RDupree, I appreciate you stepping forward, but the problem is
there is no way to test it adequately unless you're willing to run your CTD up to maybe 5000 RPMs and then snap the valve shut. Any takers?
What's the value of the vacuum on the intake side? Well, of course, under normal conditions there is
no vacuum... there's just the pressure your boost gauge reads. But what's the vacuum when your CTD is spinning at 5000 RPM and then instantly the cylinders are sucking against a closed valve? Dunno. Don't wanna know. In various laboratory work I've messed around with 'hard' vacuum many times in my life. Ordinarily you wanna ease on up to a hard vacuum, because scary stuff tends to happen when you just slam it on (can you say "implosion"? Or "catastrophic failure"?)... its like hitting something with a sledge hammer.
Please understand I'm not dissing your valves... I bet they're great for the purpose you designed them for. And I bet you tested them under 'real world' conditions before you started selling them, too. Again, the problem here is we just
can't test them under 'real world' conditions as diesel shutoff valves, unless you can find somebody who is totally off his rocker (and by the way, I'd wanna see a random selection of four or five of your valves tested, so you'd have to find four or five loonies to satisfy me). The engineers who designed these diesel cutoff valves could calculate the forces they would see in action, then designed them to easily withstand those forces, then, I'm sure, tested them thoroughly under those conditions. Its mostly that expertise, design work, and certification that you're paying for when you shell out five hundred bucks for one of these beauties.
When you've seen as many people die in gory, bizarre accidents as I have, you tend to like your safety equipment massively over-engineered, designed by people who are expert in that application, and tested exhaustively.