Johnny Joint grease—an experiment

I wonder why the emphasis on the high moly content for johnny joints? Usually you see moly content required when a high load is concentrated in a small area of metal to metal contact...the entire load is concentrated on basically what amounts to a single point or a line where the spherical or cylindrical roller meets the race or two gear teeth wipe across one another. A johnny joint doesn't really produce the same situation because the load gets spread out across a much larger surface between the steel ball and the poly shell.

I'm not necessarily questioning the need for molybdenum disulfide in a JJ application because I believe Currie/Rockjock probably didn't arrive at that conclusion out of nowhere; but I'm very interested in what function the moly acts in a JJ. Or maybe the recommendation is there because that's what they've used and haven't tried something else?

I installed my SwayLOC today and wouldn't you know it, the lubricant they recommend and provided for the inside of the bushings where the steel sway bar rides was the silicone Energy Suspension Formula 5 Prelube.
 
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I wonder why the emphasis on the high moly content for johnny joints? Usually you see moly content required in metal to metal contact, when a high load is concentrated in a small area - like wheel bearings, u-joint caps, winch gearboxes...the entire load is concentrated on basically what amounts to a single point or a line where the spherical or cylindrical roller meets the race or two gear teeth wipe across one another. A johnny joint doesn't really produce the same situation because the load gets spread out across a much larger surface between the steel ball and the poly shell.

I'm not necessarily questioning the need for molybdenum disulfide in a JJ application because I believe Currie/Rockjock probably didn't arrive at that conclusion out of nowhere; but I'm very interested in what function the moly acts in a JJ. Or maybe the recommendation is there because that's what they've used and haven't tried something else?

I installed my SwayLOC today and wouldn't you know it, the lubricant they recommend and provided for the inside of the bushings where the steel sway bar rides was the silicone Energy Suspension Formula 5 Prelube.
Moly has a speed problem. You wouldn't use it on wheel bearings or driveshaft u-joints. When the surface speed gets high enough the moly shingles break up and become abrasive. It is best in a high force high load low speed scenario.

I will say that if you try any other grease that we've tested in JJ, it is immediately obvious that the break away torque reduction of the CV-2 red moly is far better than anything else.
 
Moly has a speed problem. You wouldn't use it on wheel bearings or driveshaft u-joints. When the surface speed gets high enough the moly shingles break up and become abrasive. It is best in a high force high load low speed scenario.

I will say that if you try any other grease that we've tested in JJ, it is immediately obvious that the break away torque reduction of the CV-2 red moly is far better than anything else.
That's interesting, only from the simple fact that Honda produces a high moly grease for the ring and pinion of their shaft drive motorcycles. It's something like 60 percent moly and expensive as hell. I have a mini tube here...
 
Moly has a speed problem. You wouldn't use it on wheel bearings or driveshaft u-joints. When the surface speed gets high enough the moly shingles break up and become abrasive. It is best in a high force high load low speed scenario.

I will say that if you try any other grease that we've tested in JJ, it is immediately obvious that the break away torque reduction of the CV-2 red moly is far better than anything else.

Good to know. I did notice the silicone prelube was super sticky and viscous so an increase in breakaway torque over that of CV2 would be expected.

What is the real world impact of the reduction in breakaway torque? Is it something that would be an acceptable sacrifice in exchange for a lubricant that lasted longer than a petroleum based moly in high-clay environments?
 

Molybdenum (Moly) Grease​

Greases containing molybdenum disulfide as an additive are used in many heavy-duty, load-bearing, demanding situations such as in construction equipment, railways, farm machinery, etc. Specific everyday uses for molybdenum grease include:

  • CV joints
  • Ball joints
  • Steering linkages
  • Pivot pins
  • Kingpins
  • Worm and helical gears
  • Splines
  • Pinion gears
As well as just about any other heavily-loaded, low-speed application. It is also serves as a good multi-purpose grease. Its exceptional ability to reduce friction, however, makes it unsuitable for high-speed bearings (such as needle or roller bearings), as the rollers/needles need a small amount of friction in order to rotate a full 360° and perform as they should. Otherwise, they develop flat areas along the length of the rollers/needles and eventually stop rotating, thereby reducing the bearing's performance and resulting in a sooner than expected replacement.
 
