The Creeping Downpipe

[velocity2878]

So…I’ve had issues since week 1 with my downpipe creeping.

1. The original lock washers that came with the FM2 kit fell apart as we were installing and FM wanted to charge me $5 a piece plus shipping (awesome customer appreciation after spending so much money with them).
2. We tried other lock washers and it crept
3. We tried double nuts and crept
4. We made a custom copper gasket and re-applied the double nuts and it continues to creep

I want those gasses passing through my exhaust and not into the cabin and I don’t want to hear that turbo tick anymore.

Does anyone know what I can do to tighten that pipe up for good?

[wonton]

pull the dp off and go get the flange of it flatted, it may be warped!

[velocity2878]

That's not a bad idea - thanks

[wonton]

yeah man! while your at it you can pull the turbo off at the same time and have them mill that surface as well!

[velocity2878]

I was thinking the same thing :)

[RotorNutFD3S]

And don't use gaskets between the turbo and downpipe, or the manifold and turbo for that matter, they don't help matters on our cars. After getting everything flat again, may be wise to restud the turbo (for peace of mind and since you have messed with them quite a bit now), and then use self-locking nuts and flat washers. That's what held my downpipe on and never had an issue with it.

In the following image, you'll want the ones that either look like the first two on the top row or the 4th from the left on the bottom row:

http://imghost.indiamart.com/data/D/K/MY-944030/lock-nuts_10798518_250x250.jpg

[carfiend]

A properly torqued nut should not require a lock washer. Most applications don't require them and some studies show they should never be used.

[velocity2878]

Noted - thanks guys!

[RotorNutFD3S]

Sounds like the OP is referring to the nord-lock washers, not the typical lock washer.

[carfiend]

Yeah I guess I should specify. I'm refering to split lock washers. They look like a little one turn helical spring.

http://www.engineersedge.com/split_lock_washer.htm

[RotorNutFD3S]

Yep, and you pointed out good reasons that they should not be used. Another good one to keep in mind is the typical lock washer will be flattened permanently by the heat produced by the turbo, so it won't even be able to do it's job.

[quadmasta]

Stage 8 fasteners will solve this problem permanently....unless the studs back out of the turbo.

[ben91]

I think Sean's right, sounds more like a flange that is out of flat than a problem with hardware. The turbo to downpipe junction typically is not the problematic one in a miata; it's the turbo to manifold junction that likes to stretch hardware.

I don't know where you live, but there are a couple of Fastenal stores around town.

[Doppelgänger]

Use copper locking nuts. I have the same setup and have never had a problem with using them.

What do you mean that the washers "fell apart"? How would that prevent you from using them?

[velocity2878]

they looked like two little flat gears on top of eachother and it just fell apart...i dunno. Copper nuts are a good idea, but I'll pull it off as well to make sure it's flat.

[RotorNutFD3S]

Like this?

http://www.billswebspace.com/Nordlock1.jpg

That shows how they are supposed to look.

[Doppelgänger]

Yeah, they're 2-piece by design. They're not broken. Install them and remember to install them with the large notches facing eachother like the picture posted above. I'd still recommend using copper lock nuts on top of those washers.

[velocity2878]

yup - that's them...you guys are good!

[velocity2878]

...or maybe I'm just really bad :o

[iscariot]

I've got some of those washers kicking around somewhere, along with stage8 hardware - bought them before i realized that begi went to m10x1.5 instead of m8. LMK and I'll think of a price.