Luk or South Bend?

[cozinsky]

I have the engine out of my truck and I plan on installing a new clutch when it goes back together. I still have the DMF and want to do a solid flywheel conversion. It looks like I have two options, South Bend or Luk. I can get the Luk kit for about half the price of the South Bend. Is there any difference in quality or is the Luk kit just as good?
What about my upgrades: turbo, intercooler and 110 pump? Will the stock clutch kit hold it or should I upgrade to the organic South Bend kit?

 

[IDIBRONCO]

I like my Luk. I've had the whole thing in three different vehicles and it's still going good. As for the power, I think that the Luk will hold, but if there's any doubt or if you're planning to pull heavy, then it may be a good idea to upgrade. It would be MUCH better to pay for the South Bend now than have to pull your Luk out and then put a South Bend in it's place in 6 months or a year. Maybe someone else will have more experience than I do with how much the Luk will hold up to.

 

[IDIoit]

a southbend is noticeably stiffer.
ran one on my build at first.
switched to luk..
luk is fine till 3-350+ hp
south bend also comes in psd diameter

 

[u2slow]

Isn't Luk just copying the stock SMFW 99-02 PSD setup for IDI use? That's the case for the OBS PSD... my '95 SMFW conversion actually used a stock '99 flywheel.

I was asked to do a southbend for buddy's work on a 94 IDIT - he didn't mind the stiffness, but his co-worker never stopped whining about it. No other issues.

I prefer OE/jobber parts for the price point, and don't seem to wreck them... even with power mods.

 

[Kevin 007]

I have only used Luk's. several of them. Never had a failure. They are loud/rattley when idling in neutral however

 

[IDIBRONCO]

They are loud/rattley when idling in neutral however

I haven't noticed that with mine, but I may just be used to it. I also first installed it if my first 85 F250 during the ZF5 swap and it may be rattley and I just can't tell the difference. It took me a long time to even realize what the gear rollover noise was. I thought that it was normal and didn't really pay any attention to it.

 

[cozinsky]

Guess I'll go with the Luk. Its quite a bit cheaper and my gf drives the truck some too and I know she wouldn't be happy with a stiff pedal.
I'm familiar with rollover noise. I plan on overfilling it a quart and hopefully that will help.

 

[Kevin 007]

Ya the stiffer clutches are not easier on the hydraulics either.... which isn't great

 

[onetonjohn]

Unless you have some compelling reason to not go with Luk on these trucks, I would always choose Luk. BTW - I used to work in a clutch shop and have literally installed hundreds of clutches on these trucks. Be sure to turn the flywheel.

 

[The_Josh_Bear]

One thing that eliminates gear rollover noise entirely is to raise the idle RPM.
I did that years ago with my LuK SMF and with a standard fill of Redline MTF I have zero rollover noise ever. Once I adjusted it back because I forgot why it was around 900rpms all the time. That lasted about 2 minutes! As soon as I started it I hated that noise. Drove from one side of the house to the other and changed it back.
I spend almost zero time in traffic so it's not like it hurts the fuel economy and only helps engine health.
Also helps cold starts!

 

[nelstomlinson]

south bend also comes in psd diameter

Since it's not totally off topic here, does somebody have a build thread for putting a psd clutch behind one of our engines? I've been thinking I could have the machine shop drill mounting holes in a IDI SMF for a bigger pressure plate.

 

[onetonjohn]

There is a Luk upgrade kit to 12" clutch that is bolt on. You don't have to go PSD.

 

[cozinsky]

There is a Luk upgrade kit to 12" clutch that is bolt on. You don't have to go PSD.

Do you happen to have the part number for that kit? The Luk kit I'm looking at is 07-131 and it says the disc diameter is 12.25".

 

[IDIoit]

south bend clutches are 13"
comes with everything to simply bolt on

 

[u2slow]

Since it's not totally off topic here, does somebody have a build thread for putting a psd clutch behind one of our engines? I've been thinking I could have the machine shop drill mounting holes in a IDI SMF for a bigger pressure plate.

Its been ~15 years since I went through it on my '95 F350, so bear with me...

The native/OE SMFW diesel clutch from a 99-02 features a bigger input shaft (ZF5 vs ZF6).

The Luk conversion of the day for the OBS (PSD) was apparently the 99-02 Superduty flywheel and pressure plate, with a custom/alternate disc for the smaller ZF5 input. The catch was Luk wanted to sell the whole package. Through specific channels and pestering, you could get the basic repset clutch kit (without flywheel) on the presumption you wore out your clutch since the conversion. (They wouldn't sell just the disc). What my buddy did was score me a used SD flywheel and that Luk repset kit.

To translate that over to IDI fitment... your SMFW would have the emulate the factory 99-02 one (on the clutch side) for that particular Luk kit I used to work.