Safety wiring bolt heads, Do's and Don'ts...

[Erik the Awful]

Good safety wiring is an art. Turbine engines require safety wire, and I got plenty of practice on air start carts. Still, I'm nowhere near as good as hydraulics technicians. They have to safety wire aircraft components in places where you can't even fit the pliers. They know tricks I still haven't seen. I taught airmen how to safety wire, and the only thing that sucks worse than having your supervisor cut your safety wiring and telling you to start over is being that supervisor and having to listen to the whining and "What was wrong with it?" complaints.

The safety wire needs to hug the bolts as it wraps around it. It needs to be routed so that the tension holds the wrapping strand down, and doesn't let it flop up over the bolts. It can't be too tight. It can't be too loose. The end must be snipped less than an inch long and folded under. You have to use the correct type and size of wire.

Our E36 BMW that we race lost the CV axle bolts at a race. We grabbed some loctite and reinstalled the bolts. Before the end of the race they came out again. I don't know why, but BMW CV axle bolts hold just fine until you hit the track. They'll be good for a few races, and then they'll just start jumping out of the flange. I told our team captain to crossdrill the bolts and I'd safety wire them. Boom! No more problems with the bolts. Last December we went racing at Road Atlanta, and another BMW team was having the same problem. They loctited the bolts and sure enough, they came out again. We told them to safety wire them and as far as I know they stopped having problems.

Our last race we had a CV boot rip, so we pulled the axle and tried (unsuccessfully) to reboot it. When I went to reinstall the axle I realized we didn't have any safety wire. I used some generic wire another team had, and it was a royal pain getting it to wire without breaking when twisting. I did get it together, but we knew it was a temporary fix. Use the correct wire!

The pro pliers are easier to use, but Harbor Freight's pliers work well enough for a hobbyist.

The trick to wiring those crazy multiple-bolt fixtures is to measure the length from the start to finish, and get about half again that length in wire. It's cheap so you don't worry about how much excess you're going to have, except that you have to work around the tails until it's done. There are some cheats when it comes to twisting it, but the more critical the wiring, the less cheating you can do. Theres' also a trick on the final wire tightening on each bolt to get the wire snug, but you'd really have to see it to understand.

 

[Schurkey]

Try to use Loctite on a aircraft propeller or almost anyplace on a aircraft.
After working on aircraft so long i can't hardly bring myself to use Loctite as none of it seems to do a satisfactory job, but it is better than nothing.

The "secret" to thread lockers such as "Loctite" is that they need the absence of air (anaerobic) AND the presence of "active metal". Lotsa folks know about the anaerobic part, but don't know about the active metal part.

Steel, stainless steel, brass, and some other metals are "active" to varying degrees. Aluminum is not. Certain platings on bolts/nuts are not. Which means, for many applications, you really do need to spray the parts with the Loctite "Primer/Activator" stuff, or the threadlocker will never properly "set". Using the Primer/Activator isn't always needed...but it doesn't hurt.

www.amazon.com/gp/product/B0002KKTSG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

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[Spareparts]

I get it. big circle to tighten at the bolt!

 

[Road Trip]

The engineers at my company specify 6/8 twists per inch.

...And of course, following your engineer's written guidance is the
only way to go. As I used to explain to the young airmen
fresh from Tech School & going through the OJT process on
the flightline, *IF* you follow the T.O. exactly...then it becomes
your ironclad insurance policy if the unthinkable happens & the USAF
Mishap Investigation Process is deployed. (!)

By doing so, if the root cause is determined to be something
you were erroneously told to do by the T.O., and you
followed it to the letter, then the recommendation/focus will
be solely on correcting the T.O., not you.

So, when their next question inevitably was, "What do I do when I
know that the T.O. is either wrong and/or there's considerable
room for improvement? Just follow it blindly?" (NOTE: I
remember coming back from Tech School pretty convinced
*I* was the Subject Matter Expert in my field of endeavor...
so I actually understood where they were coming from, and
didn't take offense. :0)

Without hesitation, I would immediately drag them back to the
shop's T.O. library & show them this:

EDIT 18-Jul-2023: Cropped internet address from following
screen snap -- not necessary to convey concept of how we
used to fix the books we fixed with. (Note: No system
capability has been divulged.)

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They got it. Instead of laboring as a helpless victim, being held down by the T.O.
while working on aircraft, and filling up the shop's bandwidth with complaining...
instead my expectation was that they were to cheerfully embrace the T.O. as
their personal insurance policy. And if the T.O. was the LIMFAC (LIMiting FACtor)
in the repair process, stop & take the time & use the documented process to
make it better!

Q: Can I take credit for this approach?

A: Yes & No. No, because this wasn't my idea...this was simply the way that
the elders taught me when I returned from Keesler AFB all full of myself back
in '78.

And Yes, because when I found myself at the far side of my career I remembered
the elders' guidance & I passed it on to the young airmen who were gearing
up to replace me. (And yes, mentoring the next generation of flightline
troubleshooters was one of the highlights of my career. :0)

****

So yeah, I didn't mean to infer that the number of twists-per-inch that I had to
follow was a superior number to what you had to follow per your engineer's
specification. Instead, we're on common ground, in that we were both taught
to follow the written specification exactly...and we did, which is how we got
away with working on machinery that rewarded a methodical approach &
attention to detail, and punished pretty much everything else.

