Author Topic: Clutch problems  (Read 627 times)

0 Members and 1 Guest are viewing this topic.

BigBlueIron

  • Jr. Member
  • **
  • Posts: 79
    • View Profile
Clutch problems
« on: July 11, 2018, 10:13:12 AM »
Well I have a problem, clutch slipped on me last night during some "testing" so I guess that's a good problem right??  :)

 I rolled hard in the throttle at about 50mph and it let go probably around 70 or so. In 4th gear so 1:1 with 4.27 rear gear. If anyone wondered.

Current clutch stocker 3 finger, 11" if memory serves, fresh grind on the flywheel. Works and feels great, nothing wrong at all with it just couldn't hang on. What is the capacity of a stock type clutch? Or what kind of power does it take to blow through one while at speed? No idea what this engine makes power wise, be nice to have a half assed idea.

When the time comes to change it I plan on doing an SFI flywheel, I'm guessing it will be simpler to buy all at once anyway. McLeod?? Ive heard Centerforce is junk. Only performance type clutches Ive dealt with are multi disk slippers and company's that specialize in those.

blykins

  • Hero Member
  • *****
  • Posts: 1697
    • View Profile
    • Lykins Motorsports
Re: Clutch problems
« Reply #1 on: July 11, 2018, 10:23:30 AM »
350-400 hp is what the stock style replacements are good for.

You're good in selecting a McLeod or RAM for your next go-round.

Once you make it slip, it will start slipping more and more.
Brent Lykins
Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com
502-759-1431
Instagram:  brentlykinsmotorsports

BigBlueIron

  • Jr. Member
  • **
  • Posts: 79
    • View Profile
Re: Clutch problems
« Reply #2 on: July 11, 2018, 10:37:53 AM »
I forgot to mention that the current pressure plate has the counter weighted fingers.

Thanks for the recommendation,

Yep, but just plan to drive it for awhile. Just got it on the road recently so I'll just lay off the boost some.

BattlestarGalactic

  • Sr. Member
  • ****
  • Posts: 423
    • View Profile
Re: Clutch problems
« Reply #3 on: July 11, 2018, 10:49:46 AM »
so I'll just lay off the boost some.

Yup, there's the problem...... ;D

How much boost?

BigBlueIron

  • Jr. Member
  • **
  • Posts: 79
    • View Profile
Re: Clutch problems
« Reply #4 on: July 11, 2018, 11:25:09 AM »

Yup, there's the problem...... ;D

How much boost?
[/quote]

More than safe, smart or sustainable, by a lot..  Its a 30 pound gauge and will use all of it if you want it to...

blykins

  • Hero Member
  • *****
  • Posts: 1697
    • View Profile
    • Lykins Motorsports
Re: Clutch problems
« Reply #5 on: July 11, 2018, 11:33:33 AM »

Yup, there's the problem...... ;D

How much boost?

More than safe, smart or sustainable, by a lot..  Its a 30 pound gauge and will use all of it if you want it to...
[/quote]

Well poop the bed.

You have a twin disc in your future.
Brent Lykins
Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com
502-759-1431
Instagram:  brentlykinsmotorsports

BigBlueIron

  • Jr. Member
  • **
  • Posts: 79
    • View Profile
Re: Clutch problems
« Reply #6 on: July 11, 2018, 11:52:50 AM »

Yup, there's the problem...... ;D

How much boost?

More than safe, smart or sustainable, by a lot..  Its a 30 pound gauge and will use all of it if you want it to...

Well poop the bed.

You have a twin disc in your future.
[/quote]

lol No, it will be limited around 15.

Question Brent, Could I just swap the friction for say the RAM 300/900 disc? I always thought the counter weighted long style pressure plate I have was a good unit.

BTW anyone have a good used SFI flywheel for sale?

blykins

  • Hero Member
  • *****
  • Posts: 1697
    • View Profile
    • Lykins Motorsports
Re: Clutch problems
« Reply #7 on: July 11, 2018, 11:57:50 AM »
Depends on which pressure plate it is.  Some disc manufacturers use a proprietary disc thickness and the air gap won't be right with different pressure plates.

A 900/300 RAM disc would be rated for 550 hp with the correct pressure plate.

Another note to make is that individual component pricing is unreal compared to kit pricing.  The price of a clutch disc by itself would be way over half the price of a complete kit and you'll probably find that your pressure plate has been a little hot anyway.
Brent Lykins
Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com
502-759-1431
Instagram:  brentlykinsmotorsports

BattlestarGalactic

  • Sr. Member
  • ****
  • Posts: 423
    • View Profile
Re: Clutch problems
« Reply #8 on: July 11, 2018, 12:15:08 PM »
At what RPM is 70 mph?   Those CW levers are fine, but if you aren't high enough on rpm then they will not give full clamping capacity.  Thus it is harder with a boosted vehicle to run a clutch(at least a soft one).  They have to be aggressive because they have to hold at low rpm/high boost.

