E90Post
 


GetBMWParts
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > NA Engine (non-turbo) / Drivetrain / Exhaust Modifications > Magnesium block?



Reply
 
Thread Tools Search this Thread
      11-23-2010, 11:43 AM   #1
sredwine
New Member
 
Drives: 2007 328i 6S Sport Pkg
Join Date: Sep 2010
Location: Atlanta

Posts: 19
iTrader: (0)

Magnesium block?

I have read that BMW introduced a magnesium-clad block structure in the '06 E90. A mechanic told me they had problems with that block failing (and I've seen at least one bulletin discussing block failure-causes incurable oil leak) and reverted to a more conventional aluminum block for '07-my year, coincidentally. Anyone have any more info on this? If the blocks are aluminum, we shouldn't have to use those stupid aluminum bolts, either!
sredwine is offline  
0
Reply With Quote
      11-23-2010, 03:08 PM   #2
micah_675
Second Lieutenant
 
Drives: 2006 325i (US Spec)
Join Date: Sep 2010
Location: Germany

Posts: 253
iTrader: (0)

To my knowledge all N52 motors are Magnesium block/Aluminum sleeved blocks. Meaning the Cylinder walls are aluminum and the outside block is magnesium. Magnesium is a very strong and light metal. FYI sikorsky MH-53 main gear boxes are made out of magnesium. If its good enough to cary a 42k pound Helo into the air, its damn sure good enough to handle your 250 hp......


From BMW's website:
Quote:
Our inline six engine offers smooth power, greater acceleration and 200 lb-ft of torque at at 2750 rpms. A number of pioneering technologies make it possible. An electronically controlled water pump helps increase power output. Our patented Valvetronic system offers better fuel efficiency. And to save weight, we used a groundbreaking innovation that BMW was the first to use in a production car - an engine block made of a lightweight composite magnesium/aluminum.

Last edited by micah_675; 11-23-2010 at 03:25 PM.
micah_675 is offline  
0
Reply With Quote
      11-23-2010, 09:17 PM   #3
micah_675
Second Lieutenant
 
Drives: 2006 325i (US Spec)
Join Date: Sep 2010
Location: Germany

Posts: 253
iTrader: (0)

You sir are full of crap. TY for wasting more peoples time with more spouted off garbage you THINK you know. Guess what, NO it isn't a fire hazard. If it was why would they be able to build it? The flash point of magnesium is COMPLETELY dependent on the amount and FORM of the metal. Shavings or flakes WILL combust rather easily, however a large piece, such as an engine block, will not. Take your trash elsewhere. The block is a magnesium alloy. http://www.eurosinolink.com/pdf/sdpm020v1mg.pdf

Oh and i would like to point out Milk of Magnesia is a GREAT anti-seize and anti-corrosion device. Which is utilized as such in aircraft motors (which oddly enough doesnt catch on fire huh).

Quote:
Originally Posted by TrackRat View Post
Magnesium's biggest asset is light weight. It has many pitfalls however including brittleness, low cyclical fatigue life, corrosion issues, easily stripped machine threads, etc. Numerous car makers have used magnesium engine/trans cases over the years for production and they always revert to aluminum after a few years of Hell with the magnesium parts. Aside from the obvious fire hazard, magnesium is popular in racing for throw away parts.

IME magnesium has a very limited usefulness to date for street vehicles.

In addition to BMW using a composite engine block they decided to use aluminum cam cover bolts which regularly fracture and cause a $1000+ repair bill.

Last edited by micah_675; 11-23-2010 at 09:26 PM.
micah_675 is offline  
0
Reply With Quote
      11-23-2010, 10:06 PM   #4
Mike.Beale
New Member
 
Drives: 2008 128i & 2005 Lotus Elise
Join Date: Oct 2010
Location: Orange County, CA

Posts: 28
iTrader: (0)

I agree with micah_675 that the fire hazard from magnesium is essentially non-existant. At the same time some of TrackRat's points are valid. There are issues with cracking and corrosion in magnesium. Even though mag has been used sucessfully in the past by Sikorsky and other aerospace companies, 'no magnesium' has been one of the ground rules on the aerospace programs that I have worked on. This is mainly due to the corrosion problems that the Navy and the airlines have had with mag. Note though that both the military and airlines look for a 30 year life span for their aircraft with very harsh environmental requirements. So just because its not acceptable for aerospace anymore doesn't mean it can't be used for cars.

