More Dilivar Q/A
 

Sorry to bring up this topic yet again, but I'm still confused.

Rebuilding 87 Carrera 3.2 for street use after 150k mi. Dilivar studs not broken and black coatings intact. Mine are NOT fully threaded.

Various posts, including by Wayne himself, seem to imply coating applied after 1984 greatly reduced incidence of failure. There's been a few posts from 87-89 owners with failures, but majority seem to be by owners of earlier cars. I've seen this problem attributed to corrosion and/or faulty heat treatment. Don't have one but could I have the other?

Have dreaded Alusil P&Cs, but bores pristine with original spiral hone marks still visible. Rather not mess with these if I don't have to.

You have the original Dilavars which should not be re-installed due to corrosion issues.

993TT Dilavars are the best head studs IMHO, but certainly not cheap.

Thanks Steve. Yours qualifies as authoritative opinion. I'll go get my pipe wrench and list of curse words. I can leave the steel intakes alone-right?

I have started to see Dilivar head stud failures on Carreras now too, not just the SCs. I would replace.

So much for that. Pipe wrench bites very nicely into threaded end. Thanks guys for talking me into this. Don't know what I was worried about.