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Molybdenum (Moly) Grease​

Greases containing molybdenum disulfide as an additive are used in many heavy-duty, load-bearing, demanding situations such as in construction equipment, railways, farm machinery, etc. Specific everyday uses for molybdenum grease include:

  • CV joints
  • Ball joints
  • Steering linkages
  • Pivot pins
  • Kingpins
  • Worm and helical gears
  • Splines
  • Pinion gears
As well as just about any other heavily-loaded, low-speed application. It is also serves as a good multi-purpose grease. Its exceptional ability to reduce friction, however, makes it unsuitable for high-speed bearings (such as needle or roller bearings), as the rollers/needles need a small amount of friction in order to rotate a full 360° and perform as they should. Otherwise, they develop flat areas along the length of the rollers/needles and eventually stop rotating, thereby reducing the bearing's performance and resulting in a sooner than expected replacement.

My understanding of moly grease application has improved a lot over the last couple of hours. A JJ likely doesn't reach anywhere near the loads of any of the stuff you listed but the friction properties help the spherical ball articulate inside the JJs poly shell more freely.

Now just to understand the real world benefit of a low breakaway torque, or from a other angle, can another lubricant still be usable despite not matching the breakaway torque of a moly product?
 
My understanding of moly grease application has improved a lot over the last couple of hours. A JJ likely doesn't reach anywhere near the loads of any of the stuff you listed but the friction properties help the spherical ball articulate inside the JJs poly shell more freely.

Now just to understand the real world benefit of a low breakaway torque, or from a other angle, can another lubricant still be usable despite not matching the breakaway torque of a moly product?
My empirical evidence suggests that even though the energy suspension stuff has a higher breakaway force, the arms still move freely with the weight of the Jeep on them.

I have another trip planned next weekend to mount holly (a private park where the ”mount” is a giant concrete hill they poured to replicate something in Moab). So far, so good on my joints.
 
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My understanding of moly grease application has improved a lot over the last couple of hours. A JJ likely doesn't reach anywhere near the loads of any of the stuff you listed but the friction properties help the spherical ball articulate inside the JJs poly shell more freely.

Now just to understand the real world benefit of a low breakaway torque, or from a other angle, can another lubricant still be usable despite not matching the breakaway torque of a moly product?
No benefit, just tells you that grease works very well at reducing friction, nothing more.
 
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My empirical evidence suggests that even though the energy suspension stuff has a higher breakaway force, the arms still move freely with the weight of the Jeep on them.

I have another trip planned next weekend to mount holly (a private park where the ”mount” is a giant concrete hill they poured to replicate something in Moab). So far, so good on my joints.
Have you been in the clay much to see how resistant it is to getting the base sucked out?

I didn't get into much mud but the prelube I used on the energy suspension poly bushings in my 280z in 2002 never squeaked in 4 years as a daily driver.
 
Have you been in the clay much to see how resistant it is to getting the base sucked out?

I didn't get into much mud but the prelube I used on the energy suspension poly bushings in my 280z in 2002 never squeaked in 4 years as a daily driver.
I went a month ago and played in the mud. I didn't get stuck, but this was pretty typical
20211009_180339-2.jpg
 
This was Drummond island, right? That looks like a screenshot from a Jeep commercial.
Correct. My wife managed to grab one of the best shots of the trip, bouncing around in the back seat of my Jeep, with her cell phone, through the rear window!
 
I want to see the Z.

Hate to disappoint, but it was a beater in appearance. I spent all my college student budget on the mechanicals which left enough for a rattle can paint job. Flat black was the color du jour back then.

rightfront.jpg


Digital photography entered my life roughly halfway through ownership so I don't have nearly as many photos as I'd like, in fact the only engine photo I can find was pre-paint, where it's obvious that the body panels came from at least two different cars.

leftengine.jpg


I built the engine with flat top pistons out of a 280zx and milled the head a bit for a 10.5:1 CR, a moderate cam and triple weber carbs, 6-1 longtubes, matched it to an 8lb flywheel and a 5 speed and 3.90 rear differential (vs the 4 spd and 3.55 it had), also out of a 280zx.