Timken Clutch Release bearing, NV5600

[GCroyle]

See the hot spot?

Last spot to leave the disc and first spot to make contact. Mirrors position on flywheel.

Causes chatter on clutch engagement.

Can you inspect all 4 sets of drive straps and look for uniform profiles in all straps. Bends should be identical.

I’m sticking with my earlier theory for noise.

 

[Darkbloodmon]

See the hot spot?

Last spot to leave the disc and first spot to make contact. Mirrors position on flywheel.

Causes chatter on clutch engagement.

Can you inspect all 4 sets of drive straps and look for uniform profiles in all straps. Bends should be identical.

I’m sticking with my earlier theory for noise.

Oh I see the hot spots alright. I could feel the chatter to, letting it out.

I'll get pictures of the straps. Can the flywheel get resurfaced or does it need to be replaced?

 

[Tuesdak]

What did the old clutch and flywheel look like? Why are they being replaced again: power upgrade or problems? As in is this a new problem or an old problem that's ruining clutches?

Do you have or can you rent a magnetic dial indicator? I would put it on just on the outside of friction band of the flywheel and spin the engine over slowly by hand. With the bolt hole problems maybe the flywheel didn't get on the crankshaft straight. Same with the input shaft of the trans: make sure it isn't bent.

Do you want to pull the trans after a resurfaced flywheel comes back to haunt you with those "cementite" hot spots? IMO it's ruined garbage. Just unreal that the hot spot is only in one area. (It's possible Kevlar just leaves a black mark without cementite temperatures, but, it's still a big problem. Good question to be asked.)

Cementite is iron carbide formed by excessive heat and will be thicker in the area. So the formation of cementite expands to becomes a high spot and the high spot gets hotter and forms more and deeper cementite. If the flywheel grinding misses any of it ... it comes back quick and is nothing but trouble. Note: Common for the undersized brake systems, due to CAFE, to get hot spots like this that turning doesn't fix. The "carbide" turning tool, yeah same material, bounces off cementite and leaves them alone as high spots thus why grinding is the only hope. Myself I simply toss brake rotors and flywheels because it's too much of an expense or PIA to mess with it again in 3000 miles when cementite comes back.

 

[GCroyle]

We had a casting engineer from Webb Wheel a sister company to us look at same but worse looking Cummins application flywheel and said it was Martensite and actually wrote a descriptive document of what causes it and it’s ugly deeper side. We later published a bulletin about it for training purposes.

Facings were bystanders this time.

Is it possible it’s a bad cut on the flywheel possible but less likely IMHO than a damaged drive strap allowing that side to drag. But comments are based only on latest pics.

This video was based on hot spot discussions we had.

Gary

 

[Darkbloodmon]

What did the old clutch and flywheel look like? Why are they being replaced again: power upgrade or problems? As in is this a new problem or an old problem that's ruining clutches?

Do you have or can you rent a magnetic dial indicator? I would put it on just on the outside of friction band of the flywheel and spin the engine over slowly by hand. With the bolt hole problems maybe the flywheel didn't get on the crankshaft straight. Same with the input shaft of the trans: make sure it isn't bent.

Do you want to pull the trans after a resurfaced flywheel comes back to haunt you with those "cementite" hot spots? IMO it's ruined garbage. Just unreal that the hot spot is only in one area. (It's possible Kevlar just leaves a black mark without cementite temperatures, but, it's still a big problem. Good question to be asked.)

Cementite is iron carbide formed by excessive heat and will be thicker in the area. So the formation of cementite expands to becomes a high spot and the high spot gets hotter and forms more and deeper cementite. If the flywheel grinding misses any of it ... it comes back quick and is nothing but trouble. Note: Common for the undersized brake systems, due to CAFE, to get hot spots like this that turning doesn't fix. The "carbide" turning tool, yeah same material, bounces off cementite and leaves them alone as high spots thus why grinding is the only hope. Myself I simply toss brake rotors and flywheels because it's too much of an expense or PIA to mess with it again in 3000 miles when cementite comes back.

I'll have to get pictures, they didn't look trashed as this flywheel. This was a standard clutch job on a untuned truck. New clutch going in has higher holding capacities and was more durable over the long term in preparation for tuning down the road. Previous clutch had no problems besides age and symptoms of a noisy throw out bearing, there was considerable wear on the fork and ball stud and grease the contact points was sparse.

I'll get a dial indicator on the flywheel later, it went on alright, torqued to 101ft/lbs. All the bolts were marked directionally so they could be observed if they move. Orange thread locker used on all the flywheel bolts.

