In the video below we take a look at the repair of one of the ‘difficult to detect issues’ that can be present in an air-cooled 911 engine. 

It’s an issue that has been around since the beginning of time, and it’s hard to detect, but essential to fix. 

On air-cooled Porsche there are six cylinders, each held on by nuts threaded onto a long stud, so, with the engine expanding and contracting every time it’s used, it can cause stress on the studs. These studs can then snap, and when they do, although the car runs it can allow the cylinder gases (the compressed fuel/air) to escape, and that can lead to damage to the actual cylinders and head. 

There are tell-tale signs sometimes, a chuffing sound upon acceleration, (as the compression escapes) accompanied with a clapping sound as the cylinder moves against the barrel. It may also display some oil leakage from the affected cylinder. 

It’s definitely a fix now, not later scenario. 

The fix requires the engine out and the cylinders removed, quite a comprehensive strip down. Whilst there, it may be the right time for a refresh or top end build. The broken studs usually fail as they enter the crankcase and can be a devil to remove. 

We have our own engine repair shop here at Williams Crawford, and we have been building engines for all Porsche, modern and classic, for years – so, we know how to resolve the issue and what to do to extend the life of the engine, which nowadays includes better stud material.

This video gives a close up of the problem.