930 Camshaft Question...
 

Hi,
Just beginning my journey of a top end rebuild and just got to the point of removing the chain housing. But that leads me to 2 questions -

a) I realized after opening that housing that the CAM is STILL using the "old" style nuts - 46mm nut requiring the crow-foot Porsche tool to remove, instead of the "19mm screw" type. According to Wayne's book, the change over was around 1980 & mine is a 1987. So... does it mean that someone (PO) might have replaced the CAM? With the fan off, how could I test the camshaft profile now, ro do I need to?

b) That leads me to take a look at the "new" camshaft I bought quite sometime ago (in preparation for this) from ebay. I noticed there's a nick in the bearing (one closest to the rear of engine / chain housing)... DUH! Yes, I know I should have taken a real close look when I first got it. But now - what do I do? Is it still usable? I am thinking I should at least magnaflux it?

Thanks...
:(

it had the cams replaced for sure, but unless there's a number or some other ID stamped on either end, you will have to send them to webcam, or some other grinder, to ID them. a nick on the journal can be dressed with a file to remove any high spot.

Thanks for the comfort John :) From the chain housing end, its the "standards" 930 then the part # (142.00 or 143.00) numbers. Maybe something is stamped at the other end - will find out in a few days when I start to dismantle that.

About the nick - it is really a dent. Looks like someone dropped it into corner of a table or something. There's no high spot that I can see.

So, should I still magnaflux it? I understand you can balance the crankshaft, is there similiar requirement for camshafts?

Thanks again...

My 1982 (now red-beard's car) has the older-style cams in it as well. Looked pretty stock when I tore it apart. Go figure...

-Wayne

the numbers could be what the cam used to be, before it was welded and/or reground, so you'll never know without a cam shop checking it out. cams don't need balancing, as they turn 1/2 the speed of the crank. the dent wouldn't worry me. if a cam had a crack, it would be in two pieces.

Thanks... so I can keep plowing ahead then :)