Pelican Parts Forums - Neat site for 917's

Very good site. Most everything I saw was in English, although its obviously a translation (but a decent one at that). What I found interesing was the reason Porsche abandoned the Weltmeister in 1972 - it was VWs fault!

Quote:

Porsche’s decision to retire of the competitions was the logical result of the panorama offered to the German signature by the new regulation that would govern the World Championship of Makes in 1972.

650 kilos of minimum weight, and only three litres of piston displacement, thus said the new rule.

This rule gave Porsche only one alternative: if it wanted to stay competitive, they were to design and build a much more powerful motor that the one they had at the moment for the 908/03.To improve the power/weight ratio. That was the problem.

And it was a problem because the technical parameter that bonded Porsche with Volkswagen’s financing, was the use of air cooling exclusively, and in this case its construction did not allow the use cylinder heads with four valves each (matter of space and heat transfer). Not being able to use this layout in the heads, it was not possible to reach high specific power (same situation happened in the 12 cylinder, 5-litre engine).