cast crank?

[mark tucker]

my 2028 has a cast crank, but it only has about 50 -60,000 miles on it.

[vugbug68]

for the fairly inexpensive price of about $200 for a counterweighted forged crank, I dunno why anyone would use a cast crank in a vw engine. But thats just me
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[DarthWeber]

^^^I completely agree.^^^

[vwracerdave]

[mark tucker]

[DarthWeber]

[Bruce]

[raygreenwood]

Where are you guys getting this?.....Cast cranks have been used in millions of vehicles....especially many V-8's and straight six's. They just did not have proper casting technology in 1938. Forging was well advanced.
If its designed properly and designed to have the support within the bearing blocks and has the correct mass in correct areas as well as correct overlap across the rod and main journal area there is no reason why cast cranks won't do well...in fact...its been done.Ray

[DarthWeber]

Whenever this "proper casting technology" came about, 40's, 50's, 60's???, then why didn't VW change from forged to cast crankshafts as a cost saving measure? That would have been in VW's heyday and they were all about making a less costly, more profitable (from VW's viewpoint) automobile. Certainly by the 50's, iron casting technology was well known and available to all industrially developed countries. Or maybe the VW engineers just knew something we don't.

[jeff68]

Cast cranks definitely have their place. When I worked with the engineers at US automakers that were responsible for engine component design and manufacture I asked them specifically if, when, why, and about any problems they have with using cast crankshafts. First of all they use cast cranks in engine applications that don't see more than 6000 rpm. The engines I discussed with them were V-6 and V-8 configurations. The high output applications used forged cranks. They used Cast cranks to save money, they are much cheaper to manufacture. They had no problems with the cast cranks in non-performance applications. The OEM's don't manufacture their own cast cranks. One engineer asked me why I was asking about this. I explained I was wondering if it would be a good idea to use a cast crank in an old air cooled VW engine. He said that a forged crank would be better in a an aluminum alloy split case design as the split case doesn't provide the structural rigidity that a solid one piece block does. He said he would use a forged crank in that application.

I'd love to see tests on a forged versus modern cast crank, say an 82mm stroke in a high rpm / power application. Run them identically for say 50 thousand miles and compare case - bearing wear, power output etc. There are many that are running these (I think) but I'd love to see what results would show.

[mark tucker]

scat says 150 hp max on thier cast crank.

[raygreenwood]

[jhoefer]

Exactly. They had already made the huge capital investment into forging. No point in throwing that away to go cast.

[RockCrusher]

To add to what Ray proffered here.....
Henry Ford was the 1st to cast a v-8 block. His engineers and metallurgists told him it was impossible to do and, in fact, there were huge difficulties and all the prototypes cracked while cooling. It was big trouble. I really don't know HOW they solved it but obviously FORD got the process under control for the blocks. VW didn't have any better or newer technology at the time.

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[DarthWeber]

The Gene Berg Book of Technical Articles.

Everything anyone needs to know about cast vs. forged cranks is right in there. Flame on brothers.

[modok]

The main problems i see

-flywheel is held on by dowel pins and a big bolt, so we need the ability to press dowels into it and have strong tough threads

-crank is mainly supported by three main bearings, this does allow a lot more flex than most engines

BTW subaru uses forged cranks, as do most of the import four bangers

[jeff68]

The Berg articles about cast crankshafts have a lot of good information and will give you a lot of questions to ask when you're choosing which crank to buy.

Although the precision casting technology may produce a high quality, strong, durable and dependable crank, how many Chinese manufacturers of VW cranks are using this technology? How about the quality of the finish machine work? Are you getting a precision casting and quality finish machine work with a $250 to $300 crank? I'm not so sure and that's what the problem is, you don't know what you're getting.

[[email protected]]

20 years ago there was a reason to use a cast crank (save a lot of $), because good forged cranks were $500+. Now, I would not even CONSIDER IT, because you can get a great crank for $300.
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[mark tucker]

click reerrrrrrrrrrrrr twang!!! can opened,and then there is the cast steel cranks!!!nodgulaur iron,etc there are so many varaition of material, even the forged versions come in somany different types,4130,4140,4110,5140,5110 and so on, and then the heat treetment or nitriding and what type of nitriding, how much aluminum is in the crank makes a difference on the nitriding & it,s effect. I think it is what you know and what you can afford and what you are sent.I was sent a 4040 crank from cip1 as a 4340 nitrided crank. I can tell the deferance, but I would bet there is a lot of guys who cant. does any body know what the material oe vw crank was made of??

[DarthWeber]

I believe it was 1045??