Both VW and Porsche have used mag quite sucessfuly in their air-cooled engines. Eventually both companies went to aluminum cases. I think this was because as they increased the power and displacement of their engines they eventually needed to strengthen the cases. Switch to a stronger allow was a quicker and easier change compared with designing a whole new beefed up mag case.
Mike.Beale is offline   United_States
0
Reply With Quote
      11-23-2010, 10:08 PM   #5
issabmw
cool beans
 
Drives: E30|E90|Godzilla
Join Date: Mar 2010
Location: Sunshine State

Posts: 1,364
iTrader: (2)

Quote:
Originally Posted by Mike.Beale View Post
I agree with micah_675 that the fire hazard from magnesium is essentially non-existant. At the same time some of TrackRat's points are valid. There are issues with cracking and corrosion in magnesium. Even though mag has been used sucessfully in the past by Sikorsky and other aerospace companies, 'no magnesium' has been one of the ground rules on the aerospace programs that I have worked on. This is mainly due to the corrosion problems that the Navy and the airlines have had with mag. Note though that both the military and airlines look for a 30 year life span for their aircraft with very harsh environmental requirements. So just because its not acceptable for aerospace anymore doesn't mean it can't be used for cars.

Both VW and Porsche have used mag quite sucessfuly in their air-cooled engines. Eventually both companies went to aluminum cases. I think this was because as they increased the power and displacement of their engines they eventually needed to strengthen the cases. Switch to a stronger allow was a quicker and easier change compared with designing a whole new beefed up mag case.
You make very valid points
issabmw is offline   Lebanon
0
Reply With Quote
      11-23-2010, 10:18 PM   #6
issabmw
cool beans
 
Drives: E30|E90|Godzilla
Join Date: Mar 2010
Location: Sunshine State

Posts: 1,364
iTrader: (2)

I think the OPs take on this is from a performance standpoint. The reasoning behind the magnesium block is to save weight, which I think we all can agree on.

The block is sleeved with aluminum, meaning it retains the strength of an aluminum block where it counts: the combustion chamber, while giving a lightweight housing for placement of the internals.

Now, to what degree are the blocks sleeved i.e. thickness, and how much power would it take for the block to give up is a matter of testing.

For the power we have, its a great design. I personally think that //M should give us an iron block to work with again, like the S54 in the e46, which handled extreme turbocharged setups.
issabmw is offline   Lebanon
0
Reply With Quote
      11-23-2010, 10:42 PM   #7
FrankiE90
Major General
 
FrankiE90's Avatar
 
Drives: Krooked Sk8board
Join Date: Feb 2008
Location: Pasadena, Ca

Posts: 8,628
iTrader: (11)

Send a message via Skype™ to FrankiE90
__________________
FrankiE90 AKA:.[The TANK] *CLICK THE SIG
2011 335 E90 MTECH 6MT KW V3 INJEN Intake Berk 4" DP Vanguard V2 exhaust Procede V5 Stoptech BBK RPI Scoops Karbonwerk CSL Trunk LUX H8 19" BBS LM 18" BBS GT4
FrankiE90 is offline   United_States
0
Reply With Quote
      11-24-2010, 12:27 AM   #8
5erman
Banned
 
Drives: black 5 series
Join Date: May 2009
Location: ohio

Posts: 324
iTrader: (0)

people keep saying aluminum is stronger-magnesium is a much stronger metal foilks--
5erman is offline  
0
Reply With Quote
      11-24-2010, 10:22 AM   #9
jaguar36
Second Lieutenant
 
jaguar36's Avatar
 
Drives: 2010 E92 335i
Join Date: Oct 2009
Location: Cherry Hill, NJ

Posts: 247
iTrader: (0)

Quote:
Originally Posted by TrackRat View Post
Please stop your inappropriate posts micah 675-
+1

Magneisum has some great properties, but the fire issue cannot be ignored. The flash point of a material is the same regardless of its form. It is 500C in a shaving or a block. (It is however alot easier to get a shaving to 500C than an engine block) It is quite difficult to get a large hunk of Magnesium to burn, however it can happen, and when you are talking about hundreds of thousands of cars, the chances of it happening are not insignificant.

