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Fri Nov 29, 2013 6:04 am

Their are those who seem to favor Magnesium over aluminum engine cases . One factor most list is the weight difference, I saw a video of a 1935 Bugatti and the body was totally magnesium, they said that because of the weight that it was like the carbon fiber of its day, the reason I bring this up was, they were saying how difficult the metal was to work with because of it’s hardness, and even though the car has been restored, the body panels still require attention from time to time for repair, I assume from cracking. I’m not a metallurgist, and I thought I read it on the forum that their are type 4 engine cases that are aluminum, is that correct ? if so why did VW go from a harder metal to a softer metal for that motor

Fri Nov 29, 2013 6:31 am

Why I like aluminum cases: Because the alumag alloy used in the T1 case will get pounded out in the main bearings after many hard miles, the aluminum ones aren't doing that so far as I've seen. Also I'm turbo, so I need as stout a case as I can get to avoid DD trouble.

The T4 engines were going to see a lot more abuse from pushing around a heavy Bus, so they got a better die case aluminum case. They also got a much better head design and very thick cylinders, that's why they last forever when you put one in a lighter Beetle.

Fri Nov 29, 2013 6:55 am

So it's an alloy (alumag ) but I don't understand if the mag is a harder metal wouldn't you think it would take more of a pounding ? or is it because VW mixed the two metals together it weakened its properties, I also run a aluminum case,

Fri Nov 29, 2013 7:28 am

The Magnesium vs Aluminum question has come up many times over the past 7+ years.

http://www.thesamba.com/vw/forum/viewtopic.php?t=495313
http://www.thesamba.com/vw/forum/viewtopic.php?t=549394
http://www.thesamba.com/vw/forum/viewtopic.php?t=494407
http://www.thesamba.com/vw/forum/viewtopic.php?t=451304
http://www.thesamba.com/vw/forum/viewtopic.php?t=180421

Fri Nov 29, 2013 8:13 am

Here's the same replies, doesn't answer my question

Magnesium has worked for me for the past 35 years.
Aluminum is much heavier then Mag.
Aluminum cases are around 20lbs heavier than a traditional Mag case
Type 4 cases are die cast. The aluminum type I cases are sand cast
Aluminum cases are now cheaper (new) then mag cases,
Why do you want to use an aluminum block when the factory magnesium cases are better

I don't see the answer in any of those replies to my question that I posted, now if it;s listed in any of those links that posted, please copy and paste it and thank you MIniman2, I didn't know it was an alloy, and if you look at the responses I've pasted they all refer to Mag cases

Fri Nov 29, 2013 8:29 am

First off, just because a metal is harder doesn't mean that it's stronger. In an engine case, you want strength. The (various) magnesium alloys used in the type 1 engines were primarily chosen for weight savings. The engines didn't produce much power from the factory, and didn't need massive strength. When the type 4 was being designed, they were using it to create a significant increase in power, and they were putting it in heavier cars. The aluminum alloy used in the type 4 case is stronger (may or may not be softer, I'd have to look it up), but heavier.

The magnesium also transfers heat better, leading to a slightly lower heat load on the various cooling mechanisms, but I don't know if that factored into the engineer's consideration.

Fri Nov 29, 2013 9:45 am

Aluminum cases are going to expand less than mag when the engine heats up. This means that you are going to have higher oil pressure and that your valve train is not going to get pounded out from the engine expanding. Look around at engines in cars today, they are all aluminum. Corvair blocks and porsche cases are also aluminum. Aluminum will likely not need an align bore for at least 3 rebuilds so there's that too.

Fri Nov 29, 2013 10:52 am

the aluminum can also pound out,hell there are plenty of iron blocks that need lineboring. but I like the aluminum cases because there made for performance apps.....how many mag cases were??? and they can be welded by just about any body easely with out fail or searching for mag filler rods. and aluminum...there thicker, much thicker and seem to be avalible new,Ive bought 1 new mag case and 2 new aluminum cases for my toys/projects.I have no reason to ever buy another mag case.let the "pureist" keep them.

Fri Nov 29, 2013 11:28 am

The idea of an aluminum engine case is really just fine. Aluminum has less tendency to creep or crack, so it holds up way better.
Magnesium isn't hard.....maybe compared to plastic it is, but it's not a very hard metal. It is very light. It does not transfer heat much faster.

If VW had made a nice die-cast aluminum engine case like the type-4 or WBX for the type-1 then it would probably be the tops.

The aftermarket aluminum cases are just the same as the mag case but far thicker and made of aluminum, which does work, but could be a lot better.

Fri Nov 29, 2013 12:16 pm

Modok and Mark,
I've learned a great deal from both of you and always enjoy your input , I'm going to post a link to the Magnesium car and take a listen to what they have to say about the car and Magnesium and that's what got me wondering about this whole metal concept
http://www.jaylenosgarage.com/video/1935-bugatti-aerolithe-coupe/n40553/

Fri Nov 29, 2013 12:31 pm

I do believe the mag cases are softer, I've drilled into aluminum (not a vw case application) in past, and it is pretty tough stuff. I've flowed a vw mag case and man that stuff felt like playdough compared to the aluminum. The aluminum I drilled was motorcycle frame grade, so maybe that is way different than the aluminum, or aluminum mix grade in vw cases. I always thought though that the softer mag cases would radiate heat better than aluminum, but I don't know enough to be sure about that, just an assumption on my part, that I believe, as do others here, to be true.
But I do know thick Aluminum is very, very, very, strong stuff for sure, way stronger than mag, there is no doubt about that.
I've heard the weight of an aluminum vw case is anywhere from 17 - 25 pounds, yet to get a straight answer on that.

