Fluid dampr or harmonic balancer

[WCantrell]

So, it is time to replace my old balancer. I've heard that there are fan clearance problems with the fluid damprs. I've also heard that there's a spacer ring for fan nut. Opinions?

 

[WalterJ]

Hey WCantrell;

I needed new gaskets on both my front covers, so time to bite the bullet & replace oil pump & vib damper. The engine vibration @ 2000rpm was noticeable & ignored too long.

Much talk in TDR about using Fluid Power viscous damper to replace OEM, but it would necessitate removal to change serpentine belt--arrrgh.

I therefore decided on the ATI damper #917374 option, as it specs a smaller 7.8" O.D., than OEM, [about same price] thus facilitating easier serpentine belt changeouts. This 3-piece design ATI is also "rebuildable" by replacing its internal O-Rings, a totally unique design rated for damping 800+HP engines for 10 years.

My improvement @ 2000rpm is noticeable.

 

[HHhuntitall]

I'm unaware of any fan clearance issues.... I've mounted several Fluid dampers on modified 12v engines, and never had a problem, unless we lost a piston or valve.... They're high, but any tuned or uprated engine generates more crank harmonics than the factory damper can handle, so the aftermarket dampers are the ticket to keep your front seal and vibration down.

 

[MMeier]

Hey WCantrell;

I needed new gaskets on both my front covers, so time to bite the bullet & replace oil pump & vib damper. The engine vibration @ 2000rpm was noticeable & ignored too long.

Much talk in TDR about using Fluid Power viscous damper to replace OEM, but it would necessitate removal to change serpentine belt--arrrgh.

I therefore decided on the ATI damper #917374 option, as it specs a smaller 7.8" O.D., than OEM, [about same price] thus facilitating easier serpentine belt changeouts. This 3-piece design ATI is also "rebuildable" by replacing its internal O-Rings, a totally unique design rated for damping 800+HP engines for 10 years.

My improvement @ 2000rpm is noticeable.

Thought the 917374 was only for the early HPCR engines , not a first gen rig ? Have one for my 03 , or will sell.

 

[JDancoe]

My brother & I both installed a Fluiddampr on our 1st Gen. CTD's. We did have fan clearance problems. I found a couple of hardened washers about 1/8" thick which ALMOST fit inside the fan nut. I ground them down to slip inside the fan nut and that gave us enough clearance.
We also had an issue with one of the speed sensors that amounts near the damper. FluidDampr did provide a modified bracket, but one truck had an old O.E.M. sensor. We purchased a new sensor from Geno's Garage-Cummins P/N 3924432-
At that time this sensor was listed as a part for 2nd Gen. trucks, but I notified them and they revised their catalog description.
The difference is that the new sensor has (2) slotted mounting holes for adjustment, rather than just one like the original. This makes the adjustment of the sensor much easier.
Yeah, you have to move and then re-adjust the sensor when changing the serpentine belt, but how often do you have to change the belt? I do mine every 100K (wether it needs it or not).

Hope this helps,
Jack Dancoe

 

[HHhuntitall]

That's weird, Jack.... What year trucks did you guys have? I put one on my '93, and it fit fine, aside from the sensor relocation.... I've installed several others, and with factory fans, I don't recall there being an issue for clearance....

 

[JDancoe]

They were both 1992 with the stock engines, stock fans. They both would just "Tick" the blades against the balancer with the belt off and spinning the fan by hand. The 1/8" spacer provided plenty of clearance, and we've had no problems since, with either truck.
Jack Dancoe

 

[HHhuntitall]

Now I'm curious..... when did ya'll do that? I'm wondering if there's an updated dampener.....

 

[JDancoe]

They were done in October, 2011.
Jack

 

[HHhuntitall]

So, in deep consideration of this matter, I've been staring at the underside of my '93 for about 10 minutes... where could the difference be? (yes, I know, I'm borderline OCD... but only when I have the energy) Then, as I'm thinking of turning bearings and spinning the fan by hand, it hits me... the pressed in bearing in the fan pedestal! That can be installed at different depths. Perhaps that's where the issue lies? I've got 1/4" of clearance in mine, so I'm guessing the bearing is not pressed in as far as yours is.... And having installed some new bearings on second gen's, and noticed that they are further from the dampener than they were before, it would make sense that that would be where the difference would come from... Both the fan center shaft and bearing are pressed in, so there could easily be 1/8" on each in either direction, I would think. Eyeballing the belt doesn't appear to reveal any belt misalignment, but now I'll be checking it with a straight edge when she goes in for service....

 

[JDancoe]

HH,
You may be on to something there!
Neither mine nor my brothers trucks seem to have any belt alignment problems. As I said in my earlier post I change belts about every 100K. Not seeing any wear, just doing it out of guilt, I guess. We are both still running the original fan pulley bearings, I check mine when I change the belt, or any other time I have occasion to loosen the tensioner or remove the belt for other work.
(Alternator repair, water pump, front seal, etc. I don't hear any noise, or feel any roughness or wobble. (330,000 Miles).

 

[DMcLeod]

I put a fluidampr on my 92 a couple years ago. It did not fit out of the box. Fan blades hit the damper, sensor bracket did not fit, etc. I talked with manufacturer, but not sure if they did anything about it. I let Genos know as well. Read this thread:https://www.turbodieselregister.com/threads/244658-Fluidampr-for-1st-Gen
I'm happy with the product, but not the installation.

 

[WCantrell]

Fluid dampr installed, and here is what I found.

I did have to shim the fan.

On the first install the fan barely cleared the damper, so I added a 1/8 washer under the hub nut. Under high rpm the fan would graze the damper, so I installed a second washer. All seems to be good now.
-The fan was the upgraded 52028653.
-The pulleys were well aligned already (I had access to a Dayco Laser/magnetic alignment tool).

I choose to modify the sensor bracket (per install instructions) instead of buying the updated sensor.

As for the value of the fluid dampr, well worth the install.

Thanks for everyone's input.

 

[DMcLeod]

Under high rpm the fan would graze the damper

Interesting, I figured the higher the rpm, the more the fan would flex forward, giving more clearance, not less.

 

[WCantrell]

Interesting, I figured the higher the rpm, the more the fan would flex forward, giving more clearance, not less.

Me too. All I can think of is the fan has more airflow across the top since the dampr takes up a good deal of real estate behind the lower part of the fan. Maybe the fan is able to bite more air at the top causing it to lean forward under rpm. Who knows...