Head Stud Tink Test
 

Hello all, I currently have my engine and transmission out of my ‘83 911SC. Mostly because of the transmission, but that is a different story.

The work I am performing on the engine is installing updated cam chain tensioners, chains, sprockets, sprocket supports, and attend to oil leaks. I find it amazing that the updated tensioners were never installed in its 40 years since birth. The engine appears to have never been opened other than valve covers for valve adjustment. The triangle of death is dry, and I do plan on giving it some attention.

I didn’t perform a compression or leak down test prior to my removal. Hindsight is obvious at this point. The engine looks pretty clean inside. The interior has a light brown oil color on the walls that comes off with solvent, at least my chain cases do. Maybe driving and good detergent oil will clean it up. Anyone use engine cleaner for n a 911?

So on to my general concern with head studs. Prior to all of this I did a valve lash adjustment, and none were very far off. No head studs lying about.

I thought that since the head studs are under a lot of tension, maybe I could tap on each and discern a broken head stud from a good head stud with a “Tink Test”. Holding a steel dowel to the stud just above where it threads into the case and striking the dowel with a hammer to hear the sound in makes. Similar to checking for loose spokes on a bicycle or motorcycle wheel.

So, for now, i’m going to call the engine sound. And i’ll perform the leak-down after I get the cam drive back together.

Thoughts anyone?

They are either broken or not. If they are steel and look good (not corroded) they can be reused. If they are dilavar (black color) they need to be replaced- even if they look sound. Just retorquing a dilavar stud can cause it to snap. On our engine rebuilds, we always replace head studs because it would cost more to fix later than buy new from the start.

If you're on stock head studs and have the engine out and torn down to chain boxes, I think you'd be crazy not to replace the dilavars. Ticking time bomb -- and you've already done 85 percent of the labor to get to where you need to be to replace them.

If you ignore them, six months from now they're going to start snapping and then you'll want to stab yourself with a broken head stud for not doing the job now. Murphy's law.

I agree now, it’s time for an entire overhaul. I don’t believe this engine has

(OPPS)

NOT been touched.

Have you confirmed that the lower head studs are still Dilavar? With the motor on engine stand, it would take only few mins. to verify if they are steel or Dilavar by using a magnet for the test. How total many miles on the odometer?

Tony

Hi Tony, the bottom ones are non-magnetic “Dilivar” as you suspected. The Supertech brand is in my future…��

Certainly nothing wrong with the Supertecs but just replacing the bottom ones with stock steel studs will work out just fine too.

All or nothing…;)