What a debacle. The turbo exhaust side to downpipe gasket started leaking and filling my cabin with exhaust fumes when the HVAC was on a few months back. First it was subtle then it was so bad I couldnt use the HVAC at all. I put my nose to the heat shield while my girl hit the gas pedal and the source was obvious.

This leak was my fault because I reused the bolts and studs when I dropped the downpipe/cat a few months ago when changing out the oil cooler gaskets.

So, I order 3 new studs, 3 new bolts, a new gasket so I can do this the right way this time. Well, the the top stud (THANKFULLY and not the bottom studs) totally strips out inside the turbo manifold. Why? I have no idea. I never removed it before. Maybe a Mini mechanic cross threaded it. It took forever to pull that SOB out. I finally had to heat it with MAPP gas and take a vice grip to it.



After I finally get it out I go to chase the threads with a 8mm 1.25 tap. The FRIGGIN TAP CRACKS INSIDE THE MANIFOLD flange. Taps are sharp as hell, but brittle.









I spend the next buncha hours trying to counter rotate the broken tap with some nail punches and pliers, then MAPP gas to loosen and maybe break the brittle tap...to no avail. Drilling through the tap is impossible. Its too hard to drill through. Screw extractors are worthless as well.

I finally decide to destroy the threads in order to get the tap out. So I drill around the periphery of the tap, break numerous drill bits in the process, and use a punch to rotate the tap into sections of drilled out threads and push the tap free. Note, a normal drill barely fits in the space. A mechanics's right angle drill and some stubby drill bits would have sped things up.

GREAT. Now I have an oversized hole with chewed up thread sections meaning I cannot use the new stud. So I decide to use a through bolt and nut. I ream out both holes (manifold and downpipe) enough to get a longer 8mm x 1.25 bolt clear through and use a OEM stud bolt on the turbo side.

Fine. A problem remains. The turbo causes a curvature in the manifold right after the hole/flange of the manifold. This doesn't allow a bolt to fit against the flange. So I shave the OEM bolt down on one side so it will sit flush against the manifold rather than at an angle. I torque and it holds. Two other bolts I tried before that broke because they weren't automotive grade.

I forgot to take a pic of the finished product... sorry. Will post next time I have the shield off and can snap a pic.

I hope it holds but am not confident. I used a lock washer on the bolt head and the OEM aluminum bolt and some red/high strength thread locker on the OEM bolt threads. Problem is aluminum and steel dont play nice together and threadlocker doesnt survive exhaust manifold temps. I may be revisiting this again in the future.

Thank goodness this didn't happen on any of the other 2 holes or the entire manifold would have needed to come out.

Question: Do you guys always change out the studs or just use a new bolt? I believe those aluminum bolts deform and lock in place but not sure if the aluminum studs do as well.

 

I reused the bolts. I dropped the downpipe out twice. Once for changing the downpipe, and the other to change the gasket (cuz I didn't do it the first time lol). No leaks or problems since.

 

I've only removed my DP once, and used new studs and bolts and didn't have any issues. Glad I did. Thanks for the write-up.

 

happened to me too,. But it came out with a struggle. I though i have it snapped off. ..... And guess what it was that same top one. :(

https://www.northamericanmotoring.co...questions.html





I changed mine out after that lesson , and its easy to get the new pipe in because the stud are shorter .

 

I almost ordered from ECS Tuning bit I found the exact same price minus the shipping cost at Montgomery County Mini.

2 more tips

-Make sure and change the metal gasket anytime you release tension from the bolts or you risk a leak. Hurts to toss $12 in the garbage but those gaskets are one use only.

-Make sure you put the 2 metal brackets that hold the downpipe to the engine block at the bottom of the downpipe IN THEIR FINAL POSITION before tightening the downpipe to the turbo. If you dont have the brackets in place, and tighten the downpipe to turbo the brackets wont fit behind the downpipe without removing the nuts and pulling the downpipe from the turbo/manifold at which point you will need to replace the nuts and gasket again. Ask me how I know?

 

Lex, thanks for the almost order

I got beaten apart by my hands trying the work it out. I swear the top one is rusted on there and heated from the intense heat cycles. That new hardware made it easy to bring the DP up from the bottom and hook on .


Here some more info about that gasket: You have to match it up as they used two designs at the time.

https://www.northamericanmotoring.co...-oil-line.html

 

Hey I order almost my parts from you guys. Your parts are usually cheaper and they get to the east coast fast unlike Pelican Parts. But you offered zero discount on these fasteners compared to the stealership plus the shipping charge...ouch!

 

Sorry we could not beat that price, sometimes the local dealerships will beat our price and take a hit to get business. :(

If you get an order over $200, we offer free ship, also I am always here to help. I have the beat up hands form working on 2 MINIs to prove it,


In the end I am glad you got it fixed, I know how it feels to have your car to mix things up on you.

 

Maybe I should have heated the stud and then sprayed it to cool it and then pulled it. However, most bolts that get so hot and then cold regularly with engine cycle don't get stuck like that since they expand and contract constantly. I think maybe the aluminum they use isn't the best idea. Too soft.

 

Yea, I think the studs rust into place. You would not think only one would do that. My bottom ones just came out with a quick turn of the vice grip.

 

So, buy new studs and gasket?
Mines sitting in living room, was going to wait till tune to install

 

I would and i did, before hand i match up the gaskets by looking at the end of the gasket installed. takes a good eye but you can see it.

 

You have to it will leak. At least buy 3 new aluminum nuts and gasket. But youre better off changing the studs as well or youll have to start from zero and pay for nuts and gasket again.

 

Another option is locking fasteners like: http://store.stage8.com/p/4926-4-cyl...bolt-kit?pp=24


...assuming they are long enough.

 

What a nightmare.

The top stud galled on me too. Luckily my tap didn't break when re-chasing the threads. Now I always use new studs.

 

Highly recommend the Stage8 locking fasteners!!

I have them on the turbo studs on my 280ZX Turbo.

 

Does Heat and PB Blast work??

 

yes, i had to heat mine up after the PB blaster would not work. PB doe work most of the time. this time the stud was stubborn.

 

Yep, new short studs from ECS or other supplier make the job easier.

 

Thanks