"lock tight" on flywheel attach fasteners?
"lock tight" on flywheel attach fasteners?
(OP)
Greetings Gents, a couple questions if you don't mind:
Auto hobbyist here; the Chevrolet Chevelles enthusiasts are discussing loctite red for flywheel and pressure plate fasteners. Of course there are differing opinions. Last time I installed a Chevy flywheel or clutch was 1969, so I don't even remember if the factory used "lock washers"
Also, some of the folks believe that the torque from the crankshaft is transmitted as a shearing force on the fasteners. I doubted that is the whole story, so I thought I'd consult those who know...
Thanks, Jim
Auto hobbyist here; the Chevrolet Chevelles enthusiasts are discussing loctite red for flywheel and pressure plate fasteners. Of course there are differing opinions. Last time I installed a Chevy flywheel or clutch was 1969, so I don't even remember if the factory used "lock washers"
Also, some of the folks believe that the torque from the crankshaft is transmitted as a shearing force on the fasteners. I doubted that is the whole story, so I thought I'd consult those who know...
Thanks, Jim
RE: "lock tight" on flywheel attach fasteners?
RE: "lock tight" on flywheel attach fasteners?
So are French locks.
What's universally used instead is a high- strength bolt with radial grooves in the distal face of the head, which is relatively large and relatively thin. I forget what it's called, but it has a specific name, and is normally self- locking.
I use Loctite(r) on them anyway.
Mike Halloran
Pembroke Pines, FL, USA
RE: "lock tight" on flywheel attach fasteners?
Regards
Pat
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RE: "lock tight" on flywheel attach fasteners?
RE: "lock tight" on flywheel attach fasteners?
As an aside, I once saw a flywheel/crank failure that DID have a locking agent present on a Ford 1800 BDH that the builder had neglected to install the hardened dowel and only used the six retaining bolts. All six (OEM Cosworth) sheared off but, the interface showed NO fretting ! I did find that odd as I would have expected to see at least a little evidence of improper tq or stretching.
I cannot say that the reason the bolts sheared was due to the locking compound, that is a bit of a stretch. I just noted the compound because it was a very difficult to get the little bits out!!!
Rod
RE: "lock tight" on flywheel attach fasteners?
I don't adjust the torque spec for it.
Mike Halloran
Pembroke Pines, FL, USA
RE: "lock tight" on flywheel attach fasteners?
Regards
Pat
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RE: "lock tight" on flywheel attach fasteners?
Chevy small and big block 1960s and 70s - 6 non fitted bolts.
Dodge 440 - 6 non-fitted bolts
426 Hemi - 8 non-fitted bolts
Duramax cutaway engine in the lobby 2004 - looks like a few dozen non-fitted bolts ( probably just 8)
RE: "lock tight" on flywheel attach fasteners?
Flywheel bolts rank near the top of the list. (THE top is inner tie rod threads)
RE: "lock tight" on flywheel attach fasteners?
prevents loose bolts from vibration.
RE: "lock tight" on flywheel attach fasteners?
RE: "lock tight" on flywheel attach fasteners?
Like I said, just the most commonly used in my shop. There are many other types of Locktite brand that are for specific jobs, not all necessary for even racing applications. However, I'm not at all sure about "1000 grades", though.
I use blue in the two compounds because one is a "wicking" sealer for installed parts. Red for most general purpose and green for studs or bearing mounts. Lots of blue and red, very seldom use green as it is difficult to remove.
Rod
RE: "lock tight" on flywheel attach fasteners?
ivymike is correct. The torsional moment transmitted between the crank end and flywheel joint is designed to be taken out purely through friction created by the preload clamping force of your flywheel bolts. This is the only practical way to do it.
Taking the torque through shear in the bolts would require that all of the bolts have an interference fit with their mating holes in both the crank flange and flywheel. If there is any bolt hole clearance, the shear load will only be reacted at two of the bolts (at least until they yield and the other bolts begin to pick up load). And more importantly, any sliding between surfaces at the crank/flywheel interface will quickly result in fretting/galling failures.
Loctite can be an effective form of thread locking if used correctly, and would be perfectly acceptable for locking flywheel bolts. It creates its locking effect by increasing the friction at the thread interfaces. However, Loctite should only be considered as a secondary thread locking device. With threaded fasteners loaded in tension, the primary locking function is the thread friction created by the fastener's installed preload.
A properly designed fastener installation should always ensure that the fastener will not lose its preload, under any conditions such as temperature changes, creep, corrosion or vibration. If the fastener maintains its preload, it will remain locked. The Loctite is just an extra layer of safety.
Regards,
Terry
RE: "lock tight" on flywheel attach fasteners?
thread locker blue 242 medium
and yes & it under stood all bolts must be torqued.
RE: "lock tight" on flywheel attach fasteners?
what is important though, is to take new (non-prestretched) bolt whenever the flyhweel has been taken of the crankshaft.
if using already used bolts, they may become loose and that can result in very nasty accidents. i once saw a flywheel that had come loose and penetrated through the bellhousing into the vehicle interior. that is not what you would like to happen if you are the driver!
RE: "lock tight" on flywheel attach fasteners?
Hmmmm . . . . There was a time, long ago, when we removed and replaced flywheels, many times reinstalling the same one as part of a lower end rebuild, and using the same old bolts over again was SOP. This was especially true for bucks down (just about all) drag racers back when there was no real money being doled out in prizes and corporate sponsors like today were extremely rare.
It never occurred to us (who knew?) that bolt stretch could be an issue. We were concerned with the clutch assembly, mainly disc and pressure plate, staying together. As they say, ignorance is bliss. Sometimes. There were times someone payed dearly for pushing the envelope or being cheap.
RE: "lock tight" on flywheel attach fasteners?
h
Rod
RE: "lock tight" on flywheel attach fasteners?
Really!? Who'd have thought it...
RE: "lock tight" on flywheel attach fasteners?