Loctite on main bearing bolts

[2speed]

Yeah or nay on loctite on the main bearing bolts on a Burtz block? Blue loctite that is....

[Keith True]

Ask Mr.Burtz.That way it comes from the source,and not a dozen guys telling their opinions and how their grandaddies did it for years.

[J Franklin]

I use Loctite on every bolt & nut even when using lock washers with the exception of head bolts that need re-torquing.

[nkaminar]

Ask Terry.

[Terry Burtz, Calif]

Blue (Medium strength) Loctite applied to clean threads is a good choice.

The threads on the head studs that screw into the cylinder block should have anti-seize, and the head nuts should have nothing on them.

[rotorwrench]

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Stuff that is made for high torque applications generally don't use or need a thread locking compound. Smaller fasteners that are subject to higher vibration levels with no other locking feature should have exactly what Terry mentioned.

This has nothing to do with the model As but it is food for thought. Helicopters are currently required to have two locking features on all control system linkage hardware. Many use a locking castle nut with a cotter pin and some use a locking nut with safety wire. The Robinson types used steel locking nuts with a pall nut. That always reminds me of my late Mercury 8CM flatheads V8s that used a pall nut on the connecting rod nuts. They likely didn't need them but I always put them back on there during an overhaul.

[ThirstyThirty]

NAY!

I never use loctite on any rod bolt or (especially) main bearing main cap!! no exceptions!

[ThirstyThirty]

Originally Posted by rotorwrench

Stuff that is made for high torque applications generally don't use or need a thread locking compound. Smaller fasteners that are subject to higher vibration levels with no other locking feature should have exactly what Terry mentioned.

This has nothing to do with the model As but it is food for thought. Helicopters are currently required to have two locking features on all control system linkage hardware. Many use a locking castle nut with a cotter pin and some use a locking nut with safety wire. The Robinson types used steel locking nuts with a pall nut. That always reminds me of my late Mercury 8CM flatheads V8s that used a pall nut on the connecting rod bolts. They likely didn't need them but I always put them back on there during an overhaul.

interesting! "two locking features"

[dave in australia]

Originally Posted by rotorwrench

This has nothing to do with the model As but it is food for thought. Helicopters are currently required to have two locking features on all control system linkage hardware. Many use a locking castle nut with a cotter pin and some use a locking nut with safety wire. The Robinson types used steel locking nuts with a pall nut. That always reminds me of my late Mercury 8CM flatheads V8s that used a pall nut on the connecting rod bolts. They likely didn't need them but I always put them back on there during an overhaul.

On Kingairs, the trim tab actuator have four levels of locking, and two actuator rods connecting the trim tab. A double clevis, with one inside the other that is made offset by a locknut pushing the outer clevis only. The clevis bolt can't be removed without twisting the actuator rod to get the head past the other bolt head, they are inserted with heads towards each other and nuts away from the centre of the control. Then a nyloc castle nut with a spilt pin. This was also checked by two licensed airframe technicians.

[katy]

Sounds like a belt and suspenders situation.

[ThirstyThirty]

Originally Posted by katy

Sounds like a belt and suspenders situation.

[rotorwrench]

If you have no bum to speak of, it takes what ever it takes to keep your pants up. I state from experience.

[2speed]

Originally Posted by ThirstyThirty

NAY!

I never use loctite on any rod bolt or (especially) main bearing main cap!! no exceptions!

Why?

[ThirstyThirty]

Originally Posted by 2speed

Why?

Thanks for asking...

as a mechanical fastener locking enhancer... can it hurt? Loctite Blue? probably not.

but, no need for any thread locker on engine rod bolts or main cap bolts. they are designed to stay put... with torque setting loads as designed! and they will and do!

hope this helps. to me, my comment is beyond just an opinion.

[ThirstyThirty]

furthermore... from minds bit smarter than mine.... AI:

AI Overview

No, Loctite blue is generally not recommended for engine main cap fasteners. Main cap fasteners are designed to be torqued to a specific value to ensure proper clamping force and bearing support. Applying threadlocker like blue Loctite can interfere with the intended clamping action and potentially lead to issues like bearing damage or fastener loosening.

[rotorwrench]

Anything that remains in liquid state when applying torque to a high torque fastener will increase the bind on the threads at the proper torque as a thread lube would do. Some fasteners can't use any form of thread lube or it will damage (stretch) the threads. I always go by the manufacturer's recommendations. Terry is that so go by his recommendations on his product.

[ThirstyThirty]

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