Quote:
Originally Posted by 5erman
people keep saying aluminum is stronger-magnesium is a much stronger metal foilks--
This is also not technically true. The tensile yield strength of Magnesium ranges from about 21-25ksi. Some Aluminum alloys have a tensile yield strength of >60ksi. (For comparison, some steels can get over 200ksi). However this doesn't tell the whole story as Magneisum is very light at only 1.7 g/cm^3 vs Aluminum at 2.7, and steel at 7.9.

Material selection is never as simple as which one is the strongest, or lightest. A whole range of features including strength, density, stiffness, fatigue, corrosion, availability, cost, machinability and so on have to be considered.

And lastly... micah_675 you lost any spec of credibility you had when you brought up Milk of Magnesia, Milk of Magnesia is Magnesium hydroxide (Mg(OH)2) and is as similar to Magnesium as Oxygen is to water.
jaguar36 is offline  
0
Reply With Quote
      11-24-2010, 10:26 AM   #10
TSM330i
2006 330i, TSM, Black, manual, sport
 
TSM330i's Avatar
 
Drives: E90 330i, E86 Z4 3.0si
Join Date: Nov 2005
Location: Chester Springs, PA

Posts: 3,024
iTrader: (2)

They still use the mag/aluminum block.

Here's one of the highlights from the brand new X3 6-cylinder engine.
http://www.bmwusa.com/Standard/Conte...rformance.aspx
__________________
2006 330i, TSM, Black, Sport, JIC Cross Coil-Overs, UUC Sways, 18" Advan RS, Mich PSS 255/265, BMW Electric Steering Wheel, Rogue shifter, M-Tech front, CF emblems, Dinan TB, Intake, exhaust, strut bar, Stoptech BBK, LSD, M3 susp., LUX 5, CF Hood and CSL, Sparco Seats, AA tune, CF Roof
TSM330i is offline   United_States
0
Reply With Quote
      11-24-2010, 02:24 PM   #11
sredwine
New Member
 
Drives: 2007 328i 6S Sport Pkg
Join Date: Sep 2010
Location: Atlanta

Posts: 19
iTrader: (0)

Lots of good info here, and well-informed opinions. I'm not worried about the magnesium part of my block catching fire-if the car gets hot enough to ingnite that mass, I've probably got more than enough trouble already! The scary bulletin I found mentions an incurable oil leak between the aluminum and magensium sections (I believe) that occurs low on the right front of the bloock near the coolant pump location. New block would be only fix. The stupid, fragile aluminum bolts are used because the magnesium block has severe galvanic corrosion problems if steel is used. Now what has me posting all this is the mechanic I took the car to (pre-purchase) said they phased the magnesium block out after '06 MY but kept using the aluminum bolts to avoid confusion in the shop. He had been a mechanic at one of our top dealerships for years and had the certificates to prove it-but he could have been fed BS by BMW-anybody have some insight here?
sredwine is offline  
0
Reply With Quote
      11-24-2010, 02:39 PM   #12
jaguar36
Second Lieutenant
 
jaguar36's Avatar
 
Drives: 2010 E92 335i
Join Date: Oct 2009
Location: Cherry Hill, NJ

Posts: 247
iTrader: (0)

That is partially correct. In 2006 BMW offered the 325i and the 330i, both of which used the N52 engine which has the Magnesium block with aluminum clyinder liners. In 2007 the E90s switched to the 328i and 335i. The 328i continues to use the N52 engine, while the 335i uses the less sophisticated N54 engine, which has an aluminum block with cast iron cylinder liners.
jaguar36 is offline  
0
Reply With Quote
      11-26-2010, 10:36 AM   #13
micah_675
Second Lieutenant
 
Drives: 2006 325i (US Spec)
Join Date: Sep 2010
Location: Germany

Posts: 253
iTrader: (0)

@ the OP your block is still the exact same as all the N52 motors. You have the magnesium/aluminum composite block (just means they are 2 different pieces of metals pushed (mechanically fused) together). As for you worrying about your block leaking. It shouldn't be a major issue. I am sure there was defects in the metal that caused the issue.



