LUK/Exedy 07076 clutches

[LCAM-01XA]

This is what they look like:

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11" disc, 1-1/4" splines (ZF5 size), supposedly for a DMF setup... However, notice the disc has springs in it! Most other DMF clutches have what looks like solid hubs on the disc, this however has the same spring configuration you'll find in your typical 4-speed kit (even for a diesel T19). And 4-speeds use solid flywheels, not DMFs. So if this works like a 4-speed clutch, but fits a ZF5 input shaft, what's to stop one from using it with the 4-speed flywheel to drop a ZF5 in place of the 4-speed? Even the pressure plate has the proper 6 bolts to match the 4-speed flywheel...

Yes the ZF will probably moan and whine at idle, not enough springs in that clutch as compared to proper SMF-conversion discs, but overfilling it with Castrol synchromesh oil (liquid gold I tell ya!) should keep that to a minimum. Yes there are proper SMF conversion kits out there, 12" in size even, however they are north of $300 - the recipient vehicle will never be making tons of power so while the extra holding power of a 12" clutch is nice for this particular application it's not worth the extra $200 (and $200 buys a mountain weekend's worth of fuel). And our flywheel was already machined not that long ago, don't really wanna buy another one unless absolutely must have to... The whole idea is to keep this swap as low-cost as possible or we risk blows to the vacation budget and we can't have that!!!

Any thoughts/opinions on the matter?

 

[BDCarrillo]

Not speaking directly to the ZF5 but just general clutch tech: As long as the whole assembly is thick enough that the throwout bearing is still within a good range of motion, oughta work. Are there any locating studs on the pressure plate that may not match up? Does the pressure plate bolt circle match?

I'm guessing that setup was meant for a gasser, but with a gentle foot and a light load in theory you oughta be fine.

 

[LCAM-01XA]

Actually no, these clutches above are for IDIs with a factory DMF., not gassers. Thing is, they were the only ones listed for '87 trucks, all the others are '88-'94. '87 being the only factory 5-speed 6.9 as opposed to all the later 7.3s, I suppose engine size makes some difference - the 6.9 is the only one that got the spring-equipped cluch disc, all the 7.3s got discs with solid hub. Like I said, it looks exactly like the 4-speed setup we're running right now, and that one sees neither gentle foot nor light loads on fairly regular basis. And diesel 4-speeds have nearly identical gears as 1-4 in a diesel ZF5. Dunno on the pressure plate BCD and locating dowel pins though, that is a valid concern that I have as well, hence why I posted this thread - hoping that maybe someone had this idea before us and tried it and could verify yay or nay on how it all works together.

 

[Ford F834]

Actually no, these clutches above are for IDIs with a factory DMF., not gassers. Thing is, they were the only ones listed for '87 trucks, all the others are '88-'94. '87 being the only factory 5-speed 6.9 as opposed to all the later 7.3s, I suppose engine size makes some difference - the 6.9 is the only one that got the spring-equipped cluch disc, all the 7.3s got discs with solid hub

The 6.9 pressure plates mount with 6 bolts, the 7.3 mounts with 8 bolts. That is the only difference. Every 7.3 DMF clutch I have seen looks exactly like your picture, with one row of springs in the hub. I have never seen one without springs. The clutch in the picture looks like a standard DMF replacrment clutch to me. The SMF conversion clutches have two sets of springs...

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[LCAM-01XA]

Alright, so the 7.3 DMF clutch discs are then essentially the same thing as those used with the 6.9 solid flywheels, just larger hub for the larger ZF input shaft. That makes things easier. Now, take a look at this here thing:

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This is Luk 07100, a 12" upgrade for DMF trucks. And here's another one, this one standard 11" DMF clutch by AMS (part # 07504):

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This is what I mean by solid hubs, there are no springs in there, none at all. One of that behind a 6.9 flywheel would be quite horrible, whereas the spring-equipped ones from LUK/Exedy/Valeo should, in theory, behave exactly like their 4-speed cousins.

And now let's make this a true team effort - does anyone have a DMF they can measure? I have a 6.9 solid flywheel for a 4-speed, I plan on digging it out of its hiding spot tomorrow and measuring it. What we should be comparing, are the circle diameter for the bolts that hold the pressure plate on (so measure between any two bolt holes that are clear across the flywheel from each other), and the same thing for any locating dowel pins there may be. I suppose size (diameter) of said bolt holes and dowel pins may also be helpful. So, anyone wanna play?

 

[kcwright1979]

I will try to get to mine this afternoon and measure it for you

 

[catbird7]

FORD F834, you mention the SMF come with two sets of springs in the clutch disc. The SMF conversion I bought was supplied with a clutch disc having only one set of springs. Looks like a typical gasser clutch. The gear roll over noise with this set-up is terrible! I have seen the discs you are referring to with two sets of springs and I wonder if they reduce the amount of "gear roll over" noise? Do you have a photo illustrating one of these discs with two sets of springs? Manufacturer? Part number?

 

[TahoeTom]

My 6.9 solid flywheel was easy to get to. There are no locating pins. Being 6 holes they arent directly across the diameter. The diameter of the machined surface is 14 7/8. The holes are 1" from the edge so bolt circle would be 12 7/8. ctc of mounting holes is between 3 1/2 and 3 9/16 or about 3 17/32. Maybe it is a metric number. I get 90.5 mm ctc. Pilot bearing id is .68" and the od is 1.35".

 

[Ford F834]

FORD F834, you mention the SMF come with two sets of springs in the clutch disc. The SMF conversion I bought was supplied with a clutch disc having only one set of springs. Looks like a typical gasser clutch. The gear roll over noise with this set-up is terrible! I have seen the discs you are referring to with two sets of springs and I wonder if they reduce the amount of "gear roll over" noise? Do you have a photo illustrating one of these discs with two sets of springs? Manufacturer? Part number?

I don't know if my picture is showing up for you, but that is my photo of the actual friction disc for the SMF conversion that I did. I used the LuK SMF conversion kit #07225, it was $319 from RockAuto and included the flywheel. It has the 8 bolt mounting pattern of a 7.3 but has perfect balance behind a 6.9 as well. I used 50 wt synthetic ATF that I got from a big rig service station, and gear roll over is almost unnoticeable.

 

[LCAM-01XA]

My 6.9 solid flywheel was easy to get to. There are no locating pins. Being 6 holes they arent directly across the diameter. The diameter of the machined surface is 14 7/8. The holes are 1" from the edge so bolt circle would be 12 7/8. ctc of mounting holes is between 3 1/2 and 3 9/16 or about 3 17/32. Maybe it is a metric number. I get 90.5 mm ctc. Pilot bearing id is .68" and the od is 1.35".

That jives with the numbers I got:

- all bolts are about 6.5" away from the center, so around 13" BCD.
- the bolts that are closer together are indeed 3-17/32" apart.
- the bolts that are far from each other are about 9" apart.
- the bolts appear to be either M8 or fine 5-/16" thread.

Didn't think to measure the pilot bearing but I'm glad you did. The ZF shaft pilot is 0.67" according to my calipers, so at least that should work just fine.