hello My golf mk2 1.6 ez is having problems when shutting off engine when warm. The problem is that I broke the nipple on the non return valve that connects the distributor vacuum line. I have tried to block it off with some glue and tape, but that doesnt seem to work. It sounds like the engine is still rotating and then a steam sound comes, when i turn the engine off. I have just changed from pierburg to Weber 32/34 together with a 4-2-1 manifold and full stainless steel exhaust. So my best guess is to buy a new non return valve or do you guys have some good ideas?