It would be a simple matter to wire a buzzer or a warning light through an oil pressure light switch that would indicate an "ignition on- - - -engine off" condition. Once oil pressure builds up within a second or so of engine start, the warning system would shut off automatically, and stay off as long as there's oil pressure present. Most of those switches have a 7 PSI turn off pressure, so it would also serve as a "loss of oil pressure" warning.

www.ebay.com/itm/388768493582?

www.ebay.com/itm/255002901490?

Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!