Oil pressure fluctuating at idle

[wazzabie]

The oil pressure on a chevy 350 is fluctuating at idle. It does not matter if the engine is warm or cold. I always have oil pressure. Engine sounds like a sewing machine. Maybe a bad lifter. Thoughts?

[geezer#99]

Bad lifters and several flat cam lobes!
Pop off the valve covers and check movement of the rockers.

[wazzabie]

Originally Posted by geezer#99

Bad lifters and several flat cam lobes!
Pop off the valve covers and check movement of the rockers.

How would I check movement of the rockers with the valve cover off? Should I have the engine running? What should I be looking for?

[Dead Parrot]

Easiest is valve cover off and engine running. It WILL be messy! Do one side at a time. Check for all rocker tips moving about the same amount. If one isn't moving much, that is your suspect.

Might cut open your oil filter and check for metal bits. Not definitive as a bad lifter doesn't normally make many metal bits and a worn cam lobe might have failed before your last change. If you find a bunch of metal, something is failing.

What is your idle speed? A stock SBC will often idle smoothly well below the recommended idle speed. Too slow can show some oil pressure variations.

[wazzabie]

Originally Posted by Dead Parrot

Easiest is valve cover off and engine running. It WILL be messy! Do one side at a time. Check for all rocker tips moving about the same amount. If one isn't moving much, that is your suspect.

Might cut open your oil filter and check for metal bits. Not definitive as a bad lifter doesn't normally make many metal bits and a worn cam lobe might have failed before your last change. If you find a bunch of metal, something is failing.

What is your idle speed? A stock SBC will often idle smoothly well below the recommended idle speed. Too slow can show some oil pressure variations.

There is fast idle and curb idle. Curb idle is at 700 rpm. Fasts idle is at 950rpm until the engine warms up and I kick down the idle cam.

The fluctuating engine oil pressure happens consistently. At either idle and when the vehicle is running at speed. Also the engine has sat for about 10 years with little use.

[cadillac_al]

Is this an electric gauge?

[wazzabie]

Originally Posted by cadillac_al

Is this an electric gauge?

Yes

[kwmech]

What oil filter is on the truck? and sometimes fluctuation can mean the oil level is low

[wazzabie]

Originally Posted by kwmech

What oil filter is on the truck? and sometimes fluctuation can mean the oil level is low

Wix 51061

[wazzabie]

I pulled the oil filter and examined the internals. I don't see any metal debris. There is carbon like chunks in the pleats. It has about 30 miles of driving time with the engine oil. I also used an additive to the engine oil.

[kwmech]

Carbon like chunks doesn't sound good. Any pics of them. Also,.... unbolt the small aluminum adapter that the oil filter screws onto and see if the spring loaded check valve is not messed up or has one of those 'chunks' stuck in it