Case ID questions

Slim71 · Post by **Slim71** » Mon Aug 05, 2002 1:19 pm

I'm rebuilding my 71 Super, and I want to beef the motor up some to increase the hp (90.5 cylinders, mild cam, reworked heads, etc). The problem is I'm having some trouble ID'ing the case.

It's an AE case, stamped AS41. But it also has the washboard ribbing above the oil dipstick, and has a 3 rivet cam.

What I'm trying to determine is is this case going to be able to handle a rebuild, or should I look for a "new" case (AS21 or Brazil AS41)?

I don't know if the motor has been rebuild before, but I have a feeling it's been opened up (maybe that's where the cam came from).

I've already done a search through the Forums and Gene Berg's site. Funny thing is, both the VW shops in my town swear that the AS41 is a stronger case than the AS21. Go figure...

[This message has been edited by Slim71 (edited 08-05-2002).]

71Vdubber · Post by **71Vdubber** » Mon Aug 05, 2002 2:44 pm

I've recently changed cases from an AS21 to an AS41, so I've been doing some reading, and it seems that the AS41 alloy has been upgraded to by adding more aluminium. So both views might be correct, in that the AS21 was a better alloy, but not any more.

As for the case:

Open the case and check the bearings to see if they are STD or oversize. It's marked on all of them. 65mm is standard size, so if the case measures 65.5mm then it's already 1st oversize.

Then check the thrust to make sure that it measures over 21mm.

Hold a straight edge across the six main mating surfaces, next to the main bearings and check for case twist.

If the case passes all of those checks, then it should be ok to be bored and have the thrust cut.

[This message has been edited by 71Vdubber (edited 08-05-2002).]

Post by **Marc** » Mon Aug 05, 2002 3:14 pm

I'd still take AS21 over an early AS41 case, but yours (ribbed) is a potential winner.
Be especially concerned about the condition of the webs for the main bearings - it's unlikely that you'll still see the original milling marks, but hopefully there will be little evidence of severe pounding; if there's a "edge" around the perimeter of the pads that you can feel with a fingernail, it's a loser. If it looks OK so far, clean the mating surfaces and put the halves together, just 2 nuts on the center main studs will do, just use them to draw the halves together - look through one end of the crank bore and shine a flashlight in from the other, see if any slivers of light show up at the parting line between the halves (particularly at the center main).
If it passes this "daylight test" it's worth checking out further....

Slim71 · Post by **Slim71** » Mon Aug 05, 2002 3:25 pm

Thanks guys! That helps a lot.

After giving the halves a THOROUGH scrubbing (BTW, Simple Green will cut through the toughest baked on crud!), I noticed that the case has been drilled and "case saver" inserts have been installed. Whether they're factory or not who knows.

I'm pretty sure this is a later AS41 case that had been opened and an early 3 rivet cam was installed. I'll check the case out and post my findings.

Slim71 · Post by **Slim71** » Mon Aug 05, 2002 5:50 pm

Well, everything seems to check out OK. The bearings are at 65mm, the mains passed the straightedge test, I couldn't detect any edge on the pads, and the case passed the daylight test (although I had to use all 6 bolts to get it closed down tight).

Next step is to take it to the shop and have a thorough exam done on it.