Cheers --

 

[Road Trip]

I've never, ever used genuine real-true safety wire on a fastener. Read about it. Imagined it. Never actually practiced it. The Bus Company wanted us to "safety wire" the bolts used on driveshaft flanges at the transmission output flange. What they specified was totally insane. The Grade 8 bolts had been drilled in-house, through the THREADED SECTION not the heads. Then we put nyloc nuts up the threads past the hole in the bolt, and torqued, so that the nylon insert was shredded by the jagged ends of the holes stupidly drilled through the threads. Then they gave us non-hardened, non-Stainless plain ol' dirt-cheap "Mechanic's Wire" to loop through the holes drilled into two bolts, without ever going through the nuts. We twisted the two strands of wire linking two bolts, from the middle with an awl or Allen wrench, or whatever we could find. It was worse than merely stupid and wasteful, it was actually counterproductive due to the damage done to the nylon insert in the nut.

But that's what our moron "engineers" wanted, and they had the college degrees, not me. So we all did what we were told, for years and years.

Ugh. I feel your pain. As a weekend warrior (pre 9/11) I was being trained
by no-nonsense craftsmen who held themselves to the highest possible
standard of workmanship. I enjoyed being part of the process...and at
the same time humbled by the skills on display.

...and then after drill weekend I'd return to the civilian world, where it
seemed that so many folks were putting more effort into 'avoiding
work while looking busy' than it would have been just to square up to
the task and git 'r done! :0)

The engineers you describe in your tale of woe sound like the kind of
guys that would have directed you to drill holes into the bottom of the boat
in order to let the water out:

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It sounds like you have managed to graduate from that work
environment. Congratulations on surviving that nonsense.

Cheers --

 

[Road Trip]

Ford Cammer 427 on factory dyno undergoing max output reliability testing

Reflecting upon this previous post, I may have inadvertently breached
the unspoken bowtie protocol by sharing a SOHC 427 F**d photo
on the GMT400 website?

Problem is, photos of a BBC at full chat on a dyno w/glowing headers seem
to be as scarce as hen's teeth on the internet?

****

Well, I decided that I should attempt to make amends with my new friends,
so I scoured the internet, and finally came up with a twin-turbo 632ci BBC
that purportedly makes in the neighborhood of 2500hp.

The good news is that the headers on this engine have both a good glow on
+ the area adjacent to the cylinder heads are *not* glowing. It seems that
the laws of thermodynamics transcends which brand the powerplant is:

Twin turbo Big Block Chevy on dyno making a purported 2500hp

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This now adds a 3rd data point to the theory that keeping the header flange secured to the cylinder
head creates a heat sink to the water jacket allowing the header gaskets to remain cool & leak free.

NOTE: Back when I was being dogged by blown header gaskets they hadn't yet put the copper jobs
on the market. Today, a set of soft copper gaskets backed up by safety-wired header bolts would be my
personal recommendation. (That along with the thickest header flanges I could find.)

 

[Schurkey]

Oh, great. Now I'm walking around with a limp, and if it doesn't go away in four hours I gotta go see a doctor.

 

[RichLo]

After reading that post then seeing the pic, I had to re-read to make sure it was a google pic, lol. Lots more questions if that was his way of showing a project vehicle engine.

 

[Road Trip]

After reading that post then seeing the pic, I had to re-read to make sure it was a google pic, lol. Lots more questions if that was his way of showing a project vehicle engine.

Try as we might, up 'til now we've enjoyed only moderate engine
building success with a purely empirical approach, relying mostly
on the old school 'monkey see, monkey do' methodology enhanced
with a handful of freestyle 'by guess & by gosh' optimizations. :0)

I spent a career fixing other people's stuff on their timetable
during the day, and then at night reading everything I could find by
authors like Jenkins, Yunick, Vizard, Kaase, Lingenfelter, and The Old One.
(aka: Larry Widmer) I watch engine dyno videos like Rainman watches
Judge Wapner -- especially the Engine Masters stuff.

Why am I sharing this? Well, over the years I've developed a burning
desire to up my game & get serious about quantifying my efforts
to improve the volumetric efficiency of whatever is being put together.
And after years of looking for something I could swing, I finally found
a previously enjoyed Superflow 600 flowbench for sale that I couldn't
pass up -- it was literally a once in a lifetime opportunity:

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Note: PO on the right, yours truly on the left with my trademark sheet-eating grin that I save for moments like buying other people's 'obsolete' test gear. :0)

Anyway, I'm normally hesitant to open the kimono in public & let others see
exactly what kind of misguided shenanigans we're up to. But as I've admitted
to elsewhere, I enjoy a good sleeper, and we've got a couple of projects where
we're hoping to bring some underhood heroics to some sleepy looking stuff.

...and despite my mantra of that it's just a chore truck, in the interest of science
I would be downright giddy to see how much real-world torque can be extracted
from a 496ci version of the L29 with ported heads, the right roller cam, beehive
valve springs, blah blah blah. Of course, with my current financial trajectory this
may never happen...but if I were to be graced with a winning lottery ticket, I hope
to make the GMT400 community very proud on an expedited basis. :0)

PS: RichLo, I hope to someday put up my very own glowing header 'BTU-ty shot'
instead of just sharing someone else's hard working art. And be on the lookout
for the safety wire...then you can be sure that it's mine. Remember, you heard
it here first!

Cheers --

 

[454cid]

Good safety wiring is an art. Turbine engines require safety wire, and I got plenty of practice on air start carts.

For the Blackbird?