Deve,

All you need is a Normally Open Timed Closed realy, your 6psi Oil Switch and Buzzer to make this work.

Power the NOTC relay coil with Keyed 12vdc and Ground.

Wire the relay N.O. contacts and oil switch contacts in series to the buzzer using the Keyed 12vdc and Ground the buzzer and your done. The NOTC relay will keep the buzzer circuit open long enough for the engine to come up to pressure. When the key is turned off the cycle starts all over again

Here's a 10 second relay I found on Amazon

http://www.amazon.com/AH3-3-0-10Sec...-16&keywords=time+delay+relay+12v+dc

Hope this helps,

Mike B smile

Mike Boteler

1956 Chevy 3100 Resto Rod
1952 Willys M38 Army Jeep
1983 Jeep CJ7 Laredo
1984 Jeep CJ7
+++++
Silver Spring, MD