Chris, after driving my 850 spider for about 10 minutes the oil pressure drops from 40 at 3000 rpm to 20 at 3000 rpm and won't get any higher than 25. Temp is good and engine was rebuilt about 3500 miles ago. Any ideas? Thanks,

Marc

Chris,

When I start my 850 the oil pressure is fine. After running for about ten minutes the pressure drops and light comes on. Oil level is fine and engine has less than 6000 miles. Any ideas?

thanks, Marc

Is it a coincidence that these guys are both named Marc, asking the same question ten days apart? Maybe so . . .

When an 850 engine warms up, some clearances become excessive. Disassembly would be required to determine the fault if this is the cause of the problem.

But, maybe there's no problem at all! Before you do anything else, confirm with a mechanical gauge that you can trust - temporarily hook it up and see what the oil pressure really is.

It might just be that your engine is turning too slowly. It is very common for an 850 motor to have the red light come on during a slow idle when the oil is hot, like just after coming off a blast down the freeway. Matter of fact, I consider this normal!

If the mechanical gauge reveals that your gauge sender is accurate, then you have a problem internal to your engine. Complete disassembly with a critical eye on the complete lubrication system will be needed.