Which six ??? They are ****house anyway... I changed turbos on 3 astra turbo 1 hsv. They all have plastic covers and all leak and need new gasckets at 80k.
Yeah I thew my plastic one out....they're ****. If you are going all this trouble maybe shave few grams..lol might as well invest on a fly wheel takes 5kg or more.
You'r meaning the top cover yeah?. I've never seen a plastic one, all my cars and spare engines are alloy.
Besides you want to conduct heat away from the engine, not hold it in.