Mystery Nut--Anyone Identify?

Mystery photo. How are we to tell?

Elle wrote:

Can you identify the nut who took this terrible picture? As blurry as this photograph is, it's most likely to remain a mystery, though I'd venture a wild guess at a nylon-self-locking nut.

Did you shear this nut off yourself or just find it? Are you sure it's not really a old metal tire valve stem cap?

nb

You didn't say what model Honda you have. But it looks like a manifold nut to me. On my '00 Accord both the intake and exhaust are 12mm.

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I think it's an out-of-focus picture of one of them alien space craft that they used to publish back in the 70's. Looks a bit taller though :-(

Tip: On digital cameras that don't have a MACRO or close-up setting, you can hold a magnifying glass or Grandpa's reading glasses in front of the lens, and it works just fine.

'Curly'

Beg pardon. It's a 91 Honda Civic. Nasty, thanks for the suggestion. My Chilton's does indeed show a bunch of exhaust and intake manifold nuts that seem to fit the bill. Majestic's online parts site confirms that the exhaust manifold has nine self-locking nuts. It's also certainly rusted enough that I would expect it to be either in a weather path or on the exhaust system somewhere. I'll take the shroud off tomorrow and confirm. Thank you!

Curly, good tip. I know it's a lousy photo.

RWM, it's some kind of self-locking nut and so is a little unique looking. I thought someone might recognize it before, ya know, I discover the hard way and my engine falls apart or something on the highway later today.

"Nasty" wrote

It looks like a standard flanged nut with some sort of a PAL nut as locking insurance.

JT

Elle wrote:

snip

That quite a tip Curly... Who would have known???

I'll pass that onn to my cheap friends who have cheap cameras!

JT

(Yep, you can learn something new every day)

That would be TeGGeR... oh wait, wrong picture ;)

Do you have a pic that's not quite so fuzzy?

Ha. We're all gearheads in this together. :-)

I'm afraid not. I am looking for a magnifying glass. Little busy today.

Matt Ion wrote in news:rXIag.172150$WI1.82189@pd7tw2no:

Whaaaat? I resemble that remark. >:^Þ

It's an exhaust manifold nut. Looks like part of the stud is still in it too, so that's broken.

Remove the front heat shield for the exhaust manifold and have a look at all the studs.

I also thought it looked like an exhaust manifold nut. The question remains though, how did it get under the dash? Was Elle under the dash recently and unknowingly transferred the nut there?

Eric

i would put money on it being a stud/nut for the exhaust system. either the a/b/c pipes, the catalyst, or possibly the exhaust manifold. its got the same patina of a nut/stud thats been in high heat all its life.

nuts from the front suspension. There are 4 identical sized nuts (all

No; miscommunication. My Civic was on ramps, and I was under the car, grinding out one of the control arm bolts, for a long time (see other thread). About mid-day I moved the cardboard and wood planks on which I lie for this sort of work and found this lock-nut (with, as Tegger said, part of a stud attached). I figured the grinding vibrations knocked it free.

I'll get a closer look tomorrow. Car's driving okay, all things considered (especially all my monkeying with everything).

Thanks, folks, this will save me a lot of time.

wrote

Is that 12 mm the nominal diamter of the suspension bolts onto which these suspension self-locking nuts fit, though? That sounds more likely.

The 12 mm I mention for this mystery nut is the nut head measurement. That is, a 12 mm socket fits it. The nominal diameter of its corresponding stud appears to be 6 mm or 8 mm. (The stud diameter is a little hard to measure while it's stuck in the nut.)

Thanks for the input. I'll update tomorrow, hopefully.

Most 12 mm nuts on a Honda are threaded for an 8 x 1.25 mm bolt.

Eric

Hello: I just checked the stud/nut diameters with a caliper after your and Elle's posts. Yes, you two are correct: the 12x1.25 mm that Honda manual refers to is the stud diameter and not the nut diameter (should have remembered this...my apologies). For the 12 mm diameter nut Elle refers to, looks like the corresponding stud size is 8 mmx1.25 mm as Eric correctly suggests. If yours came from the front suspension, there is just one such self-locking-nut according to the front suspension diagram; 8x1.25 mm, stabilizer bar /lower arm attachment. According to the diagram, in the front suspension, there are

That's what it looks like to me - a high-temperature locking nut.

Mike

I took the exhaust manifold shroud off today. It is indeed an exhaust manifold nut (with broken-off stud stuck in it). It's the one nearest the distributor.

I am amazed at how many people (Nasty, Tegger, Eric, SoCalMike) nailed this, and with a fuzzy photo, too. What a phenomenal newsgroup!

I see the stud on sale at Majestic online for a couple bucks.

I reckon I'll see how my ball joint castle nut/stud work goes today and then make a trip to the junkyard. I think the front desk man and I could become an item... :-)

Much obliged for everyone's input. This all is valued work to me, and I couldn't do it nearly as efficiently (and at some points, not at all) without the extensive experience of so many of you.