Hey everyone,

I now have a little over 6K km (~4K mi) on my rebuilt B230FT. I'm planning to switch it to Mobil 1 in about 1000 km or so. At that point the engine will have just over 7K km (~4500 mi) on it. The engine is working great and has been running on Penzoil 10W30. It was changed first when the engine had ~300 km, then at around 1200 km, next at ~4200 km. I have previously recieved opinions from some members of the board on when to switch to synthetic. I combined all the opinions and decided that it would be good to switch when the engine had around 7000 km (~4500 mi) under it's belt. I was just wondering if you guys still think this is an acceptable time? The only real issue with the engine has been a moderate slapping/knocking sound at idle RPMs (95% of the time only when it's below operating temp) that has persisted and hasn't seemed to get better or worse. My Vo mechanic is not sure what the sound is, but the oil pressure is fine, and the valves are within spec. His only guess is that it's the bushings where the pins go through the top of the connecting rods, but he said that they seem just fine when he assembled it. He's denying piston slap because of all the new parts and proper bore fitting. Anyway, I'm interested to see whether the Mobil 1 will quiet the noise or not. I'd kind of like to get Amsoil, but I can find a distributor that is near to me. Oh well. Do you guys think the engine should have a flush before the switch? I wasn't going to because the engine was cleaned internally during the rebuild. The only things that haven't been extensively internally cleaned are the head and the turbo. The turbo now has ~267K km on it and is running strong (knock on wood) putting out somewhere around 9-10 pounds of boost. The engine hasn't seemed to be using any oil, although, I know a *little* is comming out through the turbo seals I think, but it's not showing up on the dipstick after ~2K km, so it can't be much. Sorry about dragging on the post, but I just want what's best for my new engine :) Oh, I'm planning to run the first Mobil 1 change for ~5K km, the second for ~7K km and then I'm going to use the service light (8K km) thereafter. Sound good? Thanks in advance!
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Chris. Halifax N.S. '91 745Ti, 261K km.