Technical MLS or Cutring Head Gasket?

IQraceworks

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Jul 7, 2020
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Missouri
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07' BMW 335i
I'm in the process or ordering all the parts I need to put my motor back together. It should make 575-ish hp at 25psi on a good E40 tune. I've seen a lot of contradicting information on N54 head gaskets.

Maybe the reason I don't see much talk about N54 head gaskets it because it's pretty rare to have problems with them...even the OEM MLS type.

Any reason not to go back to the OEM MLS type head gasket? Or should I spend double the money and go with one of the Athens or SCE Vulcan cutring type head gaskets? Any downside to running the cutring type gasket?

Just trying to educate myself a little bit. Thanks
 
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JohnDaviz

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Jan 6, 2019
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The trick is to torque down your head studs or oem screws. With the OEM Headbolts many ppl experience headlift around 600whp with a rebuild engine. I had it. The repair manual tells you how to do but it seems that it is not the exact same as it was done in the plant. So MLS will give you the challenge to do it right. Good Luck.
 

IQraceworks

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Jul 7, 2020
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Missouri
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07' BMW 335i
The trick is to torque down your head studs or oem screws. With the OEM Headbolts many ppl experience headlift around 600whp with a rebuild engine. I had it. The repair manual tells you how to do but it seems that it is not the exact same as it was done in the plant. So MLS will give you the challenge to do it right. Good Luck.

Thanks for the feedback...but I'm a little confused. The BMW manual tells you the exact way to torque down the bolts. And original OEM gasket was an MLS gasket. If the head and block are clean and flat, you use new oem bolts, and a new MLS gasket.....why would it be a challange to torque them right and get the head to seal correctly? How do you know the way it was done at the plant does not match teh way they tell you to do it in the BMW tech manual?

Do you mean some people just get lazy and don't torque them correctly?
 

carabuser

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Oct 2, 2019
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I don't think they mess around with a torque sequence in the factory for the N54. Torquing bolts down individually will always be sub-optimal.

This is a video of the B57 assembly or at least one of the newer engines:
You can see that they just have a robot that perfectly torques them all down at exactly the same time.

Maybe if you were doing this yourself and had time to spare and wanted to improve on the repair manual method you could stagger the torque sequence, so follow the sequence from the manual working outwards but do multiple passes at increasing torque values (20nm, 40nm, 60nm etc). In my mind that would be better as you reduce the pinching effect of one bolt being fully torqued alone.
 
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IQraceworks

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Jul 7, 2020
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Wow....that's pretty cool how they do that. If I had to bet, I'd say that most of the failures people have with using oem bolts is because they don't have the block and deck clean and flat, and they don't follow the BMW process for torquing. But who knows. I guess I will find out.
 

CalvinNismo

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Nov 1, 2020
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Elring head gaskets don’t sound like they have the best success rate on N54s. Check out the latest Zero to 60.
 

IQraceworks

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Jul 7, 2020
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Missouri
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07' BMW 335i
Elring head gaskets don’t sound like they have the best success rate on N54s. Check out the latest Zero to 60.
Wish I would have listened to you. My new Elring head gasket, with only 1000 miles on the new engine, is starting to seep coolant out of it between the block and head. Everything was checked for flatness, surfaces were cleaned and has correct 20RA finish on them, new oem head bolts, torqued/angled to the BMW specs........and the stupid gasket is seeping fluid out of it. I'm about ready to just jerk this N54 out and drop an LS in the car.

Going to see if FCP will let me exchange the bad Elring gasket and give me credit for it on a new BMW brand head gasket.

hkj7uNQ.jpg
 
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CalvinNismo

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Nov 1, 2020
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Sorry to read this! With the coolant managing to be visible ‘uphill’ like that, yeah, it’s crap. I hope the genuine gasket solves things for you!