N54 Head Stud holes messed up

pysical

Sergeant
Jun 16, 2017
471
108
0
Ride
2009 335xi E90
Had a machine shop drill the outer 4 9mm holes to 11mm. When I put the studs in, they are SUPER loose. Thread engagement is terrible and I doubt I could even get them torqued without threads stripping right out.

I talked to him and I have to send the block back and he said he would take a look at it. I asked what he would do to fix and he said maybe a helicoil or something else. I don't think a helicoil will work, if anything I was thinking a timesert.

Has anyone had something similar happen? Car will be making 800hp (AWD) so I need to make sure this is going to hold up. If it isn't going to work then I am going to have to get him to get me another block and he will then have to sleeve and close deck it since thats whats done to it now.
 

doublespaces

Administrator
Oct 18, 2016
9,303
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AZ
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2009 E93 335i
Had a machine shop drill the outer 4 9mm holes to 11mm. When I put the studs in, they are SUPER loose. Thread engagement is terrible and I doubt I could even get them torqued without threads stripping right out.

I talked to him and I have to send the block back and he said he would take a look at it. I asked what he would do to fix and he said maybe a helicoil or something else. I don't think a helicoil will work, if anything I was thinking a timesert.

Has anyone had something similar happen? Car will be making 800hp (AWD) so I need to make sure this is going to hold up. If it isn't going to work then I am going to have to get him to get me another block and he will then have to sleeve and close deck it since thats whats done to it now.

CTRL+Z

Find out what tool he used to make these threads. Then see if you can have studs made to match or go up a size if possible. I can't think of a good solution otherwise. A helicoil sounds like an awful idea, but I don't know anything about engine building. But ask him to hand you the actual tool he used to make the threads, I would be curious personally.
 
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pysical

Sergeant
Jun 16, 2017
471
108
0
Ride
2009 335xi E90
Well its 10 hours away. I have to send the block. I don't want to bash on the place(yet) but they are familiar with N54s.

I have been trying to do research about this and seems like the best option is going to use a Time-Sert. This article here https://dsportmag.com/the-tech/how-to-increase-the-power-handling-of-any-engine/ actually makes it sound like it makes it stronger.

My biggest concern is I don't want to put a bandaid solution in it only to constantly worry that something might happen.
 

doublespaces

Administrator
Oct 18, 2016
9,303
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AZ
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2009 E93 335i
Well its 10 hours away. I have to send the block. I don't want to bash on the place(yet) but they are familiar with N54s.

I have been trying to do research about this and seems like the best option is going to use a Time-Sert. This article here https://dsportmag.com/the-tech/how-to-increase-the-power-handling-of-any-engine/ actually makes it sound like it makes it stronger.

My biggest concern is I don't want to put a bandaid solution in it only to constantly worry that something might happen.

I've got time serts in my F30 brake calipers. You can certainly argue they are like sleeves for each stud and I know they make them different lengths, I just haven't heard of someone doing this. I'm curious to see what other people say.
 

V8bait

Lieutenant
Nov 2, 2016
500
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Texas
Time sert should be fine if there's enough room and they get the thread right this time.

Been done plenty of times on many aluminum blocks that have lifting issues.
 
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pysical

Sergeant
Jun 16, 2017
471
108
0
Ride
2009 335xi E90
I would feel fine if this was going back together stock. But aiming for 800~HP I am worried that it might not hold.
 

Rob09msport

Major
Oct 28, 2017
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09 335i msport le mans 18 x5
I would def go up in size if that's possible . Is their any chance it's the wrong thread pitch or something?
 

pysical

Sergeant
Jun 16, 2017
471
108
0
Ride
2009 335xi E90
I would def go up in size if that's possible . Is their any chance it's the wrong thread pitch or something?

TBH i am not sure what the deal is. My brother thinks the guy did it to fast or no lubricate and possibly pulled more material than it should have. But it is a good chance they ordered the wrong tap.

I don't know if I can go up another size. Because two of these holes use dowels so i can only go as big as those. Else, I will have to get some sort of custom dowel created and drill the head to fit it.

This pisses me off because I have been waiting 4 months for this block to be done, and now its fucked.
 

Rob09msport

Major
Oct 28, 2017
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I would think wrong tap is correct. I know alot of the m3 guys have done the timecerts I know its diff block but they weren't designed for boost so they need modification. Helicoil I would not trust one bit though they don't even last for spark plug on my vans .
 

pysical

Sergeant
Jun 16, 2017
471
108
0
Ride
2009 335xi E90
I might have a solution. I may be able to drill them out to 12mm and get custom studs made that go down to 11mm soon as it leaves the block