Engine oil pressure issue?

[imported_ironmike]

Greetings,
I have a 1987 Cruiser, Inc Avanti Vee with twin Crusader 350's, (remanufactured Chevy marine blocks, generation II, carburetor, cast block with cast heads, remote oil filters mounted in the rear of the engine), with approximately 2.5 hours on them. This past weekend I was running both engines at idle and suddenly, after idling for approximately 10 minutes, the oil pressure gauge dropped to 0 . Additionaly, the alarm went sounded. Before the gauge went to 0, I noticed the oil pressure gauge needle fluctuating a couple of times, read approximately 40 to 50 psi. When this happen, I immediately cut the engine off. Also, I did not notice any difference in the way the engine was running when this happened. The engine maintained its current temperature. I restarted the engine and it ran fine registering 40 psi as it had before the alarm sounded. The oil pressure sensor and alarm switch are located at the rear of the engine near the distributor and are both connected to a T connector, which may indicate there was an actual pressure loss. I ran the engine for another 10 minutes without a problem. Can someone tell me the best way to troubleshoot this problem?
Thanks

 

[Uraijit]

Re: Engine oil pressure issue?

My recommendation would be to test both engines' oil pressures separately with a mechanical gauge. Oil pumps rarely work intermittently. In my experience, they either work, or they don't. So if you've got pressure on each engine, it's unlikely that you're really losing oil pressure.

Though, even if you did lose oil pressure, it usually takes a while before you'll notice a change in how the engine is running, especially at idle. The oil doesn't all just disappear as soon as you lose pressure.

Once you've established that you do indeed have pressure, I'd start checking the electrical system, starting with the sender. Test the sender according to the manual, check all connections and wiring. I'd bet that your problem is electrical, since it's unlikely that both engines would have lost oil pressure.

 

[Windykid]

Re: Engine oil pressure issue?

Ahhh anyone check oil level????

 

[imported_ironmike]

Re: Engine oil pressure issue?

Thanks for your response. I left out a small detail which was this occurred on the starboard engine only. An electrical short seems like it could be the culprit. The confusing this is both the oil pressure gauge and the alarm switch sensed low oil pressure. This was a salvage boat. The oil pressure senders were replaced when the motors where replaced and the gauges are new. The engine wiring harness is new. There was some corrosion on the engine harness connector on the plug going to the gauges which I replaced. The may still be an issue with the wires though. I think I know what you are referring to when you say mechanical oil pressure. This must be the one which has plastic tubing that connects to the gauge. Would I be able to purchase this from an auto parts store? By the way, the engine has the oil filled to the proper level
Thanks