I don't particularly care what you 2 think. The block is a magnesium alloy. Therefore let me break it down. Alloys are made of one or more metal, there is always one that makes up more of the substance than the other (typically the primary metal is what is named for the alloy). Why are alloys used? Because when properly created the strengths of the metals combined are left and typically leave the weaknesses out. Regardless, it is VERY well documented that is near impossible to ignite an ingot of magnesium. Only in its molten state does it become unstable and HIGHLY combustible.

Quote:
The BMW engine uses an aluminium alloy insert for the cylinder walls and cooling jackets surrounded by a high-temperature magnesium alloy AJ62A
The makeup of our engine block is as follows, 91.7% Mg, 6% Al, 2% Sr, and 0.3% Mn. Which is a creep-resistant Mg alloy blend. Basically meaning it resists thermal and physical stress trying to tear the metal apart.

Sources

Makeup of the alloy on page 681 (also goes in depth about creep testing on the alloys mentioned in the article including AJ62A (our engine block))

http://books.google.com/books?id=WIG...page&q&f=false

mathematical formula for computation of creep characteristics and description of creep

http://personnel.mcgill.ca/files/mih...uz/kayaadv.pdf

Any questions? I would like to point out that cracking is not going to be a major issue. Why? Because your actual cylinder walls are Aluminum NOT the magnesium alloy.

A good fact sheet about magnesium

http://www.magnesium.com/w3/data-bank/index.php?mgw=222

Quote:
Magnesium is an excellent conductor of heat, and, as a practical matter, the entire piece must be brought to a temperature near the melting point before ignition will occur. Normally, this will not occur unless the solid magnesium piece is surrounded by a general conflagration from other sources.
micah_675 is offline  
0
Reply With Quote
      11-27-2010, 12:26 AM   #14
dirnegrey
Colonel
 
dirnegrey's Avatar
 
Drives: m3 vert
Join Date: Apr 2009
Location: Seattle, WA

Posts: 2,003
iTrader: (8)

Quote:
Originally Posted by micah_675 View Post
You sir are full of crap. TY for wasting more peoples time with more spouted off garbage you THINK you know. Guess what, NO it isn't a fire hazard. If it was why would they be able to build it? The flash point of magnesium is COMPLETELY dependent on the amount and FORM of the metal. Shavings or flakes WILL combust rather easily, however a large piece, such as an engine block, will not. Take your trash elsewhere. The block is a magnesium alloy. http://www.eurosinolink.com/pdf/sdpm020v1mg.pdf

Oh and i would like to point out Milk of Magnesia is a GREAT anti-seize and anti-corrosion device. Which is utilized as such in aircraft motors (which oddly enough doesnt catch on fire huh).
Magnesium IS fire hazard. even little kid know that.
__________________
Current:
2006 Maserati Quattroporte S (Bianco Eldorado)
Sold:
2007 BMW 328i (Jet Black)
2002 BMW M3 (TiAg)
dirnegrey is offline   United_States
0
Reply With Quote
      11-29-2010, 10:34 AM   #15
jaguar36
Second Lieutenant
 
jaguar36's Avatar
 
Drives: 2010 E92 335i
Join Date: Oct 2009
Location: Cherry Hill, NJ

Posts: 247
iTrader: (0)

It is certainly possible for a magnesium engine block to ignite. It is also highly unlikely. However like I said before when you have hundreds of thousands of them running around, a one in a million chance becomes pretty likely.