Fri Nov 29, 2013 5:10 pm

Have you guys ever seen a VW on fire? That mag crankcase really goes. I watched a VW burn in Germany that was set on fire by a GI who was heading home and didn't want to pay the disposal fees for his worn out bug. So he stripped it of anything personal. took it to a local gravel pit and torched it. It burned for quite a long time and even in the daylight it was hard to look at. I think they caught him anyway. I know that here in Canada the roads departments used to thank the fire departments profusely if they got a burning VW dragged off the asphalt before it burned a veritable pot hole to China. I doubt it, but I wonder if some of those incidents didn't have something to do with changing to aluminum? Fred

Fri Nov 29, 2013 5:20 pm

Fred Winterburn wrote: Have you guys ever seen a VW on fire? That mag crankcase really goes. I watched a VW burn in Germany that was set on fire by a GI who was heading home and didn't want to pay the disposal fees for his worn out bug. So he stripped it of anything personal. took it to a local gravel pit and torched it. It burned for quite a long time and even in the daylight it was hard to look at. I think they caught him anyway. I know that here in Canada the roads departments used to thank the fire departments profusely if they got a burning VW dragged off the asphalt before it burned a veritable pot hole to China. I doubt it, but I wonder if some of those incidents didn't have something to do with changing to aluminum? Fred
If a car fire is hot enough to ignite the case, the car is already too far gone.

I've seen over a dozen VW fires and never seen one where the case ignited.

--------------------------------------------------------------

I've built over 30 VW engines all with stock magnesium cases and not a single one had a case failure. These range from stock 40hp to a 2332.

My only experience with an aluminum case was a customer came in with a oil leak. There was a sand casting defect and a small hole would open up when the engine heated up and it would leak. The case was also porous and weeped. We swaped it for a mag case and the customer never had another leak. The base aluminum case weighed a ton empty.

Fri Nov 29, 2013 6:12 pm

VW used 2 magnesium alloys for type I cases.

AS21 = 2% aluminum & 1% silicon
AS41 = 4% aluminum & 1% silicon

Doesn't matter anymore as VW has discontinued making the factory mag case and all that is available now are the aftermarket aluminum cases.

Fri Nov 29, 2013 7:08 pm

Glenn wrote: Fred Winterburn wrote: Have you guys ever seen a VW on fire? That mag crankcase really goes. I watched a VW burn in Germany that was set on fire by a GI who was heading home and didn't want to pay the disposal fees for his worn out bug. So he stripped it of anything personal. took it to a local gravel pit and torched it. It burned for quite a long time and even in the daylight it was hard to look at. I think they caught him anyway. I know that here in Canada the roads departments used to thank the fire departments profusely if they got a burning VW dragged off the asphalt before it burned a veritable pot hole to China. I doubt it, but I wonder if some of those incidents didn't have something to do with changing to aluminum? Fred
If a car fire is hot enough to ignite the case, the car is already too far gone.

I've seen over a dozen VW fires and never seen one where the case ignited. Ive seen pics of one with the crank& rods,jugs hanging there,no case in sight

--------------------------------------------------------------

I've built over 30 VW engines all with stock magnesium cases and not a single one had a case failure. These range from stock 40hp to a 2332.

My only experience with an aluminum case was a customer came in with a oil leak. There was a sand casting defect and a small hole would open up when the engine heated up and it would leak. The case was also porous and weeped. We swaped it for a mag case and the customer never had another leak. The base aluminum case weighed a ton empty.

Fri Nov 29, 2013 7:33 pm

The bugatti car sure is a neat snapshot of what high-tech was at that time, a lot of from aircraft technology. thousands of flush rivets?!! whoa

Good thing japan didn't figure out how to make magnesium bodied zeros! :shock:

Fri Nov 29, 2013 9:05 pm

stault wrote: Their are those who seem to favor Magnesium over aluminum engine cases . One factor most list is the weight difference, I saw a video of a 1935 Bugatti and the body was totally magnesium, they said that because of the weight that it was like the carbon fiber of its day, the reason I bring this up was, they were saying how difficult the metal was to work with because of it’s hardness, and even though the car has been restored, the body panels still require attention from time to time for repair, I assume from cracking. I’m not a metallurgist, and I thought I read it on the forum that their are type 4 engine cases that are aluminum, is that correct ? if so why did VW go from a harder metal to a softer metal for that motor

What makes you think the type 1 mag cases are harder and the the type 4 cases softer?
The aluminum cases are way stronger.

Sat Nov 30, 2013 6:14 am

Go check the video out that I posted ,that's what got me thinking

Sat Nov 30, 2013 10:48 pm

the mag is much easyer to manufacture ,cutting speeds,fluids,etc, the gallys are even cast right into the case,no need to drill all the gallys,that in it's self is a big time&tool saver.remember these were cheep cars....at one time.

Sat Nov 30, 2013 11:30 pm

yep what Mark said.
Also Mag cases are cheaper to make...