The engine for the 1977 Porsche 930 is completely disassembled and ready to be machined. All in all, the internals look like they’re in pretty good shape. We had been wondering if the engine had ever been apart before, but finding a piece of the previous timing chain inside of the case cleared any previous doubts.
In the late seventies, Porsche increased the horsepower of their engines causing them to retain more heat than they had previously. At that time, Porsche engine blocks were made of Magnesium, and the cylinders were made out of Aluminum. Porsche attached the cylinders to the block with head studs made out of an alloy called Dilivar – specially designed to heat and cool at the same rate as Aluminum and Magnesium… Unfortunately, Dilivar did not work as well as our friends at Porsche would have hoped, and because of the different rates heating of Magnesium and Aluminum, when the cylinders and engine block heated up and expanded, the head studs would pull out of their threads in the engine block, and would not return when the engine cooled. The engines would literally tear themselves apart after time.
Here we have a few images of what can happen when the heads begin to pull off of a 1977 Porsche 930 motor.
In this particular engine, the head studs had pulled out so far that the engine’s timing chain was pulled off of its guides and was riding on the bolts that held its guides and rubbing against the timing chain cover.
The expanding / contracting problem can become so bad that head studs will actually break… here are a few below.
This very original 1977 Porsche 930 came in for some engine work. The car has suffered from some pulled head studs and also has a few rather unhealthy vacuum leaks. We’ve pulled the motor out for this job and will be working through the issues in the next few weeks.
This 1977 Porsche engine looks as if she might need a little bit of love. After running some quick diagnostic checks on the motor, we’ve found that there are some massive vacuum leaks, and the motor is running on just 2 of her 6 cylinders. All 6 spark plugs are pretty badly fouled and we’ve found quite a few nasty oil leaks.