While at the GTG I checked the damper on my 5.9L Cummins and found it to be wobbling AGAIN! The design of this damper is VERY POOR as the serpentine belt pulley is part of the damper and the power for the belt goes through the rubber isolator.

Why am I going through these things? Well the mileage for one and I am driving a much bigger fan and alternator than most. The rubber isolator will not stand up to the load. Further, I have to have the tensioner a bit tighter because of the alternator load or the belt squeals like a stuck hog when the batteries have been used.

Will be getting a fluid damper which has an internal damping ring isolated by a silicone fluid and the pulley is directly attached so no more rubber isolator to deteriorate!

I am having a custom pulley built to add a second alternator. I will move the 200 amp alternator to this pulley and then replace the 200 amp alternator with a 160 amp. The 200 amp will charge the house batteries with a 3 stage regulator and the 160 amp will charge the chassis batteries. I will still have a Big Boy contacter to parallel house and chassis batteries if necessary.

More to follow as I get the parts and pieces!

Our Breakaway has mounting brackets for an alternator or something that was mounted under the engine. No documents to explain them.

I installed a Fluidampr in Dec '13...the crankshaft pulley on mine is also dampened - one of the things the shop in KY replaced.

quote:

Originally posted by Gary Carter:
Our Breakaway has mounting brackets for an alternator or something that was mounted under the engine. No documents to explain them.

I saw that when I visited you a couple of years ago. I was interested because I didn't see a pulley, I will have a clearance problem with the fan shroud but it should be a small problem. Finding a place for the alternator may be a much bigger issue.

quote:

Originally posted by Rusty:
I installed a Fluidampr in Dec '13...the crankshaft pulley on mine is also dampened - one of the things the shop in KY replaced.

Sounds like the tensioner was the root cause of your problem, right? On your fluid damper is the pulley isolated by rubber or is it a solid piece?

The Fluidampr is for the crankshaft. The "damper pulley" drives the serpentine belt. We speculated that the hammering the defective damper pulley imposed had worn the pivot shaft on the old tensioner and allowed the tensioner pulley to tilt slightly. When it was dry, friction held the belt engaged, but when it became slippery from water, it slipped off.

Of the three times it threw the belt, all were after running through standing water, and twice the belt was completely undamaged, excluding the possibility of a locked shaft on one of the the driven accessories.

The new parts got a test on the run from Goshen to Traverse City; I had a couple of hours of rain, of which a third was very heavy. Lots of ponding. 1009 miles after the repairs, there's been no hint of a problem.

quote:

Originally posted by Rusty:
The Fluidampr is for the crankshaft. The "damper pulley" drives the serpentine belt. We speculated that the hammering the defective damper pulley imposed had worn the pivot shaft on the old tensioner and allowed the tensioner pulley to tilt slightly.

Not quite sure what you mean by "hammering" of the defective damper pulley? Is the pulley rubber mounted to the damper therefore the pulley could become detached or wobble on the damper? If the damper and pulley are one solid piece, I don't understand how there wold be a hammering effect unless the internals of the damper failed. In that case I would think you would have had a crank snout failure. Fluid dampers are warranted for life.

The damper pulley could rock back and forth (in fact, it damaged its mounting bolts' heads so they couldn't be reused).

The design is such that the pulley can't wobble; the rubber inserts act as snubbers, but they bear none of the radial load. The inner section (attached by four bolts to the crankshaft damper) serves as the hub for the outer section with the belt pulley itself. If the rubber has deteriorated, the sections can rock back and forth.

My '91 diesel Nissan Maxima had a damper like yours, which would wobble when the the rubber was shot.

BTW, Fluidampr is very responsive to email queries about which one for the engine. I think yours is this one.

With all the other things I have going on, I finally got around to putting the fluid damper on the 5.9L Cummins yesterday. The fluid damper is a bit thicker than the OEM unit so I had to cut a little off the fan shroud at the lower end. Will not be a problem as the fan is inside the shroud a little ways. I could not quite get the new unit over the end of the crank with out the shroud relief.

The old damper was not as bad as I thought but probably in the early stages of failure. A slight wobble but the timing marks still were within tolerances.

There was a BIG difference in the idle smoothness of the engine with the fluid damper. The engine always had a bit of a shake at idle but that is completely gone now. This was confirmed by measurement with an accelerometer comparing before and after reading. Above 1500 RPM not much difference.

I am back to the drawing board about the second alternator. I don't think there will be enough room for an additional serpentine pulley to be added on the fluid damper and clear the fan.

By changing the existing alternator to a larger unit,back to the 200 amp three stage regulator for house batteries and going to a much smaller unit for the chassis batteries like a 100 amp I should be able to use a single "V" belt which I could fit in.

I could always cut in the big alternator for quick charge of the chassis batteries and really don't need much maintenance charging while driving even with all the driving lights and accessories on.

More thinking!

Hope everyone had a safe and happy 4th!

Ed,
Where did you get the Fluid Damper? The Cummins OEM damper inspection is on the maintenance schedule and they do fail! Ours said goodbye New Years Day a few of years ago when leaving a campground in Nashville. It is showing signs of wobble again.
Thanks
Billy T

I got mine at Summit Racing, but I don't think they carry dampers for larger engines.

http://comfleet.com/pages/Diesel/Pitts/Balancers.html
Anybody ever try one of these?

Buried in the verbiage is a recommendation to use it with a fluid damper...

Billy, I called Fluid Damper and they gave me a phone number of a stocking distributor, I think it was Summit, but IIRC it came from Ohio. I am in Texas now and don't have access to my purchase records. I will check with home to see if wifey can find.

Billy, Fluid damper does not make one specifically for the Cummins 8.3L but ATI does!

ATI for 8.3L

I suggest that you call them and get their stocking locations.

Ed,
The ATI is for the ISC. I have requested info whether it is backwards compatible to the C8.3TA. Thanks for the heads up!
Billy T