Alternatives to Flywheel Safety Wire

J

jeepguy1948

Well-known member
I really dislike using safety wire on the flywheel bolts. This is probably because i can never feel satisfied with my work. I don't see why internal star washers and/or Locktite wouldn't work (that I can think of). I would like to hear other's thoughts. To those of you that want to tell me "it worked fine for more than 90 years why change?" All I can say is "because I want to" and " other options worked on other cars for more than 100 years so why not on a model A?"
 
I race these things, and never use the stock bolts, or wire, if a bolt is tight, it will stay tight. For years I used the tin plate and flathead V8 bolts, no problems. On my last engine I used ARP bolts. I also never use Loctite, just oil the threads and torque to 65 lbs.

This is a problem area for performance 4-bangers, so I drill and tap for 2 extra bolts, I've even hard chromed the crank to achieve a tighter fit between the wheel and crank.
 
I race these things, and never use the stock bolts, or wire, if a bolt is tight, it will stay tight. For years I used the tin plate and flathead V8 bolts, no problems. On my last engine I used ARP bolts. I also never use Loctite, just oil the threads and torque to 65 lbs.

This is a problem area for performance 4-bangers, so I drill and tap for 2 extra bolts, I've even hard chromed the crank to achieve a tighter fit between the wheel and crank.
 
I bought grade 8 bolts from McMaster Carr. I little longer than stock because I have a Burtz crank. I tried the split ring lock washer but the bolt stuck out too far and interfered with the clutch disk so I went to tight with loctite.
 
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The stock safety wire as came from the factory was not much better than nothing.
Safety wiring was in it's infancy in those days.
There are many videos on Youtube on proper safety wiring procedures. Torquing a bolt to proper spec and using safety wire, it will not come loose if design ultimate load in not exceeded.
On flywheel bolts, lock washers will fail. Too much torsional vibration.
It has to do with the laws of physics.
 
The stock safety wire as came from the factory was not much better than nothing.
Safety wiring was in it's infancy in those days.
There are many videos on Youtube on proper safety wiring procedures. Torquing a bolt to proper spec and using safety wire, it will not come loose if design ultimate load in not exceeded.
On flywheel bolts, lock washers will fail. Too much torsional vibration.
It has to do with the laws of physics.
 
I use ARP flywheel bolts and red Loctite, torque to 65 ft/lbs.

Been doing it for years with no problems.

Chris W.
 
I use ARP flywheel bolts and red Loctite, torque to 65 ft/lbs.

Been doing it for years with no problems.

Chris W.
 
'28 RPU said:
I really dislike using safety wire on the flywheel bolts. This is probably because i can never feel satisfied with my work. I don't see why internal star washers and/or Locktite wouldn't work (that I can think of). I would like to hear other's thoughts. To those of you that want to tell me "it worked fine for more than 90 years why change?" All I can say is "because I want to" and " other options worked on other cars for more than 100 years so why not on a model A?"
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Is this a stock application with a stock flywheel weight, or something different? We know it’s worked for 90 years, and why change, right. But you didn’t describe what you’ve changed that requires the change.

What are you doing to necessitate the re-evaluation?
 
Torque them and wire them, it's pretty easy to access, simple, quick, and works.
 

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I safety wire the flywheel just like I safety wire an aircraft propellor.
 

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If you are running a stock configuration or near stock, the original bolts are good.
If doing something a little more demanding, be careful of the GR8 bolt options.
I just had an application here with aluminum flywheel and 6 GR8 bolts, the bolts had yielded either from too much torque in application or the torsional vibration.

Be realistic about your application and then buy the proper hardware.

John
 
i have wondered about safety wire. and as well cotter pins.
maybe it is not so much stopping the bolts or nuts from coming loose as it is to capture them and preventing one from backing off and falling into or binding with somewhere that it will cause even more damage.
good fasteners properly torqued usually stay in place.
i still wire and cotter pin if the application was designed for it.
 
G Pierce has the right method. Safety wire should be tight. It helps to have safety wire pliers that wind the wire when the knob is pulled.
 
Star locks leave their mark on any steel part they are used on. They are thin enough but too aggressive on metal erosion. If another washer is used then the head stands too proud. After a 40+ year career in aviation. It's just habit to keep .040", .032". and .020" annealed stainless safety wire around. Ford likely used what would be considered bailing wire by most farmers. It's just annealed black steel wire.

Cranks in later V8 cars don't use safety wire. They just don't have a history of coming loose if properly torqued.
 
One other thing that folks need to consider is the flywheel bolts in essence are just clamping the flywheel to the crankshaft. It is the two dowels that are doing the work. There really should not be any forces pulling or pushing the flywheel off of the dowels in the fore/aft direction. Owning a set of Safety Wire Pliers is a good 'crutch' if your skill set is lacking when wiring a drilled bolt head, but in my view, it is more about torqueing the fastener to a flywheel that has properly fitting dowels and a clean mating surface. If the fastener has the prescribed stretch on the threads, when the safety wire is installed correctly, it should not allow the fastener to loosen.
 
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