Valair flywheel weight

[PLohr]

Just a few points about the Valair flywheel. This is on a 2003 2WD truck with the NV5600.



The Valair flywheel is 5 pounds lighter than the stock flywheel. Stock flywheel is 59. 5 pounds; Valair flywheel is 54. 5 pounds. Valair does not mention this on their website nor did they tell me about the weight difference when I called to ask other questions about their flywheel. I think this difference in weight has caused a slight growl or vibration at 1000 RPM under no load conditions. The truck is drivable - it is not a terrible issue. This same growl/vibration occurred around 700-800 RPM with the OEM flywheel. I think it makes sense - less mass would increase a natural vibration point? Every manual transmission vehicle I have driven has this no load low RPM growl/vibration. I've always assumed it is the first order vibration point of the flywheel/pressure plate/clutch disc assembly (certainly open to other explanations). Everything else in the truck is OEM replacement so the flywheel is the only part that does not have OEM characteristics.



A few other points about the Valair flywheel:

-It does not look to be blanchard ground. There are concentric grooves radiating out from the center.

-The pressure plate bolt holes are drilled all the way through. This puts the bolt holes tangent with the outside diameter of the flywheel. It will likely crack here but the cracks may not be able to migrate into the thicker area of the flywheel. OEM flywheels have blind pressure plate bolt holes and more material at the outer edge.



To the credit of Valair, they did send me a new replacement roller bearing when I called to tell them the bearing that came installed in the flywheel was a little crunchy. No hassle... they just sent it.



I have sent an e-mail message to Valair about the weight difference of the flywheel. No response yet - it has only been a few days though.



I kept the OEM flywheel. It will be resurfaced and machined for the sealed roller pilot bearing and put back in at some point.



Paul Lohr

 

[GCroyle]

I am not affiliated with Valair.



I think there was a change in F/W's that did result in a reduction in the weight. It is noticable on the engine side as filled in vs. a hollowed out rough casting. If you would have looked closely at your Cummins OE F/W it was not ground either. they are machined on a lathe. I just looked at my 2005 OE F/W it was lathe cut and it is the hollow (engine side) casting version. The attached pic is of a 5018079AC. Grinding is the preffered resurfacing technique, it custs thru hardened hot spots better than a lathe can and it is easier to setup and run.



Your comment about the slight growl, you should include information about what type torsion damper you purchased and installed, it makes a difference in noise filtering.



Gary

 

[PLohr]

Thank you for helping me with this, Gary.

I suspected the Valair flywheel had been turned on a lathe. Yes, the OEM flywheel had the same grooves.

I did not know about the change in flywheel weights. Good to know, thank you for sharing this. Do you know what the weight of this 2005 OEM flywheel is?

The torsional damper (aka harmonic damper) is OEM, it has not been changed.

I wonder if a 2005 model OEM damper might reduce the growl?

Paul Lohr

 

[GCroyle]

Paul,



The OE F/W that I personally removed from my '05 NV5600 weighs 49. 3 Lbs.



Sorry, can't offer any input on the damper, a recent hot topic BTW.



In diagnosing, it is very helpful to try to link any insert negative statement HERE with any insert vehicle change(s) HERE.



Gary