Dilivar Studs on 2.7

[djtalon]

Are dilivar studs on 2.7's what is desired or not; read alot of posts and can figure if they are good or bad

[Jase007]

Dave:

Are you asking if dilivar studs are on 2.7L motors or ...

are you asking if it is a good idea to put them on a 2.7L motor ...?

[Trak Ratt]

Dave:

Are you asking if dilivar studs are on 2.7L motors or ...

are you asking if it is a good idea to put them on a 2.7L motor ...?
Suspect his paper work on the 2.8 rebuild says Dilivar. Dilivar used to be the standard, then they started breaking too. There’s something new almost every year and the interwebs correctly identify the trends 12 out of 8 times :p
Nuth’n last forever and now the 3.0s and 3.2s are snapping studs.

[Cliff Claven]

Dilivar delivers. 25 plus years is good enuf for me.

[Spike]

I think you'll find opinions all over the place for alloy, steel, dilivar, etc. I believe one current thought is the dilivar expands and contracts at the same rate as the Mahle cylinders and head, so stress is kept in check. Others feel high end race quality studs are the way to go. I've never seen any scientific results compiling one vs. the other.

I have Supertec studs currently and they work fine. I had dilivar prior to rebuild and they worked fine.

[Lupin..the..3rd]

Dilivar delivers. 25 plus years is good enuf for me.
Exactly. The originals lasted 25 years, replace same-same and you know how long they'll last. Replace with something else and who knows. Not saying steel/arp/raceware/etc are bad, just saying there's not enough data points to make a comparison.

[markwemple]

I thought that the current thinking is to aviod them like the plague; to go with standard steel or upgrade to raceware, etc. Funny thing is that the early cars, pre-2.7, run steel and never had problems, it wasn't until thermal reactors, 5 blade fans and turbos that Porsche came up with dilivar to deal with the issue. Remember that no stud will expand and contract at exactly the same rate and that the alloy and thickness affects waht is happening.

Honestly, aren't they all compromises?

What do they use in small aircraft engines. They don't leak and I've never seen a broken stud in one.

[Noah]

Steel studs are the way to go. One of the problems with dilivar has been poor quality control -- many batches have been defective and studs break with the engine sitting on the stand.

[matt de maria]

Dilivars were made to match the axial expansion of the barrels. Using steel almost doubles the stress in the threads in the block. Thats why the 2.7 pulled studs---high temps and magnesium.
In short you have to make a careful choice on what type of stud to use based on what you have, how the engine is to be built and what long term goals you want.

[Trak Ratt]

Matt, aren't there new coatings available that delay the corrosion on the dilivar studs too?

[matt de maria]

They were epoxy coated but that didn't work. A lot of them that failed in service seemed to break where the top fin of the barrel chafed and wore through the coating and into the surface of the stud causing a stress riser and then fracture.