Engine/Drivetrain Vibration Issues

[apardal]

jondee86, thank you very much for your thorough replies.

To explain better the sound, I should say that it is a sound similar to that made by the clutch release bearing when it goes faulty including vibration easily felt on the gear lever. I think I haven't written about this earlier but that was my main thought because I didn't put a lot of grease in it. One morning, a few weeks ago, I disassembled the gearbox and greased thoroughly the bearing and reassembled it again. The problem was still there (although the bearing was the same... it is 2 years old).

I've exchanged some mails with the guy that sold me the solid pinion spacer (Spence Weir) and he told me both the clunk and the vibration could come from incorrect LSD bearing preload. I don't think so, because I remember the procedure and I don't think I got it wrong. And that would also cause some whining under acceleration, I think.

The compression ratio was indeed increased, but not that much, because I was already running a decked head 0.6mm, decked block 0.1mm and 0.5mm head gasket on OEM pistons. By my calculations the CR was around 11.5:1. Now, with the wiseco pistons and a 0.8mm head gasket I'm around 12:1.

Tomorrow morning I'm going to align the wheels and steering since it wasn't aligned since I installed the Greddy Coilovers. That can cause a lot of strange vibrations, for sure... but I don't think it is the source of the problem... But I need to do that anyway.

I've talked to the crank balancing shop and they said (of course) that they have no prior balancing errors. That the machine is pretty accurate.

Tomorrow I'll have some news. Next week I'll disassemble the oil pan and measure (with plastigauge) crank/bearing oil clearances and I might measure rod/bearing oil clearances also while I'm at it.

About the fuel cut on overrun, I honestly don't know what that is, but I'm running stock ECU with an Apexi SAFC1 piggy back.

Again, thank you very much for your interest and answering all these questions.

Best regards

André Pardal