Which clutch do you think I should get?

[KATOOM]

I tow a 14k 5th wheel in the mountains and last weekend my stock clutch started to slip.  The only "hp" related items on my truck is an aFe intake, 4" exhaust, and EZ so I should be around 300 hp at best.  I called Southbend and Valair and their prices are considerable in difference which has me wondering what I'm overlooking.  I know they're both very reputable clutches in these trucks so.....

 

Valair's NMU70279-01-5SCE is rated for 400 HP.  New 13" flywheel and organic clutch material.  Aprrox $650.

 

Southbend's 13125-OKHD is rated for 425 HP.  New 13" flywheel and organic clutch material.  Aprrox $850.

 

I dont have plans for any HP add on's other than I "may" look at 50 HP injectors someday to help towing a little.  I have no desire to reduce any drivability so thats all the HP I want.  Which clutch would anyone suggest or may already have?  Thanks guys.

[MnTom]

I would really look at the Valair since it is less money and rated for more than what you are oing to be at for power.

[AH64ID]

Wow, those prices seem really low! The OKHD my dad put in, and the OFE input in where both a bit more than that. Mine didn't even have a flywheel.

The OHD gets my vote, it's a great clutch and when the time comes for me to change clutches I will detune about 15hp and go that route.

[KATOOM]

Why detune?

[AH64ID]

Why detune?

So I wouldn't be at the torque rating.

[Dave3500]

My South Bend w a 13' is awesome!

[rancherman]

My South Bend w a 13' is awesome!

Dave,  did you get the flywheel  with the  clutch kit... or  did it come with the  trans?

 

I'm   'zeroing'  in on   parts  for my project..  and   looking pretty hard at  Southbend.      I   have the  6 speed,  but the  donor truck  still has  the  5 speed  flywheel..   10.5 inch?       I  see     we can  buy the  disk with the  1 3/8ths input.. (mine)   and   the  larger  pressure plate,  but  need to redrill the  flywheel.      I'd rather not   do that,   a new  flywheel   just  seems   smarter...

$ 921  for the  'kit'  W/flywheel.     1947  OFEK   

$727   for  the  kit  WO  flywheel..  1947 OFE         475 HP rating         I  could   probably find a  salvage yard  flywheel  for  a lot less,   but by the time it's  faced,    $80 bucks,  It's still a    used  flywheel, from  unknown abuse..   Question is,    Do I feel lucky?     

Edited August 21, 2014 by rancherman

[KATOOM]

My clutch is still on its way and UPS is supposed to deliver it on Friday.  The 5 speed trucks have a 12.5" clutch with a 1.25" input shaft.  The clutch I ordered comes with a new 13" flywheel and clutch but still has the 1.25" input shaft.  I could have upgraded to the larger input shaft for another $300 but I have no intentions of making that kinda HP.  If I ever get the 50-60 hp injectors I'm wanting then that will be all the power plans I have for this truck.  And the current clutch I'm getting is supposed to handle that added power too.

Edited August 21, 2014 by KATOOM

[Gamble]

I did the Valair Kevlar/Ceramic...I think its 500HP rated...  I tow a fair amount its been a great clutch so far.  I would imagine as good as this one does, you should have a great experience with the one you ordered.  I am hoping to just breach the 450HP mark in the future so I went safe.  If I ever go to bigger HP I will get a dual disc and try one out.

[KATOOM]

I was told that I didn't make the HP for the K/C clutch and it would burn its self up and drive horrible. The one I'm getting is rated to 425 at the tires. I'm lucky if I make 300 right now.....

[MnTom]

I was told that I didn't make the HP for the K/C clutch and it would burn its self up and drive horrible.

Ok, I may not be the brightest bulb on the string, so explain to me how the LACK of horse power will cause a clutch to burn up??

[KATOOM]

Dont worry Tom.....  You're not alone because I'm still a little confused about this myself.  So it was explained to me, if the engines HP/torque is not high enough to slip the clutch a specified design amount for the material used during day to day driving then the clutch will be overly grabby and the material will not hold together like its supposed to and get hot.

 

I fully understand why a clutch unnecessarily stronger than the HP generated "and" the weight of a vehicle would cause the clutch to be aggressively grabby, but I still dont understand why it would burn it up.  Matter of fact during those conversations, I asked the clutch people if I bought the high rated clutch and simply started off in 2nd gear more often would that do the same thing, and the answer was no.   Then I tried to say that this made no sense to me because the way I was looking at it was.....  If you take two identical trucks weighing in at around the same weight.  Both have the same engine but one makes 300 hp and one makes 500 hp.  Under those circumstances then the clutch should see the same wear and slippage upon taking off from a stop.  It shouldn't matter if the one engine made almost double the HP since both trucks still weighs the same as the other.  But they kept saying no it doesn't work like that.  So I dont know.....

[MnTom]

I don't understand it either. I was ALWAYS taught to not slip the clutch. If grabby was a cause for them to burn then why are ceramic clutches made? If you follow their train of thought then you would be burning up flywheels and pressure plates with them.

