I don't mean where water gets around them and 'afixes' them in place around their sleeves, I mean the 'blowby' (for want of a better description) builds up securely affixing them in place.
Are the seals not up to it ? , the compression is not really much different in a DI vs IDI unit, then again the fuel pressure can be ten times higher...
I do wonder if they were screwed in this would not happen but then again they would probably snap off if subjected to extreme removal (for replacement) force such as a whizzy gun.
Looking around most manufacturers use clamps rather than threads for Direct Injection units anyway so its not a PSA concern, the only indirect injection unit I am aware of that uses clamps is the ancient 2.25 LR diesel all iron (OHV!, although better than sidevalve I suppose) unit.
I wonder if I have overlooked the obvious reason for a clamp, I thought about costs but it seems all manufacturers use clamps on DI units.