Regardless its pretty irrelevant for the car owner, by the time the block would go up you'd be long dead if you were in the car. Its really only an issue for firefighters (and the guys who would have to come fix the road after your engine block melted a hole through it). Firefighters have to know not to use water on a magnesium fire as magnesium burns so hot that it will decompose the water into hydrogen and oxygen, which will just make the fire worse.
jaguar36 is offline  
0
Reply With Quote
      12-15-2010, 06:18 PM   #16
Gavin@MMW
Brigadier General
 
Gavin@MMW's Avatar
 
Drives: MMW Supercharged E90 328i
Join Date: Nov 2009
Location: 818/805

Posts: 3,902
iTrader: (18)

Quote:
Originally Posted by micah_675 View Post
@ the OP your block is still the exact same as all the N52 motors. You have the magnesium/aluminum composite block (just means they are 2 different pieces of metals pushed (mechanically fused) together). As for you worrying about your block leaking. It shouldn't be a major issue. I am sure there was defects in the metal that caused the issue.



I don't particularly care what you 2 think. The block is a magnesium alloy. Therefore let me break it down. Alloys are made of one or more metal, there is always one that makes up more of the substance than the other (typically the primary metal is what is named for the alloy). Why are alloys used? Because when properly created the strengths of the metals combined are left and typically leave the weaknesses out. Regardless, it is VERY well documented that is near impossible to ignite an ingot of magnesium. Only in its molten state does it become unstable and HIGHLY combustible.



The makeup of our engine block is as follows, 91.7% Mg, 6% Al, 2% Sr, and 0.3% Mn. Which is a creep-resistant Mg alloy blend. Basically meaning it resists thermal and physical stress trying to tear the metal apart.

Sources

Makeup of the alloy on page 681 (also goes in depth about creep testing on the alloys mentioned in the article including AJ62A (our engine block))

http://books.google.com/books?id=WIG...page&q&f=false

mathematical formula for computation of creep characteristics and description of creep

http://personnel.mcgill.ca/files/mih...uz/kayaadv.pdf

Any questions? I would like to point out that cracking is not going to be a major issue. Why? Because your actual cylinder walls are Aluminum NOT the magnesium alloy.

A good fact sheet about magnesium

http://www.magnesium.com/w3/data-bank/index.php?mgw=222
This is good information right here^^
Gavin@MMW is offline   United_States
0
Reply With Quote
      12-18-2010, 11:45 AM   #17
Spitfirocks
Lieutenant
 
Drives: 335i 07
Join Date: Sep 2008
Location: NJ

Posts: 565
iTrader: (5)

I love lighting magnesium strips on fire! It is a beautiful sight(or lack of, because you can never look directly at it)
Spitfirocks is offline  
0
Reply With Quote
      12-18-2010, 12:01 PM   #18
philsteroni
Private First Class
 
Drives: 325xi
Join Date: Apr 2009
Location: Montreal

Posts: 144
iTrader: (1)

This topic makes me laugh because 20 years ago BMW introduced aluminum blocks to the car industry with the e36 model. They had a recall on them and everyone started to put in their 2 cents about how BMW was stupid for using aluminum blocks... Now every car manufacturer uses aluminum for their engine blocks. Why don't we all learn from history and let the BMW (industry leading) engineers do the thinking.
philsteroni is offline   Canada
0
Reply With Quote
      12-18-2010, 03:20 PM   #19
superduty
Private First Class
 
superduty's Avatar
 
Drives: 2010 E91 M Sport
Join Date: Dec 2009
Location: Tucson, Az

Posts: 116
iTrader: (0)

I hope you aren't saying that BMW was the first manufacturer to produce aluminum blocks.

Quote:
Originally Posted by philsteroni View Post
This topic makes me laugh because 20 years ago BMW introduced aluminum blocks to the car industry with the e36 model. They had a recall on them and everyone started to put in their 2 cents about how BMW was stupid for using aluminum blocks... Now every car manufacturer uses aluminum for their engine blocks. Why don't we all learn from history and let the BMW (industry leading) engineers do the thinking.
__________________
"Did I say something abnormal?"
"You're an engineer, everything you say is abnormal."
superduty is offline   United_States
0
Reply With Quote
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 02:23 PM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST