MSM exhaust Manifold leak thread (in progress) - Miata Turbo Forum - Boost cars, acquire cats.

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Old 05-17-2015, 01:10 AM   #1
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Default MSM exhaust Manifold leak thread (in progress)

OK. so I've owned my new 2005 Mazdaspeed miata about 3 weeks now. I have had one thread about the breakdown of the condition of my car and it can be read here: ( for those who want to see the begining of my issue. obviously its a regular issue for MSM's to have loose manifolds and most well-educated owners tend to tighten thier nuts pretty frequently. anyways, here's my experience so far.

1) a sound occurs at cold-start or even when the car is warm but has setting for 10 minutes or more....
2) the sound is a whispy-cracky...(maybe like a weed-eater) sound...this noise only occurs on throttle...due to high pressure exhaust shooting out of an orfice somewhere
3) after the car has been driven a few seconds...or has come to operating temps, the sound is gone.

turns out its an exhaust manifold leak, either due to a fault in the exhaust manifold gasket or a warp (heat warp) in the mating surface of the exhaust manifold gasket.

a dead giveaway of this issue is this
which is left over by exhaust gases leaking past the seal of the gasket

I have this on my cylinder head as well, and it was right above the runner off # 4

So i ordered an exhaust manifold gasket and dug in to try and fix the problem.

from some prior research, I found that a lot of people tend to break the studs in both the manifold outlet and the head-studs that hold on the manifold. I soaked all of the suds for hours in WD-40 to prevent this as much as possible.

I managed to get every nut loose on all NINE manifold studs working very slow and tapping a crescent wrench (14mm) + the 4 studs on the manifold to turbo inlet (12mm wrench) on each nut with a hammer (light taps)

the nuts on the top and bottom of #4 were very loose.

the studs that connected the manifold to the head all came off except some of the studs(3 of them), backed out of the head as well.

the manifold will not come off. looks like the studs on the turbo inlet themselves either have to be taken out... or the turbo has to be taken off.

by the way don't drop the nuts of the turbo inlet. you'll never find them.

Pretty much where I'm at now is all of the nuts on the manifold studs are off, as well as the nuts on the manifold to turbo inlet. the EGR is loose. so. the manifold wiggles...but I cant pull it off because it only has a little looks like im stuck inbetween a rock and a hard place literally. should I just go Full on and take off the whole turbo or is there a way to get this thing to come off? ...idk well just leave it at that for now.

** this is supposed to be a write up for MSM owners to resolve this issue. still in progress and any advice is welcome.
pictures coming soon
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Old 05-17-2015, 01:13 AM   #2
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Have the flange surfaced and bolt it back up.
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Old 05-17-2015, 01:14 AM   #3
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Exactly what I told him. Also that nut looks like it's been replaced already.
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Old 06-01-2015, 10:33 AM   #4
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Originally Posted by 18psi View Post
Exactly what I told him. Also that nut looks like it's been replaced already.
FWIW that was a shared picture, I never posted the stuff on my car.

anyways I ended up using a stud remover tool to take out the studs from the manifold, also removed the studs from the manifold and turbo that prevent it from being pulled off without removing the turbo.

I went with brand new OEM studs in the head (exhaust manifold studs) and ARP self locking nuts which were a pain to find.

I did not re-use the studs for the ex-manifold -to-turbo junction....I fastened that back with a 10.9 JIS flange head set of bolts and high temp thread locker...some may think that is a no no, but it allows the manifold to be pulled without dropping the turbo in the future...god forbid.

good info....the gasket for the turbo inlet is the same one that comes in a felpro set for a mazda 323 can order one at your local auto-zone (Part # ES70511) for 30$....I had also bought a mazda OEM replacement that was 78$....they were the exact same thing.


The job has since been a success, no leaks, sounds or anything of that matter. the next day I changed the diff oil, the trans oil, and the engine oil and then went with some of the NGK extended reach #6 plugs that FM likes and we drove the car all the way down to Jacksonville Florida and back (~ 860 miles)

Also down in Florida I installed a FM intake kit that I found for 100$...I went with a cheap spectre filter....It did fine on the 360 mile trip back and sounds amazing...I wasn't expecting the cool noise from the recirc valve

I actually have not installed the turbosmart MBC... It will actually hit 10psi if I push it. my boost gauge will throw a red flash of light at 10 PSI If I go there. which is kind of odd because I've never seen it do that. but I guess some how its wired to give me a warning? or it can somehow tell me when the ECU issued a boost cut? IDK
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