PostVW

I am maybe going to buy a nice –83 911 SC but I heard that a common problem on the 3,0 engines is broken studs for cylinder head. Are there any methods to verify that/if the studs are OK? How often will this problem occur? Can it be repaired by anyone? Expensive? Should the car be treated (in future) in some special way so this problem will not occur?

Peter Zimmermann

The '83 has the least chance of having the problem. If it does occur but the car needs nothing else the cost is about $2500. The work should be performed by an experienced journeyman or master Porsche technician. Using updated studs the problem will most likely never re-occur. To verify that the studs are OK remove all four valve covers and check that all 24 cylinder head nuts are there and tight.
Pete

PostVW

Pete,
Do you have any idea of how many (x%) of the cars are affected? Is a high milage car a bigger risk than a low milage?

Kenneth

Peter Zimmermann

I couldn't guess at the amount of SCs that have been/will be affected, but it was a very small percentage of my very large clientele. Please remember, my shop was in Santa Monica, and SoCal has a mild year-round climate, so the problem might certainly be far more severe elsewhere. Regarding mileage, we saw the problem much more often on low mileage cars and garage queens - four out of five cars that we did the repair on were low mileage. Of course, we now have to take another look at what "low mileage" is. For example, a 1980 SC is TWENTY-SIX years old. Let's say we find a really nice one with only about 100K miles on it. That car, today, must be considered "low mileage." 100K miles divided by 26 gives you a yearly average of under 4K miles. In 1990, when we found a couple broken head studs on a 38K mile '80 SC, we considered it to be a "low mileage" car. SCs are beginning to edge into that territory where a "repair" should actually be considered a "restoration." As a result we're going to have a bunch of SCs fall into a state of disrepair that they might not recover from. We're already reading about how badly many of the cars shift, but a professional rebuild of the transmission can fix that. Unfortunately, that rebuild, including clutch replacement, will total a significant percentage of the car's value, sometimes close to 50%. When you look at a high-mileage car you will often encounter other problems (cracked dash, worn seats, badly finished wheels, brake & trans issues, Targa and Cab top problems, coupe sunroof problems, etc.) that will be far more costly to repair than head studs on a low-mileage car. Yes, low mileage SCs in excellent condition are still bringing serious money, and deservedly so, so a PPI is important. But, if you find the perfect 40K mile SC, and you buy it, and you start driving it regularly, there is no guarantee that a head stud that's been quietly corroding over the last 15 years won't break. On the other hand, nicely maintained, garaged, high mileage SCs are getting very hard to find, it's not quite the situation where "you've got to be in the right place," to hear about one, but it's getting there.
Pete

PostVW

The car I am interested in is a good looking 83 SC cab with only 38000 miles. All original, including paint. But it´s not cheap so thats why those studs can be a potential problem.