No, I don't want to pull this trans again for a flywheel. So I've now got a 350.00 disc of steel with less than 2 miles on it and its toast. SouthBend has a tight warranty window and that has long passed the 90 day mark when I bought this flywheel in preparation for this clutch job over a year ago. Funny how wood has better prices than steel now.

I'll start getting a list of questions together for Phoenix Friction today. Keep them coming please, i'm out of my element on this.

 

[Darkbloodmon]

Can you inspect all 4 sets of drive straps and look for uniform profiles in all straps. Bends should be identical.

Here are the pictures of the drive straps and pressure plate.

 

[Darkbloodmon]

 

[GCroyle]

DBM ,

Sorry I can't review the pics of the straps as presented. They are all different orientations, angles etc. This is a pic of a spare I have, four pics on of each strap set with the same exact presentation and I might be able to see and comment on the straps. Mark each pic with position 1, 2, 3, 4 so you can see match to your clutch. The more consistent the image presentation the better.

The straps pull the casting in rotation from the cover that is bolted to the FW. All of the engines rotation power goes thru the straps.

The next function of these straps is to pull the casting AWAY from the FW and create a uniform gap allowing the disc to spin freely not touching the castings. This plate lift is only about .040" - .045" so uniformity of plate lift has a significant impact on release and smooth engagement.

Gary

 

[Darkbloodmon]

The more consistent the image presentation the better.

Are these better? Hot spot is between 1 and 4, closer to 4.

 

[GCroyle]

DBM,

Much better. The first thing I looked for was if a set(s) didn't have the same profile as the others. Really didn't see it. Then I tried to look for anything that is not like the others. At the pressure plate casting to straps you see rivets, all uniform but at the strap to cover it's a bolt and nut, not riveted. That indicates a modification involving separating the casting from the cover. Moving on, now look at the OD of the washer between the bolt and strap. Are they all the same? By eye and you need to confirm this are they the same OD? If not then w/o testing the plate lift by measuring it exactly does the washer OD variation affect the point at which the strap is bending from for release? Or are the washers just in different positions and making it look shifted.

I can't tell, it's a long shot hunch. If you have calipers measure the OD of the washer w/o disassembling.

When these are made, the plate to strap rivet and strap to cover rivet are two different rivet sizes of course but the OD of the head of each part number is identical.

Another thing that can be observed but only when bolted to a FW with the disc is the height of each diaphragm spring tip and then the runout of them to each other. The more uniform the better. Some variation is almost inevitable but the flatter the better.

Gary

 

[Darkbloodmon]

If you have calipers measure the OD of the washer w/o disassembling.

All washers are centered and measure 20mm.

 

[Darkbloodmon]

Do you have or can you rent a magnetic dial indicator? I would put it on just on the outside of friction band of the flywheel and spin the engine over slowly by hand.

Just measured the run out on the flywheel, not more than .03 of an inch

Here is a picture of the old one. Called SouthBend for the runout specs on the flywheel awaiting a call back. Emailed Phoenix Friction about the clutch and gave them a call, waiting on a follow up with the gent I spoke to originally.

 

[Darkbloodmon]

Just off the phone with Phoenix Friction here are the notes from the call paraphrased

"Hot spot is apart of the break in procedure, the high spots on the surface are hitting and will wear away after the 1000mi brake in on the clutch"

"The wear and contact pattern on the disc are a concern, and warpage may be a factor"

"The noise is gear roll over from going from a dual mass to single mass" I had to inform him that this is an NV5600 and both flywheels (Old and New) are single mass. I mentioned that I've never had gear rollover noise like this on the OEM clutch.

At this point he offered to send out an RMA request for the whole clutch kit so that they could look it over. I asked if he wanted the flywheel to inspect as well and he said no it's not ours. I'm considering sending the flywheel out to SouthBend to get a second opinion on it since Phoenix doesn't want to touch it. If the hot spot is normal for this clutch maybe SouthBend could confirm this from their own inspection.

 

[GCroyle]

OK getting a bit ugly here and I'm just involved cause I take pride in the industry I retired from and proud that some of my cohorts called me a Clutch Guy.

OOPS hit expand to see my ramblings.

Oh I see the hot spots alright. I could feel the chatter to, letting it out.

"Hot spot is apart of the break in procedure, the high spots on the surface are hitting and will wear away after the 1000mi brake in on the clutch"

I'm throwing a BS flag on the field for this one. That concentrated dark blue is screaming that it bore the brunt of the engagement process rather than sharing the load thru 360 degrees of available casting. That visual "signature" is like a breeding ground from chatter.

