Of Flywheels and Threadlockers.

The day after Christmas, 2007? 2008? meh. Some time ago, Ryuto held out his hand for me and offered to get my clutch done for me. I was still a little wet behind the ears and needed a hand. Gotta love DSMers
After tearing my old SPEC Stage 2+ and stock flywheel out of there we installed a Competition Clutch 2100 and CC chromoly flywheel. 2700lbs. PP + Full face organic/kevlar weave disc.

I actually loved the clutch but it soon developed a very harsh engagement, literally no slipping was possible unless you didn't mind revving out at a stand still. It became an on and off switch.
Years later, right up until last August, actually, the clutch worked like that with no other issues. One (hot)day the clutch began to slip at stop lights. Never on the hwy, or when trying to put power down but getting around town was getting less and less practical. It was time to come out.

Since I more or less destroyed my SPEC Stage 2+ disc (down to the rivets) I was keen to find out how well the CC combo fared with 50-60k on the clock.

This is what I found.

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Notice anything? Notice anything.. else?

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Similar story.
So what went on here?

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Well, I was missing a spring and the others had seen better days..

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So, sure. My disc had seen better days but the friction surface was not beyond service limits and overall looked pretty good considering some of the things I'd done to it. I'd say it held up really well for having lop-sided mating surfaces.

Moving right along...
This is AFTER I cleaned off the surface a little. All that junk and uneven-ness on the crank surface is loctite. Dried loctite.

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I don't know what happened to the shot I had of the flywheel backside but it was caked up pretty good with loctite.
Ironically enough, I'm betting that clutch would have still be in service if it wasn't for my liberal application of threadlocker. Even the original machine marks are clearly visible throughout the heat damaged areas of the PP and flywheel. With my eyes closed, my fingernail can't tell what part of the flywheel or PP I'm touching - it feels brand new. Marks and all.
This sort of thing can also happen if the pp or flywheel has been improperly torqued but in this case, with 2.5 experienced dsmers, our short coming was careless application of loctite.

Please ignore the nice contact patch visible on the back side of the pp fingers. That's a whole 'nother story.

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So, the point. The point is that you ought to take care when applying your threadlocker to your flywheel bolts. If you apply incorrectly, or too liberally, you may experience issues ranging from harsh engagement/disengagement to a failure like I experienced.
I recommend applying the threadlocker to the holes in the crank rather than slopping it onto the bolts where it will find a way to squeeze out.

This was kind of convenient, it's even a Mitsubishi!
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Don't be a goon when working on your car.

 

[PieEyedPiper]

Just a quick follow up:

I've been contacted by a couple interested parties that, rightfully, are unsure that I have come to the correct conclusion. Granted, the case made above doesn't exactly show or demonstrate certainty but I'm really not the first guy to have this happen. I promise!
For whatever reason I'm without the shot of the backside of the flywheel - it clearly showed pooling of dried loctite that could easily be felt and seen. This thing was CAKED. I'm quite confident that this was the root cause of the failure.
Though it's pretty tough to call 50k+ miles of good use a failure when considering aftermarket performance clutches.

It's really not a big deal anyhow, it's not like I'm trying to scare kids into skipping out on loctite altogether this is just to get it out there that shit goes down when not paying attention - Be it when applying threadlocker to your bolts or by letting the transmission hang on the disc during installation.

Something else worth mentioning that NHerron brought to my attention was that you could probably rig up a test procedure pretty easily by checking for runout with the flywheel installed dry and then again with the flywheel installed, slathered with loctite.

He also brought to my attention, and it's nice to add for completeness, is that many sources/PDF's indicate that threadlocker does not alter the original torque values of the bolt in question.