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Sun Jul 30, 2006 5:58 pm

hey what do you guys think is the best case to go with?

Sun Jul 30, 2006 6:06 pm

soazvw wrote: hey what do you guys think is the best case to go with?
AS41 is far better, and more than adequate for running in the 10's

Sun Jul 30, 2006 6:09 pm

whats the differeance?

Sun Jul 30, 2006 6:13 pm

soazvw wrote: whats the differeance?
AS41 is an alloy of magnesium, whereas aluminium blocs are made with an aluminium alloy.
AS41 are far lighter, have do not have tooling problems.
the choice of an aluminium bloc have to be considered only for 82/86mm cranks, because you have not to use spacers under the cylinders, the siting area is far thicker

Sun Jul 30, 2006 6:15 pm

I like the as41, but with all the aluminiums ones on the market, I finally got one. First impression, it's heavy.

So far it checks out, but I haven't started the motor yet.

Sun Jul 30, 2006 6:20 pm

jamestwo wrote: I like the as41, but with all the aluminiums ones on the market, I finally got one. First impression, it's heavy.

So far it checks out, but I haven't started the motor yet.
of course
density of magnesium 1.8
density of aluminium 2.7.
50% more weight.

evry time peaple tell me about alu, I report what say Ian Clark in GB
"aluminium bloc is probably better, but I dont need it."
He ran in the mid 10's :twisted:

Sun Jul 30, 2006 7:54 pm

True, been a diehard AS41 advacate, but the Aluminium is about 200 cheaper, because it comes bored for larger cylinders, full flowed and no need to sleeve lifter bores.

We will see :D

Sun Jul 30, 2006 9:43 pm

What was/is the purpose of making an aluminum block to begin with? is there some benefit to it?

Sun Jul 30, 2006 10:17 pm

propflux01 wrote: What was/is the purpose of making an aluminum block to begin with? is there some benefit to it?
Aluminum is stronger and therefore more crack resistant. After having two magnesium cases get cracked oil galleys, I like the option of aluminum. More importantly, the foundry was probably trying to reduce the ammount of magnesium casting it had to do, since most of its work is aluminum.
propflux01 wrote: AS41 are far lighter, have do not have tooling problems.
What tooling problems are you refering too? I haven't noticed any machining problems with the aluminum cases. They're certainly easier to weld for full flow oiling.

Mon Jul 31, 2006 12:21 am

1200RS wrote: jamestwo wrote: I like the as41, but with all the aluminiums ones on the market, I finally got one. First impression, it's heavy.

So far it checks out, but I haven't started the motor yet.
of course
density of magnesium 1.8
density of aluminium 2.7.
50% more weight.

evry time peaple tell me about alu, I report what say Ian Clark in GB
"aluminium bloc is probably better, but I dont need it."
He ran in the mid 10's :twisted:

People allways think in 1 dimension when they like to put somthing down. But how long will that as41 last doing 10's?

I'm no advocate of the alu case, but people seem to miss that if it turns out to be as strong as the type4 case, you may be able to do 200,000 hard miles open it up and find no line bore is needed and the mains have not become battered from high gear luggin.

There should be long term benifits, keep that in mind.

:D

Oh and this question gets covered about once a month, can we have a sticky to follow what people have found whiule using them.

:wink:

Mon Jul 31, 2006 3:00 am

krusher wrote: [
Oh and this question gets covered about once a month, can we have a sticky to follow what people have found whiule using them.

:wink:

Okee Dokee, but let's keep it n topic.

Mon Jul 31, 2006 5:09 pm

so for dirveability and reliability i should go with a alu block because it is stronger?

Mon Jul 31, 2006 5:11 pm

soazvw wrote: so for dirveability and reliability i should go with a alu block because it is stronger?

No.

Most if not all of the aluminum cases are sand cast and are brittle.

Tue Aug 01, 2006 11:07 am

8) Just built a 2110 alu block. Will put in on the engine stand this week to break it in. Goes into the car this weekend. I'll give a report as to what happens. ps I drive real Hard!!

Tue Aug 01, 2006 1:50 pm

so glenn do you recommend a as41 then?

Tue Aug 01, 2006 3:06 pm

you ought to look for an AS-21 case if you are super worried about strength. those use a stronger alloy than the AS-41 and can be found in fuel injected late model bugs. I think there is one in the classifieds right now.

Tue Aug 01, 2006 3:09 pm

soazvw wrote: so glenn do you recommend a as41 then?

I built my 1904cc on a German Industrial AS-21 case. It's about as strong as you can get... and it's OEM.

Tue Aug 01, 2006 4:17 pm

Is _anyone_ making a _correctly_ machined aluminum case? I've never heard of anyone putting together a motor based upon a aluminum case without major corrective machine work. There's a fellow on the type2 list whose aluminum case turned into a supreme money pit.

I think I'd look into converting a wasserboxer case before I went for an aftermarket aluminum case. There's still a lot of machining involved, but at least you start with a VW factory case that is predictable.

George

Tue Aug 01, 2006 4:27 pm

empi cases are the best, believe it or not, and they are cheaper.

Tue Aug 01, 2006 6:18 pm

Glenn wrote: Most if not all of the aluminum cases are sand cast and are brittle.
http://www.webelements.com/webelements/elements/text/Al/xtal.html
http://www.webelements.com/webelements/elements/text/Mg/xtal.html
Observe that magnesium has a hexagonal close packed (HCP) crystalline structure, while aluminum had a cubic close packed or face centered cubic (FCC) crystalline structure. The HCP structure has only one close packed plane while the FCC structure has 4 close packed planes. The likelyhood of four planes having one aligned in the direction of applied stress is much greater than only one plane, therefore dislocation motion inside the FCC crystal grains is much more likely to occur resulting in plastic deformation, while in HCP applied stress will more likely result in high stress concentration at grain boundaries leading to microcrack growth and finally macroscopic crack development and propagation.

GeorgeL wrote: Is _anyone_ making a _correctly_ machined aluminum case? I've never heard of anyone putting together a motor based upon a aluminum case without major corrective machine work.

http://www.grupohubner.com.br/autolinea/04_produtos.html

I've got an Auto Linea case. It arrived ready for a stock 1600. The only work I had to do was bore it for 90.5mm cylinders, clearance it for a 78mm crank, and weld, drill, tap, and plug for full flow. These would all have to be done to a stock magnesium case anyway, and the welding was much easier on aluminum.

I will say that the oill pump I have was 0.050" out of alignment with the oil galleys in case, but that was remedied by a 0.050" thick piece of aluminum and a hole saw to shim it out.

Being that Auto Linea casts nonferrous parts for Catapillar, Ford, VW, Mercedes-Benz, Scania, and Volvo, I feel that I can trust their abilities to do it right.