancer. For street application, balancer weight/diameter are not critical, as long as the balancer is balanced correctly for the application.

All very true.
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Re: Harmonic balancer weight

Post by pamotorman »

in NASCAR when they first tried fluid dampers they had trouble with the front snout of the cranks breaking off till they went to BBC sized snouts on the SBC cranks.
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Re: Harmonic balancer weight

Post by statsystems »

pamotorman wrote: Sun Nov 19, 2017 5:31 pm in NASCAR when they first tried fluid dampers they had trouble with the front snout of the cranks breaking off till they went to BBC sized snouts on the SBC cranks.

I've seen those. Most of the time the dampener didn't fit the crank
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