So, finally getting around to putting the TCM IO-360 back together.
Brand new cylinders, through bolts, nuts... the works.
Bought good ATS cylinder base wrenches. You know, the "thin-wall construction guarantees they will fit nuts close to the cylinder casing without grinding down the wrench's outer diameter."

Yeah.

The new cylinders have a raised ring around their base for some unknown reason where the old ones didn't.



Had to grind the wrench down a LOT to fit over the nut. Of course, it broke 1/2 way through the final torquing sequence.
While grinding on the belt sander, I was careful to not over heat the tool (warm to touch) to not damage the temper.

I Welded the wrench but that just made things worse.


Any ideas? I ordered a new ATS wrench but I'd need to remove nearly 50% of the material - risking a second breakage.
Is there a better wrench with thinner walls? Snap-On maybe?

I double checked with Continental and I did buy the right nuts for this motor. The old ones were superseded but they didn't change them to 12 point.

Looks like you might be able to get it in if you just sand down the outside edge rather than the whole thing? This would give you considerable more strength. But that really does suck. I haven't managed to break my ground down ones yet. They are black but I dont remember the brand.

I thought about radius-ing the top of the wrench like you said.
I think I'm a little gun shy after the first one failed.

The first time, I just put it on the belt sander until it fit. Probably took off a lot more than I needed.

You're probably right tho. carefully take off the top corner until it just fits the bolt.

Broken base nut wrenches dont make very good garage wall art.

I use crowfoot wrenches and lots of fanangling with various extensions to get the base nuts snug, then the torquing with ground down ATS wrenches. By doing just the final torquing the wrenches last longer, but they still inevitably break every couple years.

Making matters worse, Continental can't seem to make a consistent nut.


I was able to carefully grind top and sides to fit without removing material from the bottom half but not this one.

That nut should have never made it out of the Chinese factory TCM buys nuts from

CenterHillAg wrote:I use crowfoot wrenches and lots of fanangling with various extensions to get the base nuts snug, then the torquing with ground down ATS wrenches. By doing just the final torquing the wrenches last longer, but they still inevitably break every couple years.

There's an open end cylinder base nut wrench available, if I recall. I helped my A&P IA friend assemble the top end on his 470 a few years ago just for the experience, and that's what we used.

Edit: I remembered wrong. So maybe try the crow's foot method.

There is a semi open wrench for radials.

Bagarre wrote:Making matters worse, Continental can't seem to make a consistent nut.


I was able to carefully grind top and sides to fit without removing material from the bottom half but not this one.

That nut should have never made it out of the Chinese factory TCM buys nuts from

Wow, what is that??

I used the cylinder wrenches for the light torques and never had an issue getting crow feet in to finish torquing (after calculating the modified settings for the crow feet...it made a difference).

I wonder what that raised ring is all about.

Since I’m only working on my engine and don’t plan to remove cylinders very often I bought the cheapest cylinder wrenches I found on Spruce (maybe it was amazon?) and ground them to fit.

Bagarre wrote:Making matters worse, Continental can't seem to make a consistent nut.


I was able to carefully grind top and sides to fit without removing material from the bottom half but not this one.

That nut should have never made it out of the Chinese factory TCM buys nuts from

Brutal. I had a B nut from Spruce with no threads in it the other day. Crazy how some of this stuff gets through...

As an A&P IA I would not install that nut in the photo on an engine even if it did come from TCM. Remember that the installing mechanic is the last point of quality control. There have been failures of nuts in various applications do to splitting and that thin side would have reduced strength.

Tim

bat443 wrote:As an A&P IA I would not install that nut in the photo on an engine even if it did come from TCM. Remember that the installing mechanic is the last point of quality control. There have been failures of nuts in various applications do to splitting and that thin side would have reduced strength.

Tim

Completely agree 100%. Already ordered a new nut and re-checked each of the others.

A cylinder through bolt nut is a really bad nut to have fail due to defect.

I plan to give Continental a call about it as well.

I was pretty sure it was your plan to replace it as you seem to be a "detail" kind of guy. I just wanted to point it out to others with less experience who may read this thread in the future that it requires replacement.

Tim

They just depend on the A&P as the final quality assurance person to keep that crap out of the fleet.

Try the Spruce wrench David. They're black and I have mine ground down super skinny and they are still holding. Maybe I'm just lucky...if it helps to send you my wrench, let me know.

Anything to get that hot rod of yours closer to flying!

Aryana wrote:They just depend on the A&P as the final quality assurance person to keep that crap out of the fleet.

At $7 a nut, it should have never made it to the fleet looking like that.

Aryana wrote:Try the Spruce wrench David. They're black and I have mine ground down super skinny and they are still holding. Maybe I'm just lucky...if it helps to send you my wrench, let me know.

Anything to get that hot rod of yours closer to flying!

Thanks. I was able to get the second wrench to work by thinning the upper edge to slip past that bump on the cylinders without removing material from the bottom. So, case and cylinders are torqued at this point. Will replace the wonky nut when the new one comes in.

cheers.

Great job, more little victories for you on this beast. [emoji1360]

$7 a nut...for shame!!! SHAME!!! That nut wouldn't be fit for my car much less any aircraft...just based on cosmetics alone. [emoji6]

That nut should have never made it out of the Chinese factory TCM buys nuts from [/quote]
Another instance showing China’s lack of quality control....which is saying we don’t have any respect for the end user.

Well the FAA exonerates suppliers from the final liability by making it the responsibility of the installer to ensure that the part is actually airworthy and confirms to its specification.

I'd consider the QC issue to be TCM.

I also wouldn't chalk it up to quality issues from China. I buy pallets of hardware from both domestic and Chinese sources for my production.

The US hardware is roughly as bad for features (threading, head conformance, etc). China is arguably worse for material specs (hardness/temper and finish).

The difference is that I can call the Chinese factory on WeChat and get resolution in minutes, and replacements in days fresh off the factory floor on good terms. In the US, they might lose the complaint, make me send them hardware so they can see for themselves (my pics and hardness testers aren't good enough, apparently), take two weeks off in the middle and not allow anyone else to take care of the problem, or simply punt and tell me finally after 4-5 weeks they can't do better, use someone else if I want a quality product, and quit taking calls. Tens of thousands of dollars on the line, especially for graded hardware.

So in general, I prefer my Chinese mills over the lazy American ones. Most of the mills in the US are a wasted phone call. Good parts are hard to find, and I'm loyal to the handful that seem to still want to sell to quality businesses outside of the captive "buy American" mandates for the defense industry. It's been pretty sad to see things deteriorate like this domsstically. So I've taken their own advice and my hardware ships from China in most cases now, except some hardened stuff from a trusted source here.

As an end manufacturer, my company is where the buck stops for things like nuts and bolts in terms of QC for anything leaving the shipping area. If I get a lot of junk, I find another supplier.