stripped engine mount in block :(

rhodesman

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On a scale of 1 to OMG! how screwed am I right now? The stripped/crossthreaded bolt is the hole for the longest screw that holds the engine mount arm to the engine block right below the rear turbo. It took me a good 10-15 mins using a pry bar with an extension to be able to back the bolt out of the hole!!! :screamcat:

As far as I know, this was never taken off since the car was built as I've had the car from new and this is the first time I've ever removed the turbo's or removed enough of the engine's parts to necessitate removing the passenger side engine mount. I find it hard to believe it would have been crossthreaded/stripped from the factory but mistakes can happen and thus wouldn't rule it out completely. My car has also been in and out of the BMW service center for various reasons and warranty work over it's life but none of the work they have ever done on my car would have required them to remove the engine mount and unlikely it has ever been removed by them.

I'm not sure how best to proceed here. Obviously, I can't screw the bolt back in when I put the car back together but now I'm worried that can 3 of the 4 bolts be enough to hold the engine? I am in no position to buy a new engine block nor do I care to do so.

Can I make do with only 3 of the bolts?? Stupid car! :rage:
 

veer90

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Nov 16, 2016
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I'm using 3 out of 4 bolts on that bracket because I'm an idiot and installed my ST downpipe before putting that arm back. However the long bolt is installed, I'm missing one of the short bolts.

And I would use timesert over helicoil. Especially for something load bearing.
 
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JayG335

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Timesert and SEND IT friend. Really though you'll be ok. Plenty of room to work with over there with everything removed. Just take your time.
 
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dyezak

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I'm using 3 out of 4 bolts on that bracket because I'm an idiot and installed my ST downpipe before putting that arm back. However the long bolt is installed, I'm missing one of the short bolts.

And I would use timesert over helicoil. Especially for something load bearing.

Helicoil in aluminum is actually stronger than a raw threaded aluminum casting.
 

veer90

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I actually wasn't able to find a torque spec on those bolts, so I used the same cheater bar I used to remove the bolts to reinstall them lol

If I had to estimate I put at least 50 ft-lb on them if not more.
 

LoBoost

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As the others have stated, helicoil or timesert. Make the investment into one kit or the other and you will have piece of mind that you can fix it properly, and any other stripped threads that would happen in the future.
 

fmorelli

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Be careful of all these cheap as shit Helicoil kits on Amazon. The installation tools are all made out of soft steel - guess what happens when one drives a sharp stainless steel insert into a hole with a soft steel tool? Snags the soft steel and eats it. Better yet, it gets caught on the tool and lots of cussing ensues. I've returned two kits thus far.

I also own a time sert kit, which I used when I played with old BMW airhead motors. Time sert is the bomb ... but you'll be racking up the dollars on that...

Helicoil that sucker and call it a day. It's not a big deal - guys that build race aluminum heads and blocks often helicoil everything so they can run fasteners in and out without this crap happening constantly ...

Filippo
 
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R.G.

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@Milan nailed it

Helicoil ftw

Not difficult at all. Happened to my rear wheel carrier to control arm connection. Bolt worked itself loose and luckily it didn't fail until I was reversing out of a parking spot :openmouth:
Fixed years ago and it has held up like a champ. Still nervously check it on occasion o_O
 

buster84

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I actually wasn't able to find a torque spec on those bolts, so I used the same cheater bar I used to remove the bolts to reinstall them lol

If I had to estimate I put at least 50 ft-lb on them if not more.

I had the same question not to long ago and I couldn't find it from searching so I posted on how I found it. On my XI it said that it was 66NM for the n54 which is 48.68 ft lbs do your 50 ft lbs was about right since anything more could be bad. So depending on how good your torque wrench was and it's not cheap you should be exactly where you wanted. When it came to replacing my turbos I did every bolt that I touched to bmw spec and I've not had even one issue with my car. Taking your time to do it right saves future headaches and I feel bad for the op having to deal with a stripped bolt that someone else caused when assembling the engine.

https://bmw.spoolstreet.com/threads...ubframe-motor-mount-nm-specs.3376/#post-42629

Ok i found what i was looking for. This webite made it so easy to find exactly what i needed, I hope this link helps anyone else in the future looking to torque values.

https://www.newtis.info/tisv2/a/en/

https://www.newtis.info/tisv2/a/en/...ission-mounting/22-11-engine-mounting/P3ZQhuw
 
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TwinTurboWAWD

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Helicoil in aluminum is actually stronger than a raw threaded aluminum casting.
Alot of OEMs are doing this for strength and durability.
Some of the engines I work on have aluminum camshaft housings.
The rocker arm shafts bolt to this housing and torque 36-40 lb-ft plus an additional 90° torque turn on 10 mm threaded bolt. Which I've seen go 60-80lb-ft when monitoring the reading on my digital torque wrench as final bolt torque depending on bolt stretch.