Quote:
Originally Posted by PaulD
the original 1600 motor in my Bay is based on an VW AS21 case by the looks of it. I'm thinking about building a new motor from scratch on the bench over this winter, and I've noticed that most places sell AS41 cases.
What is the difference(s) between an AS21 and an AS41 case?
Are AS41 cases stronger internally?
Would an AS41 case be suitable for the basis of a 'warm' but reliable motor?
maybe i should buy a book!!
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The difference is mainly down to the material.
People building hot engines always used to swear by the AS21 cases. For 2 reasons, they are stronger and the early AS41 case weren't that great.
http://www.shoptalkforums.com/viewto...e13f66fd812815
2 things have changed since then, AS41 cases got better, plus you'll be lucky to buy a new AS21 case for 2 gold pigs.
Most people build street engines round AS41 cases these days. And provided you build it using the right components, full flo it, use nice original tinware and don't go besurk on cam selection etc... you should have a reliable engine. But yes you should consider getting a book and go to your local club and speak to people who've done it.