[rancherman]

Remember  back in  'the day'....  

 

A  new  clutch  almost needed to  be   'put against a  tree'  and   burnt in..   well,  not quite  burned...        I remember  as  a lad,  hearing  my   'heroes of the 'hood'    talking about  their  trucks/cars  with a new clutch  being  grabby as  heck... and  they  ' burned it  in'....  literally  against a tree.

 

Thinking back,   I'll bet they weren't too  careful  with  greasy  paws,  and   that  may have been  some of their  problem..  Or   they didn't  grind  the  flywheel,  and   the  disk  was   'making friends the hard way' with  flywheel!

 

I can see  the potential   for  a  long  break in   period with a  over rated  clutch.      (not  the  over-rated version of  bragging,  but   the  power rating)

If it  grabs and  chatters  every time,     might  get some   chunking of  friction material...  If  that  chunk is  wedged  and  is  the sole  driver...  yah,   I can see  'burning'..   because it'd  be holding  part of the pressure  plate  askew..   temporarily  anyways.    It  doesn't take  a very large crumb.

 

Oh, btw,   Do these  aftermarket performance  clutches   come with a recommended   finish grind  for the  flywheel?

 

I'm  with you Tom,    'slipping'    is  for   just the  brief  moment  at   roll out..       If  I find myself   'feathering the clutch' it means  I'm in the wrong gear,  or  RANGE!

Rule of thumb  with  a load...  If  right foot is  working... the left is resting

Edited August 22, 2014 by rancherman

[MnTom]

Rule of thumb  with  a load...  If  right foot is  working... the left is resting

That was the way I was taught with a diesel. Even when I was in a semi the clutch was released at an idle no matter what. I have gotten as much as 122,000 pounds (might have been more, but that was all I could permit with the axles) at an idle. Once the truck was moving I never needed the clutch.

[rancherman]

oh geez,  I'll never forget  the  day  my  FIL  came driving up  with his  'new' purchase...  the  2000  ram  I currently have in my sig..

 

They  pulled into the drive,  engine racing..  ( but to his defense,  they just  traded  a   ford  gasser with  5.0 and  manual trans)  some habits are hard to break!!

 

anyway..  it took about  6 months of me    chewing him out for  bringing up the  rpm  and   slipping the clutch!!     especially  with a load!

I think  the  2 stock type clutches later   finally   'sank home'     (in  the first year!)

 

One day,   I was  behind the wheel,   stock trailer with 12 cows..  so   about  20k  behind the  pickup...   We were in town,  sitting under the  stop light.  Idled away...   I looked over at him and  said "see??"   plenty of torque,  don't need to even  touch the  fuel..

......... geez,   I hate it when  I prove a point to him~

 

The only time I can ever  see  slipping being good,  is  when you are on the starting line of  a drag race, or  sled pull...  and  you need to  light the  turbo...     Crower  makes  a pretty good  slipper clutch for just that!

[Gamble]

When I purchased mine, I spoke extensively with Valair...they did not ever mention anything about that....but rather told me I could grow into it, as i only had the Edge at the time.  i just installed my 100's today, so its not like I been making a lot of power up until this point.  I ll let you know if anything changes now that I have thrown some more horses down, as soon as I ensure I have no recurring leaks or weeping anyway.

[KATOOM]

Well thats just interesting.....and kinda frustrating too.  In all honesty I couldn't have been more clear on my intentions and needs from this new clutch.....and what I have and what weight I pull around.  My truck is "maybe" making 300 hp currently and I "maybe" installing some 50-60 hp injectors some day down the road.  But with all that said, my biggest concern when talking to Valair and SB was that I'm hauling around 14k lbs behind me in the hills and under full throttle conditions.  I do NOT want this new clutch to slip, even with those bigger injectors, otherwise I'd be one upset customer.  SB said that without a doubt the organic clutch I'm getting will hold 425 hp at the wheels and pull 20k lbs.  What can I say to that?  SB is a top notch company and I cant imagine why they'd lead me astray since cost wasn't part of the discussion.

[Gamble]

I can't imagine they would lead you astray either, especially since they talked you into the cheaper one.  Maybe the difference is I will rarely tow over 12K.  I pull a trailer a lot, but rarely have to go pick up a load like that.  I wouldn't mind if mine got smoother, but I am and have always been more than happy with mine just as it is.  As I said before, I usually start in 1st because its a touch jumpy taking off in 2nd unless I'm loaded, then its no big deal, but I still use 1st out of habit.  One thing I will say though, its very easy to pick up power out of these trucks, even somewhat unintentionally.  I have to do some looking to see where I should be at in terms of WHP after putting in my 100's vs going to a slightly larger snail down the road vs where I was yesterday...... I don't wish to put in a new clutch anytime soon so I need to see if I should tip toe through the tulips or run them down with juvenile apathy.