Likely sources for this localized hot spot.
1. Uneven pressure plate lift. We tried to explore that visually in your pics, inconclusive.
2. Possible but unlikely actual high spot from machining the pressure plate casting or FW. FW plane can be measured on a surface plate using the crank shaft mounting flange as a base and recording readings at maybe 8 or more spots on OD ID and middle making circles. Or even spinning it and observing.
3. What modifications required using bolts and nuts to assemble the cover to pressure plate? Unknown. But when made in a FACTORY rivets are SOP, not bolts.
4. Undefined errors or damage to the cover, diaphragm spring or even the riveting that holds the spring in the stamping. Requires a very fine tooth comb and hands on inspection.
5. Any clutch supplier should have the equipment to perform a plate lift test that shows at a minimum the plate lift at three points in the fully released condition. specs vary by size but holding .010" variation or less and you're in good shape. We had a computerized test machine that showed the full plate lift vs release stroke force and distance of the release stroke. You could see from beginning to end of the full release system travel.

"The wear and contact pattern on the disc are a concern, and warpage may be a factor"

A bent or warped disc will cause release problems and chatter. But please explain how this disc miraculously managed to start it's contact at exactly the same place each and every time as witnessed by the dark blue hot spots?

"The noise is gear roll over from going from a dual mass to single mass"
I had to inform him that this is an NV5600 and both flywheels (Old and New) are single mass. I mentioned that I've never had gear rollover noise like this on the OEM clutch.

Yup, you got 'em on that one. The NV5600 ended mid 2005 and G56 started mid 2005 give or take. Anybody that is allowed to take a tech call better know that one and not confuse an NV5600 with DMF. On the G56 you can get a pass for confusion but it's almost always due to the customer not knowing which system it has or a counter person with french fry grease on their shirt. Those 8 or 16 spring commercial dampers CAN incorporate a small modification that tip's it's hat in the direction of a crude predamper and knock down the gear noise a little bit but it'll never be as quiet as the OEM fancy torsion damper. Period.

Back in the mid 80's I was doing the R&R on several Dodge front wheel drive platforms so the real clutch engineer could custom tune the torsion damper for drivability, NVH and of course be at a price that the customer would approve. Peter made a modification to the fill plug and added a thermocouple to the fluid reservoir. He never assessed a damper until trans was up to temp. Then in addition to the various drivability tests on of the most telling was the brick wall testing. Yup all warmed up pull up along side a solid brick wall. Engine running, window down, trans in N and let the clutch pedal up ENGAGE the clutch. Now just listen to the trans. Making noise or can't hear it? Repeat many times pedal down, up, listen and repeat. Record your observations.

Your 8 or 16 spring damper is a brute takes a beating and keeps going but as a noise filter (torsion damper) let's say it's not the winner of that contest.

Tried a multi quote but not sure I got it right.

Gary

 

[Darkbloodmon]

OK getting a bit ugly here and I'm just involved cause I take pride in the industry I retired from and proud that some of my cohorts called me a Clutch Guy.

OOPS hit expand to see my ramblings.

I agree it doesn't make sense that the hot spots are so focused, if the clutch causes that on break in it should be uniform all around.

It's not as if the flywheel isn't fully seated or has an abnormally high spot at that location. I checked the runout with a dial gauge multiple times on the outer edge and clutch contact point and no more than .03 thousands of an inch was observed, I'm still waiting for SouthBend's follow up on this spec.

I don't mind some idle noise but its the vibration I feel in the truck that's night and day with the clutch out compared to in.

I'm hoping to get a legitimate and honest explanation.

 

[Tuesdak]

Did you spin the transmission over in 5th and listen for noise?

 

[Darkbloodmon]

Did you spin the transmission over in 5th and listen for noise?

No I have not, what kind of noise am I listening for? I've turned it over in neutral and everything sounds fine. Truck never got above 3rd gear with this clutch in. Does it matter if the T case is mounted? I have it slung up with some straps on an engine hoist.

 

[Tuesdak]

The noise you are tracking down. Just making sure the trans isn't "screaming loud" when turning over by hand for whatever reason.

 

[GCroyle]

DBM,

Want to try this?
Strong workbench and vise. At least a piece of threaded rod 1/2” or bigger, nuts and several washers, larger and enough to clamp against the forged splined hub and nothing else. Tighten the top nut and put this threaded rod in the vise.
The objective is that the hub only is clamped unable to rotate. Nothing else is clamped.

Now put leather gloves on. Grip the facings left and right and try to twist the disc with the hub unable to rotate.

Then care to repeat this with an OE style disc.

See how far you can rotate the disc relative to the hub and report your findings.

Gary

 

[Darkbloodmon]

The noise you are tracking down. Just making sure the trans isn't "screaming loud" when turning over by hand for whatever reason.

I'll put the shifter in and give it a shot.