head stud opinion

alniki · 03:01 AM

Talked to my wrench about replacing the 3.2 original Dilavar head studs. He thought most head studs cracking was caused by human errors. He's been keeping the original head studs at numerous engine rebuilds for many years without any failure. But his experiences probably are based on more 964 M64 engines than Carrera 3.2.

When I tored down my broken engine, I found a cracked exhaust Dilavar head stud. The engine might have had a rebuild before as the case-thru-bolts have the aftermarket blue O-rings instead of the original dark-red ones, I'm not sure.

The concensus here seems to be for replacing the studs anyway. But then I have to talk my wrench into removing the exhasut Dilavar studs, which is not an easy job and probably would damage the threads if not properly done. Then I have to worry about the new steel or 993 Dilavar studs not being properly installed.

Should I insist on the replacement or take his advice and save all the money and trouble/worry?

88-diamondblue · 07-10-2009, 08:28 PM

CHANGE THEM! and don't take no for an answer. I had two broken on an 80,000 mile well cared for and stored winters Carrera. The dilavar studs will break. Replace them with Porsche steel studs unless this is a turbo engine. Removing them is not too difficult, I needed heat on only two studs when removing them. Installing new studs is easy to do, just need to be measured for height. Porsche steel studs are around $12 each 911 101 172 00

The blue silicone o-rings are the original ones. Replacements are the reddish color viton o-rings.

Jeff Alton · 07-10-2009, 08:46 PM

replace the bottom row with inexpensive factory steel studs.

Removing the existing ones should not cause your experienced wrench any trouble....

Cheers

alniki · 07-11-2009, 03:22 AM

Thanks! I'll replace them. Talking the wrench into doing something different is a tricky thing. You just don't want to hurt his pride and feeling because it's him who will be rebuilding your engine and you definitely wish he likes, not hates, you.

Since it's the swap engine I purchased after the disaster that is to be rebuilt, can I reuse the 12 upper-row steel studs of my original broken engine for the rebuild?

Also, the O-rings looked light blue while the aftermarket ones are deep blue so they may be different. But those from my 'genuine' Porsche rebuild gasket kit are dark red.

Flat6pac · 07-11-2009, 07:24 AM

He might not like it but if he cant warrant the work with the old ones because as soon as he torques them to Carrera spec you can be sure there will be broken studs on the floor before he gets it closed up.
Bruce

kenikh · 07-11-2009, 07:55 AM

A 3.2 case should not have removal issues. Mag cases may sometimes, but no aluminum cases. FWIW, I just bought Supertec studs yesterday. Best engineered stud out there, IMHO. 993 are my 2nd choice.

darkbeer · 07-11-2009, 08:56 PM

everything above matches my experience....Dilavar is French for Disaster & in Croation, Dilavar means disappointment....
never reuse ANY stud....they are very reasonably priced so buy new factory steal ones. A simple propane torch is all that is needed to melt the locktite so you can "double nut" the old studs (we're talking only about the exhaust studs) out...or, if broken (usually about half way down) then use a really good sharp strong visegrip....
Wayne's book gives you the measurement for the stud heights & it's so easy to get them all in & right....
best of luck !!!!

alniki · 07-12-2009, 01:30 AM

Wow, kind advice from Croatia for my Deutsch roadrunner in Taiwan? Never been to The Adriatic Sea but the French Mediterranean Sea and sky looked good enough to my eyes. Is it legal to share a couple pictures here?

The southern end of Taiwan, Philippines is on the other side of Luzon Strait.

The southeastern part of Taiwan, USA and Mexico are on the other side of The Pacific Ocean.

Steve@Rennsport · 07-12-2009, 11:43 AM

Quote:

Originally Posted by alniki

Interesting buildings,....is that some kind of radar installation?

alniki · 06:29 PM

Ah, Steve, Portland is just one huge pond away from here.

Interesting to a pilot's eyes? A military setting I guess but likely not of high confidential order or I'd not have been able to shoot it just from the roadside. Anyway, this is the 'Pacific' side of Taiwan, not the western Strait side facing the hostile/threatening China.

Jeff Alton · 07-13-2009, 07:34 PM

Yes, for your application, re use the top set of studs and replace the bottom row with the same, factory steel studs. If you are building a high performance motor, then consider one of the aftermarket studs (supertec or ARP) or maybe 993tt dilivars.

Cheers

alniki · 08:37 PM

Jeff, thanks a lot!

You know, I've been secretely thinking for quite a while since well before my engine disaster -- Maybe I should just get Jeff's 3.4 if he'll ever be selling it....

BTW, maybe we can use studs from Supertec, ARP or Raceware on the bottom row only for a high performance engine. Ever heard of top row stud failure in a later aluminum case? If not, that's probably feasible and you save about 300 bucks for the studs. Any one likes to share a high performance head stud set?

Steve@Rennsport · 07-14-2009, 12:07 AM

Quote:

Originally Posted by alniki

Ah, Steve, Portland is just one huge pond away from here.

It sure is,.......

Quote:

Interesting to a pilot's eyes? A military setting I guess but likely not of high confidential order or I'd not have been able to shoot it just from the roadside. Anyway, this is the 'Pacific' side of Taiwan, not the western Strait side facing the hostile/threatening China.

Good call, indeed I am.

I found it on Google Earth and it looked like an over-the-horizon, early warning radar installation.

alniki · 07-14-2009, 01:50 AM

Quote:

Originally Posted by Steve@Rennsport

I found it on Google Earth and it looked like an over-the-horizon, early warning radar installation.

Bet you're right because there is an air base in that region and 20 years ago I served in one that flew F-104 Starfighter, later changed to the French Mirage.

jacksd3 · 07-14-2009, 06:13 AM

Hi Alniki, I am doing a rebuild now and using ARP for both head studs and rod bolts. I was impressed by the quality of the products and their packaging. I'm using the green o-rings and Dow 55 o-ring lube that I got from Henry Schmidt for the case thru bolts. Some really smart engine builders on this board recommend the 993 fully threaded head studs for your engine. I went with ARP because of price.

Best of luck!