The dual disc unit just doubles up the surface area, effectively giving you more clamping force with less base pressure then a single disc.

fekbmax

  • Hero Member
  • *****
  • Posts: 1061
    • View Profile
Re: Clutch problems
« Reply #9 on: July 11, 2018, 12:54:17 PM »
What's the base pressure ? Have you added any counter weight ? What type of disk ? If it's a counter weight then i think it most likely would have adjustable base.
Keith.  KB MAX Racing.

BigBlueIron

  • Jr. Member
  • **
  • Posts: 79
    • View Profile
Re: Clutch problems
« Reply #10 on: July 11, 2018, 12:58:53 PM »
Depends on which pressure plate it is.  Some disc manufacturers use a proprietary disc thickness and the air gap won't be right with different pressure plates.

A 900/300 RAM disc would be rated for 550 hp with the correct pressure plate.

Another note to make is that individual component pricing is unreal compared to kit pricing.  The price of a clutch disc by itself would be way over half the price of a complete kit and you'll probably find that your pressure plate has been a little hot anyway.

Not worth messing with, pull it out before I ruin it and save it for a stock pickup. Brent Ill shoot you an email.

At what RPM is 70 mph?   Those CW levers are fine, but if you aren't high enough on rpm then they will not give full clamping capacity.  Thus it is harder with a boosted vehicle to run a clutch(at least a soft one).  They have to be aggressive because they have to hold at low rpm/high boost.

The dual disc unit just doubles up the surface area, effectively giving you more clamping force with less base pressure then a single disc.

Well I did some quick math with my set up and that would be 3350rpm at 70 I think my mph is off. I was just guessing as I have no speedo just a tach, which is all I need anyway, but it was pulling like a freight train and looking at the tach wasn't on my mind lol.

You know you guys make a point on the dual disc. Since I really need it all anyway how much would it cost? Probably not much. Plus a street type dual disk might be more street friendly. Just a guess though.

What's the base pressure ? Have you added any counter weight ? What type of disk ? If it's a counter weight then i think it most likely would have adjustable base.
No idea on base pressure nor is it adjustable. Organic disc nothing special. It is the fixed weight, only good way to add weight to them is weld them up.

blykins

  • Hero Member
  • *****
  • Posts: 1697
    • View Profile
    • Lykins Motorsports
Re: Clutch problems
« Reply #11 on: July 11, 2018, 01:05:14 PM »
What trans?
Brent Lykins
Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com
502-759-1431
Instagram:  brentlykinsmotorsports

BattlestarGalactic

  • Sr. Member
  • ****
  • Posts: 423
    • View Profile
Re: Clutch problems
« Reply #12 on: July 11, 2018, 01:29:51 PM »
What's the base pressure ? Have you added any counter weight ? What type of disk ? If it's a counter weight then i think it most likely would have adjustable base.

Lots of stock pressure plates have CW hanging on the levers(I've used them many years back), but none are adjustable base pressure.  Only aftermarket, racing clutches have adjustable base pressures.


Well I did some quick math with my set up and that would be 3350rpm at 70 I think my mph is off. I was just guessing as I have no speedo just a tach, which is all I need anyway, but it was pulling like a freight train and looking at the tach wasn't on my mind lol.


Ya, at 3400 rpm, I'm pretty sure that CW is no where near full potential.  Like I mentioned, a dual disc will get you the surface area(without insane pressure=heavy clutch pedal) needed to support that kind of power at low rpm.  If not, you will have to get a pretty stiff stock single pressure plate to hold the same power.

fekbmax

  • Hero Member
  • *****
  • Posts: 1061
    • View Profile
Re: Clutch problems
« Reply #13 on: July 11, 2018, 01:55:00 PM »
Yeah, my bad. I miss understood. Thought it had adjustable CW, not fixed. Was wondering how that coulda been a stick PP.
Keith.  KB MAX Racing.

BigBlueIron

  • Jr. Member
  • **
  • Posts: 79
    • View Profile
Re: Clutch problems
« Reply #14 on: July 11, 2018, 04:22:10 PM »
What trans?

Which one? Its got 2! lol Advance Adapters Road Ranger in front of an NP435. As far as the clutch is concerned its the same as a stock setup with a 435. Shifts like crap but that's probably a good thing, If I would have went C6 I'm sure I would have wrecked it by now.