[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]
I ran a tuned 1600 pancake in my fastback for a year, and then changed to a tuned 1835 'Beetle' style engine. On both engines I had small cracks in the cylinder heads. These were related to running compression ratios of around 9.5:1 and not the bigger bore. I eventually changed to the upright engine due to the difficulty of working on and getting performance parts for the pancake engine. Gene Berg did not advise Pistons over 90.5 due to the barrel warping, I believe he was over cautious. Be aware that changing to the 92mm pistons will automatically raise the compression ratio. I'm not sure exactly by how much as I can't find my Dellorto book, but it may go from 7.7 to 8.4 ish,(I,m sure someone will correct this), and this could cause more problems than anything else by rasing the cylinder head temp and causing pre-ignition. As for ways of reducing heat build I would recommend fitting a full flow oil system, which is generally good for the engine, but also increases the amount of oil in the system. Also the use of a deep sump, available from Berg or Bugpack will greatly increase the amount of oil in the system and help in keeping the engine cool. Adding an extra oil cooler is an option but on a well built engine with a deep sump should not be needed and can cause more trouble than good if it is not installed correctly. A further benefit of a deep sump is to ruduce oil starvation on heavy acceleration and heavy cornering. As a final comment, If you require more go than the stock engine, then the 1835 route is will provide a much simpler and driveable car than tuning the 1600