Head stud confusion
 

I've read as many threads on head studs as I can find and am now pretty confused. Can anyone help?

I have a 1977 Carrera 3.0 with several broken studs and am looking at having a top end rebuild done (at about 90,000 miles).

Does Porsche still use dilivar for its studs today? If so, is it the same dilivar that caused so many breakage problems in the past - or have they somehow resolved the issue.

If someone recommends using new dilivar studs for this engine, is this OK? I've seen some comments suggesting dilivar should not be used for aluminum cases - and others saying dilivar is good in some situations...

Does this engine have dilivar studs on the bottom and steel on the top - or are all dilivar?

Is it wise to replace all 24 studs top and bottom - or OK just to do the bottom ones?

Thanks to anyone who can set me straight on this - and I apologize if this has been covered somewhere already that I missed!

JPD1

Porsche doesn't build engines like this anymore. The Dilivar headstuds are still available but I wouldn't use them with an aluminum case. I think most would agree that steel or aftermarket (ARP, etc) are a better choice for an aluminum engine. I don't know for sure but your engine should only have the bottom row dilivar. You should be able to tell by looking at them. If they look different than the top row then they are dilivar. I'd just replace them with stock steel studs.

-Andy

I use the Porsche steel head studs, part # 993.101.172.02. They cheapest steel head studs - about $10-11 each from our hose. Put the part number in the grey parts search box at the top left of this page to find them in Pelican's online catalog.
-Chris

I had nine broken studs and I replaced all 24 with ARP studs - didn't want to do it twice. More money, but it was worth it for me for the peace of mind.

Regards

I have always been an advocate of using the steel studs that Chris mentions. Having said that, I just bought ARP ones for my 3.4 10.5:1 motor. Overkill, maybe, but I do want to try them.......

Cheers