Quote:
Originally Posted by AlfonsoR
Yeah, I'm in the expansion rate camp as well. But I've been wondering, what exactly lead Porsche to develop Dilivar? Sometimes the engineers over-think things and the field guys just make it work. So what if you use a high-strength alloy and the cylinders get distorted by a few microns when the engine is hot? There are plenty of other variables that affect engine longevity.
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There is a LOT more to this that meets the eye.
Nothing was 'over-thought' at the factory on this since maintaining proper clamping pressure affects head sealing and cylinder concentricity at all temperatures. Its not a strength issue since after all, the steel ones are plenty strong.
The principle is maintaining consistent head torque under a very wide range of temperatures and IMHO, Dilavar excels at this, based on my personal experience. Naturally, this isn't as critical with low-compression, smaller bore, modest output engines, however large bore, turbocharged or high-compression motors have different requirements.